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Default Compressors - kinda on topic !

Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs
wrote:

* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?

I think Speedair was sold by Grainger. If so they should be able to
tell you which caps yiou need. I just went through this with an old
compressor sold by Grainger. It blew a couple caps and the problem
turned out to be the centrifugal strting switch. I replaced the switch
with and electronic one that sits outside the motor, which makes for
easy change down the road if need be.
Eric
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On 12/3/2018 3:54 PM, wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs
wrote:

Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?

I think Speedair was sold by Grainger. If so they should be able to
tell you which caps yiou need. I just went through this with an old
compressor sold by Grainger. It blew a couple caps and the problem
turned out to be the centrifugal strting switch. I replaced the switch
with and electronic one that sits outside the motor, which makes for
easy change down the road if need be.
Eric


Â* I did some more poking around , found a formula that gave a
believable result . The suggestions they make (a chart) for smaller
motors is in line with my result - looks like I need about 250-270 mfd
with a voltage rating of 250 or higher . I do remember from my days in
electrical type work that a little more is better than a little not
enough ... Compressors are known to need plenty of start torque , so I'm
looking at the top of that range . I'll probably scoot into town
tomorrow before my wife has to go to work and pick one up .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Default Compressors - kinda on topic !

On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs
wrote:

* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?


250 should work. Be sure its at least 350 volts.

This may be of some use:

http://www.capacitorformotor.com/motor_capacitor.html

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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On Mon, 3 Dec 2018 16:08:31 -0600, Terry Coombs
wrote:

On 12/3/2018 3:54 PM, wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs
wrote:

* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?

I think Speedair was sold by Grainger. If so they should be able to
tell you which caps yiou need. I just went through this with an old
compressor sold by Grainger. It blew a couple caps and the problem
turned out to be the centrifugal strting switch. I replaced the switch
with and electronic one that sits outside the motor, which makes for
easy change down the road if need be.
Eric


* I did some more poking around , found a formula that gave a
believable result . The suggestions they make (a chart) for smaller
motors is in line with my result - looks like I need about 250-270 mfd
with a voltage rating of 250 or higher . I do remember from my days in
electrical type work that a little more is better than a little not
enough ... Compressors are known to need plenty of start torque , so I'm
looking at the top of that range . I'll probably scoot into town
tomorrow before my wife has to go to work and pick one up .

The values my compressor uses are quite high, this is because the
motor was made for running a compressor. The high torque demand. If it
still hums after the new cap suspect that start switch.
Eric


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Default Compressors - kinda on topic !

Terry Coombs wrote on 12/3/2018 5:08 PM:
On 12/3/2018 3:54 PM, wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs
wrote:

Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor . Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a
reference
to check ... anybody got a lead on that type of info ?

I think Speedair was sold by Grainger. If so they should be able to
tell you which caps yiou need. I just went through this with an old
compressor sold by Grainger. It blew a couple caps and the problem
turned out to be the centrifugal strting switch. I replaced the switch
with and electronic one that sits outside the motor, which makes for
easy change down the road if need be.
Eric


I did some more poking around , found a formula that gave a
believable result . The suggestions they make (a chart) for smaller
motors is in line with my result - looks like I need about 250-270 mfd
with a voltage rating of 250 or higher . I do remember from my days in
electrical type work that a little more is better than a little not
enough ... Compressors are known to need plenty of start torque , so
I'm looking at the top of that range . I'll probably scoot into town
tomorrow before my wife has to go to work and pick one up .


Does this one look like yours?
https://static.grainger.com/rp/s/is/image/Grainger/19NA97_AS01?$mdmain$

https://static.grainger.com/rp/s/is/image/Grainger/19NA97_AS01?$mdmain$

Or look at all the photos and see which one is yours:

https://www.grainger.com/search?sear...ir+capacit or








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Default Compressors - kinda on topic !

On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs
wrote:

* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?

That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php
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On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?


That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php


The tables at that link appear to only go up to about 1 HP (.746 kW)
and it looks like 80-110 uf is the .373 kW entry in the 220V table,
instead of corresponding to the 6 HP (2.98 kW) Terry mentioned.

A formula at http://homeenergypros.org/profiles/b...ctly-sizing-a-
capacitor
suggests about 164 uF for 3 kW. [2652*amps/volts, ie, 2652*13.6/220].
A rule of thumb in www.elcomp.net/conis.pdf suggests 30-50 uF per kW
(for a 220V 50Hz motor) ie 90 to 150 uF for a 3 kW motor. A formula at
https://www.electricneutron.com/elec...ase-capacitor-
sizing/ calls for a power factor number; I didn't calculate that one.

--
jiw
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Default Compressors - kinda on topic !

On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?



I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

--
Leon Fisk
Grand Rapids MI

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On 12/4/2018 2:03 AM, James Waldby wrote:
On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?

That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php

The tables at that link appear to only go up to about 1 HP (.746 kW)
and it looks like 80-110 uf is the .373 kW entry in the 220V table,
instead of corresponding to the 6 HP (2.98 kW) Terry mentioned.

A formula at http://homeenergypros.org/profiles/b...ctly-sizing-a-
capacitor
suggests about 164 uF for 3 kW. [2652*amps/volts, ie, 2652*13.6/220].
A rule of thumb in www.elcomp.net/conis.pdf suggests 30-50 uF per kW
(for a 220V 50Hz motor) ie 90 to 150 uF for a 3 kW motor. A formula at
https://www.electricneutron.com/elec...ase-capacitor-
sizing/ calls for a power factor number; I didn't calculate that one.

Â* I visited the same site as Clare and I think his number is low too .
I don't recall which website I visited that had this formula : current x
10-6th divided by 2 x pi x frequency x voltage , the result of that
formula was 180 mfd ... I'm going over to my blacksmith neighbor's this
morning , he has a compressor very similar to mine . I'll check his
start cap to be sure but I believe the value needed is going to be a
little higher than that due to the high start torque needed for this
application . This is an Emerson/Doerr motor , but I can't find any info
on this specific motor ... it's at least 20 years old and the Emerson
site just burps and says "not found" when I enter the info from the tag
.. I believe it's going to be somewhere in the 270-330 mfd range . I may
borrow the cap from the neighbor's compressor to see if it works on mine
since they're very similar . If I can't get it going I'm probably going
to order a new motor , they can be had for around 200 bucks and this one
is pretty old . At this point I've got less than that tied up in this
unit including the original (very used) purchase and parts to rebuild
the pump . Nowhere I know of to get a unit of this size and qualityfor
anywhere near that cheap , including a new motor .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !



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On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?


I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

Â* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
.... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Default Compressors - kinda on topic !

On Tue, 4 Dec 2018 07:39:25 -0600
Terry Coombs wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

[...]

I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

Â* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .


Mine is wired for 110 but can be switched to 220v by moving wires in
the motor. The start cap is 649MFD and 110VAC with a plastic case. The
run cap is in a metal case. So that 110 value maybe okay (shrug). A
picture he

https://i.postimg.cc/J7qVkvJD/DSCF0143.jpg

--
Leon Fisk
Grand Rapids MI

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On Tue, 4 Dec 2018 08:03:25 -0000 (UTC), James Waldby
wrote:

On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?


That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php


The tables at that link appear to only go up to about 1 HP (.746 kW)
and it looks like 80-110 uf is the .373 kW entry in the 220V table,
instead of corresponding to the 6 HP (2.98 kW) Terry mentioned.

A formula at http://homeenergypros.org/profiles/b...ctly-sizing-a-
capacitor
suggests about 164 uF for 3 kW. [2652*amps/volts, ie, 2652*13.6/220].
A rule of thumb in www.elcomp.net/conis.pdf suggests 30-50 uF per kW
(for a 220V 50Hz motor) ie 90 to 150 uF for a 3 kW motor. A formula at
https://www.electricneutron.com/elec...ase-capacitor-
sizing/ calls for a power factor number; I didn't calculate that one.

My bad. My old eyes missed the decimal point
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On Tue, 4 Dec 2018 07:39:25 -0600, Terry Coombs
wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?


I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .

The cap in your motor is only connected across one line and neutral,
that's why the 110 volt rating. The very high capacitance is because
the motor is a compressor rated motor and needs the extra torque. I
just went through all this a couple months ago. You really need to
check the starting switch. I guarantee it is easier and cheaper to
replace it with a motor starter if it is the problem. The phenolic
support for the switch in my motor warped which is why I opted the
replace it completely. Electric motors don't usually wear out unless
the windings are really stressed by high current, high voltage, high
temp operating conditions, moisture, etc. Bearings and starter
switches are what usually dies in a single phase electric motor. If
you do decide to replace the motor make sure it is rated for high
torque loads and check the shaft size. Ther is a good chance your
motor has a 25mm shaft, not 1 inch.
Eric
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On 12/4/2018 11:11 AM, wrote:
On Tue, 4 Dec 2018 07:39:25 -0600, Terry Coombs
wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?
I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

Â* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .

The cap in your motor is only connected across one line and neutral,
that's why the 110 volt rating. The very high capacitance is because
the motor is a compressor rated motor and needs the extra torque. I
just went through all this a couple months ago. You really need to
check the starting switch. I guarantee it is easier and cheaper to
replace it with a motor starter if it is the problem. The phenolic
support for the switch in my motor warped which is why I opted the
replace it completely. Electric motors don't usually wear out unless
the windings are really stressed by high current, high voltage, high
temp operating conditions, moisture, etc. Bearings and starter
switches are what usually dies in a single phase electric motor. If
you do decide to replace the motor make sure it is rated for high
torque loads and check the shaft size. Ther is a good chance your
motor has a 25mm shaft, not 1 inch.
Eric


Â* Well , I visited the neighbor , his compressor motor is also a 6 hp
Doerr motor so I borrowed his 189-230something start cap to test . My
motor spun up just fine with the belt off but wouldn't quite go with a
load . So I went to town and bought 2 , one at 243-292 and one at
340-408 . It will start under load with the smaller one , but starts
much better with the big one . It has always been a bit slower to start
when it's really cold out , so I'm going to leave the big one in for now
, try the smaller this summer and see what it does . Total cost to get
'er done was 31 bucks and change , much cheaper than a new motor !

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !



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Default Back in service was : Compressors - kinda on topic !

On Tue, 4 Dec 2018 11:51:13 -0600, Terry Coombs
wrote:

* Well , I visited the neighbor , his compressor motor is also a 6 hp
Doerr motor so I borrowed his 189-230something start cap to test . My
motor spun up just fine with the belt off but wouldn't quite go with a
load . So I went to town and bought 2 , one at 243-292 and one at
340-408 . It will start under load with the smaller one ,


start under load? You dont have an unloader on your compressor???

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Default Compressors - kinda on topic !

On Tue, 4 Dec 2018 07:07:25 -0600, Terry Coombs
wrote:

On 12/4/2018 2:03 AM, James Waldby wrote:
On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?
That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php

The tables at that link appear to only go up to about 1 HP (.746 kW)
and it looks like 80-110 uf is the .373 kW entry in the 220V table,
instead of corresponding to the 6 HP (2.98 kW) Terry mentioned.

A formula at http://homeenergypros.org/profiles/b...ctly-sizing-a-
capacitor
suggests about 164 uF for 3 kW. [2652*amps/volts, ie, 2652*13.6/220].
A rule of thumb in www.elcomp.net/conis.pdf suggests 30-50 uF per kW
(for a 220V 50Hz motor) ie 90 to 150 uF for a 3 kW motor. A formula at
https://www.electricneutron.com/elec...ase-capacitor-
sizing/ calls for a power factor number; I didn't calculate that one.

* I visited the same site as Clare and I think his number is low too .
I don't recall which website I visited that had this formula : current x
10-6th divided by 2 x pi x frequency x voltage , the result of that
formula was 180 mfd ... I'm going over to my blacksmith neighbor's this
morning , he has a compressor very similar to mine . I'll check his
start cap to be sure but I believe the value needed is going to be a
little higher than that due to the high start torque needed for this
application . This is an Emerson/Doerr motor , but I can't find any info
on this specific motor ... it's at least 20 years old and the Emerson
site just burps and says "not found" when I enter the info from the tag
. I believe it's going to be somewhere in the 270-330 mfd range . I may
borrow the cap from the neighbor's compressor to see if it works on mine
since they're very similar . If I can't get it going I'm probably going
to order a new motor , they can be had for around 200 bucks and this one
is pretty old . At this point I've got less than that tied up in this
unit including the original (very used) purchase and parts to rebuild
the pump . Nowhere I know of to get a unit of this size and qualityfor
anywhere near that cheap , including a new motor .


Ive got a 6hp Harbor Freight motor on my old Dvillbiss compressor. Has
worked well for..humm...10+ yrs so far. Its mounted outdoors and it
gets rained on (when we get rain) and its held up quite well. I did
have to replace the start cap last year.

I think I paid somewhere around $100 or less for it then...rack up 10%
for inflation....


Gunner
__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Default Compressors - kinda on topic !

On Tue, 4 Dec 2018 11:06:42 -0400, Leon Fisk
wrote:

On Tue, 4 Dec 2018 07:39:25 -0600
Terry Coombs wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

[...]

I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .


Mine is wired for 110 but can be switched to 220v by moving wires in
the motor. The start cap is 649MFD and 110VAC with a plastic case. The
run cap is in a metal case. So that 110 value maybe okay (shrug). A
picture he

https://i.postimg.cc/J7qVkvJD/DSCF0143.jpg


Many single phase motors are dual voltage. Though I do NOT recommend
starting a 6hp motor on 110vt.....can you say block wide brown out?

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Default Compressors - kinda on topic !

On Tuesday, December 4, 2018 at 8:07:23 AM UTC-5, Terry Coombs wrote:
If I can't get it going I'm probably going
to order a new motor , they can be had for around 200 bucks and this one
is pretty old . At this point I've got less than that tied up in this
unit including the original (very used) purchase and parts to rebuild
the pump . Nowhere I know of to get a unit of this size and qualityfor
anywhere near that cheap , including a new motor .

--
Snag On 12/4/2018 2:03 AM, James Waldby wrote:
On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor . Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?
That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:



If you can wait , I can probably come up with suitable motor or cap.

A few week- ago the scrap yard had 6 or maybe 12 swimming pool motors brand new in original boxes. And 3 phase motor are sometime available in the 50 or 100 hp sises, Smaller are most always available-

Dan
Yes , I'm old
and crochety - and armed .
Get outta my woods !


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Default Compressors - kinda on topic !

On 04/12/2018 20:19, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:06:42 -0400, Leon Fisk
wrote:

On Tue, 4 Dec 2018 07:39:25 -0600
Terry Coombs wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

[...]
I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

Â* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .

Mine is wired for 110 but can be switched to 220v by moving wires in
the motor. The start cap is 649MFD and 110VAC with a plastic case. The
run cap is in a metal case. So that 110 value maybe okay (shrug). A
picture he

https://i.postimg.cc/J7qVkvJD/DSCF0143.jpg

Many single phase motors are dual voltage. Though I do NOT recommend
starting a 6hp motor on 110vt.....can you say block wide brown out?


Maybe in the USA but I've never seen one in the UK or Europe, only 240V
single phase motors as that's what the supply is. The only dual voltage
motors I've seen in the UK are 3 phase and that effects whether they're
wired star or delta. Conceivably construction site motors in the UK
could be dual voltage but that might be illegal, the construction site
motors here are 110V and wired like US split phase wiring with a centre
tapped neutral and each leg at 55V so a shock is deemed non lethal if a
single live is contacted.



__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Default Compressors - kinda on topic !

On 12/4/2018 2:16 PM, Gunner Asch wrote:
On Tue, 4 Dec 2018 07:07:25 -0600, Terry Coombs
wrote:

On 12/4/2018 2:03 AM, James Waldby wrote:
On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
Â* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .Â* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?
That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php
The tables at that link appear to only go up to about 1 HP (.746 kW)
and it looks like 80-110 uf is the .373 kW entry in the 220V table,
instead of corresponding to the 6 HP (2.98 kW) Terry mentioned.

A formula at http://homeenergypros.org/profiles/b...ctly-sizing-a-
capacitor
suggests about 164 uF for 3 kW. [2652*amps/volts, ie, 2652*13.6/220].
A rule of thumb in www.elcomp.net/conis.pdf suggests 30-50 uF per kW
(for a 220V 50Hz motor) ie 90 to 150 uF for a 3 kW motor. A formula at
https://www.electricneutron.com/elec...ase-capacitor-
sizing/ calls for a power factor number; I didn't calculate that one.

Â* I visited the same site as Clare and I think his number is low too .
I don't recall which website I visited that had this formula : current x
10-6th divided by 2 x pi x frequency x voltage , the result of that
formula was 180 mfd ... I'm going over to my blacksmith neighbor's this
morning , he has a compressor very similar to mine . I'll check his
start cap to be sure but I believe the value needed is going to be a
little higher than that due to the high start torque needed for this
application . This is an Emerson/Doerr motor , but I can't find any info
on this specific motor ... it's at least 20 years old and the Emerson
site just burps and says "not found" when I enter the info from the tag
. I believe it's going to be somewhere in the 270-330 mfd range . I may
borrow the cap from the neighbor's compressor to see if it works on mine
since they're very similar . If I can't get it going I'm probably going
to order a new motor , they can be had for around 200 bucks and this one
is pretty old . At this point I've got less than that tied up in this
unit including the original (very used) purchase and parts to rebuild
the pump . Nowhere I know of to get a unit of this size and qualityfor
anywhere near that cheap , including a new motor .

Ive got a 6hp Harbor Freight motor on my old Dvillbiss compressor. Has
worked well for..humm...10+ yrs so far. Its mounted outdoors and it
gets rained on (when we get rain) and its held up quite well. I did
have to replace the start cap last year.

I think I paid somewhere around $100 or less for it then...rack up 10%
for inflation....


Gunner

Â* And your point is ? This is/was a Speedaire , had a cast iron pump on
it but - it was used in a large cabinet shop , way beyond it's duty
rating and the pump fried . I paid a c-note for the tank and motor , put
an Ingersoll-Rand pump I had on it . Aside from having to replace the
con rods because I got stupid , this is the first repair it's ever
needed . It is sheltered , I have more respect for my tools than to
leave them out in the rain .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Default Back in service was : Compressors - kinda on topic !

On 12/4/2018 2:10 PM, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:51:13 -0600, Terry Coombs
wrote:

Â* Well , I visited the neighbor , his compressor motor is also a 6 hp
Doerr motor so I borrowed his 189-230something start cap to test . My
motor spun up just fine with the belt off but wouldn't quite go with a
load . So I went to town and bought 2 , one at 243-292 and one at
340-408 . It will start under load with the smaller one ,

start under load? You dont have an unloader on your compressor???

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Â* Yes of course there's an unloader on it - in fact the tank was empty
this morning . But it was also 26° outside this morning , and there is a
load just from friction and cold oil . This compressor has always
started a little slow in cold weather , sometimes tripping the internal
overload . I usually leave it off unless I need it during the really
cold spells .

--
Snag
Yes , I'm old
and crochety - and armed .
Get outta my woods !

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Default Back in service was : Compressors - kinda on topic !

On Wed, 5 Dec 2018 06:30:23 -0600, Terry Coombs
wrote:

On 12/4/2018 2:10 PM, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:51:13 -0600, Terry Coombs
wrote:

* Well , I visited the neighbor , his compressor motor is also a 6 hp
Doerr motor so I borrowed his 189-230something start cap to test . My
motor spun up just fine with the belt off but wouldn't quite go with a
load . So I went to town and bought 2 , one at 243-292 and one at
340-408 . It will start under load with the smaller one ,

start under load? You dont have an unloader on your compressor???

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


---
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* Yes of course there's an unloader on it - in fact the tank was empty
this morning . But it was also 26° outside this morning , and there is a
load just from friction and cold oil . This compressor has always
started a little slow in cold weather , sometimes tripping the internal
overload . I usually leave it off unless I need it during the really
cold spells .


If its popping the overloads..you dont have them of the proper value.
If its a "contactor" type..increase the trip value (typically a tiny
blue plastic screw). If its a circuit breaker..increase the amps by 10
and retry.

When you said "loaded" I assumed you meant under air pressure. A
compressor/motor is "unloaded" as long as there is no air on the
compressor head(s). Sounds like you have a couple small niggling
issues that need to be addressed along with your major one. You might
also want to change the type/grade of compressor oil to a lighter one.
Mobil One synthetic seems to work well enough as a compressor oil, you
may want to go to a 5 or 10 weight oil. You can get away with using a
"detergent" type motor oil, given how seldom you use your compressor.
Though to be fair..a good synthetic 30 weight is pretty slippery in
and of itself. Given summer temps may get higher...pondering on it..Id
say use Mobil One 30 weight and change the overloads to a higher
value.

Shrug..but what do I know...?

Gunner






__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.

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Default Compressors - kinda on topic !

On Wed, 5 Dec 2018 10:48:30 +0000, David Billington
wrote:

On 04/12/2018 20:19, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:06:42 -0400, Leon Fisk
wrote:

On Tue, 4 Dec 2018 07:39:25 -0600
Terry Coombs wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

[...]
I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .

Mine is wired for 110 but can be switched to 220v by moving wires in
the motor. The start cap is 649MFD and 110VAC with a plastic case. The
run cap is in a metal case. So that 110 value maybe okay (shrug). A
picture he

https://i.postimg.cc/J7qVkvJD/DSCF0143.jpg

Many single phase motors are dual voltage. Though I do NOT recommend
starting a 6hp motor on 110vt.....can you say block wide brown out?


Maybe in the USA but I've never seen one in the UK or Europe, only 240V
single phase motors as that's what the supply is. The only dual voltage
motors I've seen in the UK are 3 phase and that effects whether they're
wired star or delta. Conceivably construction site motors in the UK
could be dual voltage but that might be illegal, the construction site
motors here are 110V and wired like US split phase wiring with a centre
tapped neutral and each leg at 55V so a shock is deemed non lethal if a
single live is contacted.


True indeed for the UK and much of Eurpope.

Since the standard for the colonies is 110vt for house wiring and 220
single phase..most of our motors will be marked this way:

https://stickerdeals.net/wp-content/...ng-diagram.jpg

3 phase motors are labled this way:

https://i.stack.imgur.com/KmuB3.jpg

https://www.hunker.com/12390388/how-...10v-220v-motor

Canada uses the same conventions (for the most part) that the US
does..with a few odd places that use 50 hertz power and 330 volts as I
recall..Canadians... please step in and correct me.

Gunner






__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.

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Default Compressors - kinda on topic !

On Wed, 5 Dec 2018 06:30:16 -0600, Terry Coombs
wrote:

On 12/4/2018 2:16 PM, Gunner Asch wrote:
On Tue, 4 Dec 2018 07:07:25 -0600, Terry Coombs
wrote:

On 12/4/2018 2:03 AM, James Waldby wrote:
On Tue, 04 Dec 2018 00:44:44 -0500, Clare Snyder wrote:
On Mon, 3 Dec 2018 13:53:29 -0600, Terry Coombs ... wrote:
* Well , Mr. Compressor has a case of the humms . That is , when I try
to start it , it just humms (until the O/L cuts it off if I let it go
that long). This is the original motor on an old Speedaire 60 gallon
tank , 220 volts and 3450 RPM's . Specs call for 15 amps full load ,
rated output is 2.98Kw , about 6 hp . This is an Emerson/Doerr
compressor duty motor .* Tested both caps , one is good and the other
isn't according to the tests with my DMM . Problem is that the bad cap
has rubbed the capacitance and voltage ratings off the label . Got a
couple of calls in , looked around on the internet , can't find a
definite answer . I'm pretty sure it needs to be around 250uf and at
least 250 volts - though maybe higher voltage to account for spikes . I
have the motor type/classification numbers , just can't find a reference
to check ... anybody got a lead on that type of info ?
That will be the start cap - 275 volt and 80-100 uf

Don't take my word for it - take a look where I got the info:

https://inspectapedia.com/electric/M..._Selection.php
The tables at that link appear to only go up to about 1 HP (.746 kW)
and it looks like 80-110 uf is the .373 kW entry in the 220V table,
instead of corresponding to the 6 HP (2.98 kW) Terry mentioned.

A formula at http://homeenergypros.org/profiles/b...ctly-sizing-a-
capacitor
suggests about 164 uF for 3 kW. [2652*amps/volts, ie, 2652*13.6/220].
A rule of thumb in www.elcomp.net/conis.pdf suggests 30-50 uF per kW
(for a 220V 50Hz motor) ie 90 to 150 uF for a 3 kW motor. A formula at
https://www.electricneutron.com/elec...ase-capacitor-
sizing/ calls for a power factor number; I didn't calculate that one.

* I visited the same site as Clare and I think his number is low too .
I don't recall which website I visited that had this formula : current x
10-6th divided by 2 x pi x frequency x voltage , the result of that
formula was 180 mfd ... I'm going over to my blacksmith neighbor's this
morning , he has a compressor very similar to mine . I'll check his
start cap to be sure but I believe the value needed is going to be a
little higher than that due to the high start torque needed for this
application . This is an Emerson/Doerr motor , but I can't find any info
on this specific motor ... it's at least 20 years old and the Emerson
site just burps and says "not found" when I enter the info from the tag
. I believe it's going to be somewhere in the 270-330 mfd range . I may
borrow the cap from the neighbor's compressor to see if it works on mine
since they're very similar . If I can't get it going I'm probably going
to order a new motor , they can be had for around 200 bucks and this one
is pretty old . At this point I've got less than that tied up in this
unit including the original (very used) purchase and parts to rebuild
the pump . Nowhere I know of to get a unit of this size and qualityfor
anywhere near that cheap , including a new motor .

Ive got a 6hp Harbor Freight motor on my old Dvillbiss compressor. Has
worked well for..humm...10+ yrs so far. Its mounted outdoors and it
gets rained on (when we get rain) and its held up quite well. I did
have to replace the start cap last year.

I think I paid somewhere around $100 or less for it then...rack up 10%
for inflation....


Gunner

* And your point is ? This is/was a Speedaire , had a cast iron pump on
it but - it was used in a large cabinet shop , way beyond it's duty
rating and the pump fried . I paid a c-note for the tank and motor , put
an Ingersoll-Rand pump I had on it . Aside from having to replace the
con rods because I got stupid , this is the first repair it's ever
needed . It is sheltered , I have more respect for my tools than to
leave them out in the rain .


I was simply saying you can find a cheap decent motor for very little
money. I pick up used ones for $25. Anything single phase over 5hp
will be harder to find and will often be $50-75..simply because of
their scarcity. I was not trying to bust your bubble or insult you
etc.

My "outside" motors tend to be TEFC or OCP type motors. That being
said..we get so little rain here..4-5" a year...that putting a
compressor outdoors with only a small "roof" over them works well
enough. My compressor and tank was built in June, 1964. Its spent
nearly all of its life outdoors and doesn't appear to be harmed in the
slightest. Still has most of the original paint as well.

Your area of course is much different.

Gunner

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Default Back in service was : Compressors - kinda on topic !

On 05/12/2018 20:30, Gunner Asch wrote:
On Wed, 5 Dec 2018 06:30:23 -0600, Terry Coombs
wrote:

On 12/4/2018 2:10 PM, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:51:13 -0600, Terry Coombs
wrote:

Â* Well , I visited the neighbor , his compressor motor is also a 6 hp
Doerr motor so I borrowed his 189-230something start cap to test . My
motor spun up just fine with the belt off but wouldn't quite go with a
load . So I went to town and bought 2 , one at 243-292 and one at
340-408 . It will start under load with the smaller one ,
start under load? You dont have an unloader on your compressor???

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Â* Yes of course there's an unloader on it - in fact the tank was empty
this morning . But it was also 26° outside this morning , and there is a
load just from friction and cold oil . This compressor has always
started a little slow in cold weather , sometimes tripping the internal
overload . I usually leave it off unless I need it during the really
cold spells .

If its popping the overloads..you dont have them of the proper value.
If its a "contactor" type..increase the trip value (typically a tiny
blue plastic screw). If its a circuit breaker..increase the amps by 10
and retry.


It could also be the wrong class of breaker if that's what's tripping.
I've seen motors on lighting rated circuits tripping because the breaker
characteristics are not suited to motor start-up surges even when the
nominal motor current is well below the breaker current. Replacing the
breaker with a suitably rated breaker sorted the issue.



When you said "loaded" I assumed you meant under air pressure. A
compressor/motor is "unloaded" as long as there is no air on the
compressor head(s). Sounds like you have a couple small niggling
issues that need to be addressed along with your major one. You might
also want to change the type/grade of compressor oil to a lighter one.
Mobil One synthetic seems to work well enough as a compressor oil, you
may want to go to a 5 or 10 weight oil. You can get away with using a
"detergent" type motor oil, given how seldom you use your compressor.
Though to be fair..a good synthetic 30 weight is pretty slippery in
and of itself. Given summer temps may get higher...pondering on it..Id
say use Mobil One 30 weight and change the overloads to a higher
value.

Shrug..but what do I know...?

Gunner






__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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Default Back in service was : Compressors - kinda on topic !

On Wed, 5 Dec 2018 21:06:28 +0000, David Billington
wrote:

On 05/12/2018 20:30, Gunner Asch wrote:
On Wed, 5 Dec 2018 06:30:23 -0600, Terry Coombs
wrote:

On 12/4/2018 2:10 PM, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:51:13 -0600, Terry Coombs
wrote:

* Well , I visited the neighbor , his compressor motor is also a 6 hp
Doerr motor so I borrowed his 189-230something start cap to test . My
motor spun up just fine with the belt off but wouldn't quite go with a
load . So I went to town and bought 2 , one at 243-292 and one at
340-408 . It will start under load with the smaller one ,
start under load? You dont have an unloader on your compressor???

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


---
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* Yes of course there's an unloader on it - in fact the tank was empty
this morning . But it was also 26° outside this morning , and there is a
load just from friction and cold oil . This compressor has always
started a little slow in cold weather , sometimes tripping the internal
overload . I usually leave it off unless I need it during the really
cold spells .

If its popping the overloads..you dont have them of the proper value.
If its a "contactor" type..increase the trip value (typically a tiny
blue plastic screw). If its a circuit breaker..increase the amps by 10
and retry.


It could also be the wrong class of breaker if that's what's tripping.
I've seen motors on lighting rated circuits tripping because the breaker
characteristics are not suited to motor start-up surges even when the
nominal motor current is well below the breaker current. Replacing the
breaker with a suitably rated breaker sorted the issue.


Excellent post!

I installed an elderly Cincinatti #2 centerless grinder in a shop a
couple weeks ago. They have (2) motors in them..the 4 hp "regulating
motor" and a 15-25hp Grinding motor. This machine was set up on a
220vt 30 amp breaker..which of couse is half of what the minimum
breaker should be. The moment the big motor came on line..it of
course popped the breakers. When I found the small breakers..I
installed 60 ampers..as most..most of these machines require a minimum
60s. I ampprobed the start up on this motor..and it was 273 AMPS -/+
!!! Run current was 32 amps and only went up and down a couple amps
under a load.

So I had to order a "slow blow" type breaker and I increased the amps
to 70 amps..I had no other choice besides installing a Slow Start box.
I may have to install a slow starter..simply because the rating of
that end of the building is only 200 amps..and it has to share power
with 4 other machines. Walter CNC grinders..so as it stands right
now..they have to power this machine up first..before anything
else...and once its warmed up and running..they can turn on the other
machines. They were not..not amused by this....(Grin)

The machine came from one of my least favorite A list dealers....

Ive seen him sell some really..Iffy machines and have had to fix them
after they were purchased..$adly.

Gunner
__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.

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On Wed, 05 Dec 2018 12:40:05 -0800, Gunner Asch
wrote:

On Wed, 5 Dec 2018 10:48:30 +0000, David Billington
wrote:

On 04/12/2018 20:19, Gunner Asch wrote:
On Tue, 4 Dec 2018 11:06:42 -0400, Leon Fisk
wrote:

On Tue, 4 Dec 2018 07:39:25 -0600
Terry Coombs wrote:

On 12/4/2018 6:43 AM, Leon Fisk wrote:
On Mon, 3 Dec 2018 13:53:29 -0600
Terry Coombs wrote:

[...]
I had a similar problem a few years ago with my Speedaire 20 gallon
2hp. My caps checked out. Ended up cleaning the contacts on the
starting/centrifugal switch. Has been okay since. Take a look at this
pdf file and see it it lists your motor:

https://www.jackssmallengines.com/gr...PREADSHEET.pdf

It had mine in it plus quite a few more...

* Thanks Leon , my motor is listed ! For a 606727 motor - that's what
is on my tag - it calls for a 704 mfd at 110 volts . Hmmm , that doesn't
seem right since this is a 220 volt motor . If doubling the voltage
halves the capacitance needed , a 330-380 mfd cap would seem about right
... I just found a contact link for Emerson , messaged them . We'll see
what they say . I never really thought about how much I use that
compressed air until I don't have it ... and since my ne'er-do-well son
has apparently burned up my small portable for me , I'm kinda in a pinch .

Mine is wired for 110 but can be switched to 220v by moving wires in
the motor. The start cap is 649MFD and 110VAC with a plastic case. The
run cap is in a metal case. So that 110 value maybe okay (shrug). A
picture he

https://i.postimg.cc/J7qVkvJD/DSCF0143.jpg
Many single phase motors are dual voltage. Though I do NOT recommend
starting a 6hp motor on 110vt.....can you say block wide brown out?


Maybe in the USA but I've never seen one in the UK or Europe, only 240V
single phase motors as that's what the supply is. The only dual voltage
motors I've seen in the UK are 3 phase and that effects whether they're
wired star or delta. Conceivably construction site motors in the UK
could be dual voltage but that might be illegal, the construction site
motors here are 110V and wired like US split phase wiring with a centre
tapped neutral and each leg at 55V so a shock is deemed non lethal if a
single live is contacted.


True indeed for the UK and much of Eurpope.

Since the standard for the colonies is 110vt for house wiring and 220
single phase..most of our motors will be marked this way:

https://stickerdeals.net/wp-content/...ng-diagram.jpg

3 phase motors are labled this way:

https://i.stack.imgur.com/KmuB3.jpg

https://www.hunker.com/12390388/how-...10v-220v-motor

Canada uses the same conventions (for the most part) that the US
does..with a few odd places that use 50 hertz power and 330 volts as I
recall..Canadians... please step in and correct me.

Gunner


At one time - pre 1950 +/-, some areas used 25Hz., Voltage was refered
as 120/240 or 110/220 with 208 as common 3Ph.
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On 2018-12-04, Leon Fisk wrote:
On Tue, 4 Dec 2018 07:39:25 -0600
Terry Coombs wrote:


[ ... ]

Mine is wired for 110 but can be switched to 220v by moving wires in
the motor. The start cap is 649MFD and 110VAC with a plastic case. The
run cap is in a metal case. So that 110 value maybe okay (shrug). A
picture he

https://i.postimg.cc/J7qVkvJD/DSCF0143.jpg


At least the start cap should do at 110 VAC even if the motor is
wired for 220 VAC. In that case, the start winding is connected between
the center tap of the two run windings and one end, so it only sees 110
VAC (or 120 VAC depending on local power voltage).

Enjoy,
DoN.

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  #30   Report Post  
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Default Compressors - kinda on topic !

I may have a similar problem with my small lathe. It quit yesterday. Had a
couple slow starts where I pushed it with the collet closer handle to get it
going, and now nothing. The fact that its nothing "not even a hum" mkes me
wonder of the on/direction switch is bad. Fortunately I had radiused just
enough alignment pins for the projects that were finishing yesterday.



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Default Compressors - kinda on topic !

"Bob La Londe" wrote in message
news
I may have a similar problem with my small lathe. It quit yesterday.
Had a couple slow starts where I pushed it with the collet closer
handle to get it going, and now nothing. The fact that its nothing
"not even a hum" mkes me wonder of the on/direction switch is bad.
Fortunately I had radiused just enough alignment pins for the
projects that were finishing yesterday.


I made a short 12 AWG type SO extension cord with some of the outer
insulation removed to diagnose motor problems with a clamp-on ammeter.
It helps to measure how much they draw before they break.


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"Jim Wilkins" wrote in message news
"Bob La Londe" wrote in message
news
I may have a similar problem with my small lathe. It quit yesterday. Had a
couple slow starts where I pushed it with the collet closer handle to get
it going, and now nothing. The fact that its nothing "not even a hum" mkes
me wonder of the on/direction switch is bad. Fortunately I had radiused
just enough alignment pins for the projects that were finishing yesterday.


I made a short 12 AWG type SO extension cord with some of the outer
insulation removed to diagnose motor problems with a clamp-on ammeter.
It helps to measure how much they draw before they break.

****************

All fixed. There was a terminal block on the motor that looked like white
ceramic. When I unscrewed it from the motor case it just disintegrated.
There were two wires that were broken at that point. Its seems that the
terminal block may have been holding them in contact without a good
mechanical connection for some time. I put it back together with (yuck)
butt splices. The wire stubs coming out of the motor were so short nothing
else would work. They were so short I had to use one tool for stripping
with forward strippers and another tool for crimping with forward crimpers.
It works again.


  #33   Report Post  
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Default Compressors - kinda on topic !

On Tue, 11 Dec 2018 09:45:34 -0700, "Bob La Londe"
wrote:

"Jim Wilkins" wrote in message news
"Bob La Londe" wrote in message
news
I may have a similar problem with my small lathe. It quit yesterday. Had a
couple slow starts where I pushed it with the collet closer handle to get
it going, and now nothing. The fact that its nothing "not even a hum" mkes
me wonder of the on/direction switch is bad. Fortunately I had radiused
just enough alignment pins for the projects that were finishing yesterday.


I made a short 12 AWG type SO extension cord with some of the outer
insulation removed to diagnose motor problems with a clamp-on ammeter.
It helps to measure how much they draw before they break.

****************

All fixed. There was a terminal block on the motor that looked like white
ceramic. When I unscrewed it from the motor case it just disintegrated.
There were two wires that were broken at that point. Its seems that the
terminal block may have been holding them in contact without a good
mechanical connection for some time. I put it back together with (yuck)
butt splices. The wire stubs coming out of the motor were so short nothing
else would work. They were so short I had to use one tool for stripping
with forward strippers and another tool for crimping with forward crimpers.
It works again.


Ouch! At least now you have some time to source a replacement. Sounds
like one will be needed at some point.
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"Pete Keillor" wrote in message
...

On Tue, 11 Dec 2018 09:45:34 -0700, "Bob La Londe"
wrote:

"Jim Wilkins" wrote in message news
"Bob La Londe" wrote in message
news
I may have a similar problem with my small lathe. It quit yesterday. Had
a
couple slow starts where I pushed it with the collet closer handle to get
it going, and now nothing. The fact that its nothing "not even a hum"
mkes
me wonder of the on/direction switch is bad. Fortunately I had radiused
just enough alignment pins for the projects that were finishing yesterday.


I made a short 12 AWG type SO extension cord with some of the outer
insulation removed to diagnose motor problems with a clamp-on ammeter.
It helps to measure how much they draw before they break.

****************

All fixed. There was a terminal block on the motor that looked like white
ceramic. When I unscrewed it from the motor case it just disintegrated.
There were two wires that were broken at that point. Its seems that the
terminal block may have been holding them in contact without a good
mechanical connection for some time. I put it back together with (yuck)
butt splices. The wire stubs coming out of the motor were so short nothing
else would work. They were so short I had to use one tool for stripping
with forward strippers and another tool for crimping with forward crimpers.
It works again.


Ouch! At least now you have some time to source a replacement. Sounds
like one will be needed at some point.

***********
Actually I was going to throw a small 3 phase motor on it with a VFD for
more speed control, but I don't have a spare 120V/240V VFD and I don't have
240V handy where that lathe is located. I'll have to put some on my keep
an eye out list.

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On 2018-12-08, Bob La Londe wrote:
I may have a similar problem with my small lathe. It quit yesterday. Had a
couple slow starts where I pushed it with the collet closer handle to get it
going, and now nothing. The fact that its nothing "not even a hum" mkes me
wonder of the on/direction switch is bad. Fortunately I had radiused just
enough alignment pins for the projects that were finishing yesterday.


The lack of hum may be a function of how big a motor, and where
it happens to have stopped.

But given the slow starts, you very likely have let the smoke
out of the start capacitor.

I had that problem with a 1-1/2 HP motor, wired for 120 VAC
operation. Slow starts when belted for high speed, and occasional
tripping of the circuit breaker for that outlet. After it blew I
replaced the starting cap, re-wired the motor and switch for 240 VAC
operation, and connected it to a 240 VAC outlet, and it has worked well
ever since. (Some of these days, I'll swap in a 3-phase motor and a
VFD so I get variable speed as well, without having to shift belts all
the time. :-)

Good Luck,
DoN.

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On 16 Dec 2018 02:38:14 GMT, "DoN. Nichols"
wrote:

On 2018-12-08, Bob La Londe wrote:
I may have a similar problem with my small lathe. It quit yesterday. Had a
couple slow starts where I pushed it with the collet closer handle to get it
going, and now nothing. The fact that its nothing "not even a hum" mkes me
wonder of the on/direction switch is bad. Fortunately I had radiused just
enough alignment pins for the projects that were finishing yesterday.


The lack of hum may be a function of how big a motor, and where
it happens to have stopped.

But given the slow starts, you very likely have let the smoke
out of the start capacitor.

I had that problem with a 1-1/2 HP motor, wired for 120 VAC
operation. Slow starts when belted for high speed, and occasional
tripping of the circuit breaker for that outlet. After it blew I
replaced the starting cap, re-wired the motor and switch for 240 VAC
operation, and connected it to a 240 VAC outlet, and it has worked well
ever since. (Some of these days, I'll swap in a 3-phase motor and a
VFD so I get variable speed as well, without having to shift belts all
the time. :-)

Good Luck,
DoN.



I've got a DC motor and speed control I've been promising myself I'll
install on my Myford Super Seven some day - It's been gathering dust
beside the lathe for several years now - - -
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"DoN. Nichols" wrote in message
...

On 2018-12-08, Bob La Londe wrote:
I may have a similar problem with my small lathe. It quit yesterday. Had
a
couple slow starts where I pushed it with the collet closer handle to get
it
going, and now nothing. The fact that its nothing "not even a hum" mkes
me
wonder of the on/direction switch is bad. Fortunately I had radiused just
enough alignment pins for the projects that were finishing yesterday.


The lack of hum may be a function of how big a motor, and where
it happens to have stopped.

But given the slow starts, you very likely have let the smoke
out of the start capacitor.

I had that problem with a 1-1/2 HP motor, wired for 120 VAC
operation. Slow starts when belted for high speed, and occasional
tripping of the circuit breaker for that outlet. After it blew I
replaced the starting cap, re-wired the motor and switch for 240 VAC
operation, and connected it to a 240 VAC outlet, and it has worked well
ever since. (Some of these days, I'll swap in a 3-phase motor and a
VFD so I get variable speed as well, without having to shift belts all
the time. :-)

*****************
Actually there were some bad connections at a little terminal block on the
motor. The terminal block looked like white ceramic, but crumbled like
dried paste. There were actually two wires that were no longer connected
when I lifted the crumbling block of paste away from the motor. There was
so little wire sticking out of the motor the only way to repair the was to
use butt splices. I had to use front cutting wire strippers, and front
crimping crimpers.

Next time it fails my plan (like you) is to throw a small 3 phase motor on
the lathe with a VFD. To keep it 110V I'll use one of those little 1HP 110V
in 220V out Hitachis (or similar). Its got a 3/4 hp motor on it now. Its
so old the motor was made in Taiwan, not China. In fact its so old it says
Repubic of China. I hve a couple 3/4HP 3phase motoros on the shelf I picked
up somewhere that would do. A 2 pole and a 4 pole. Figured the 4 pole
would be ideal. I've never really had a power issue on that small lathe.
The rigidity of the machine limits me somewhat. I want to keep it 110V
because Its a finished wall where I plan to leave the machine, and I don't
have 220V to that location.

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Default Compressors - kinda on topic !

replying to Bob La Londe, David H.T. Jordan wrote:
I have that motor! It has a 189-227uf 220vac cap from Aerovox and a 15uf 370v
cap from Aeromet. I hope this helps some one someday. Mopar Dave, Turner
Electric Motor Service, Las Cruces, NM 88005

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for full context, visit https://www.polytechforum.com/metalw...ic-647335-.htm


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