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Terry Coombs[_2_] December 3rd 18 07:53 PM

Compressors - kinda on topic !
 
* 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 ?

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


[email protected] December 3rd 18 09:54 PM

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 ?

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

Terry Coombs[_2_] December 3rd 18 10:08 PM

Compressors - kinda on topic !
 
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 .

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


Gunner Asch[_6_] December 3rd 18 11:10 PM

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.


---
This email has been checked for viruses by Avast antivirus software.
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[email protected] December 4th 18 12:44 AM

Compressors - kinda on topic !
 
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

?B?Z1NieG7impvihpAg4pWsIPCdkbTwnZKK8J2SiPCdkonwnZKV8J2SmiDwnZG+?=?B?8J2SgvCdko/wnZKP8J December 4th 18 01:38 AM

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









Clare Snyder December 4th 18 05:44 AM

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

James Waldby[_3_] December 4th 18 08:03 AM

Compressors - kinda on topic !
 
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.

--
jiw

Leon Fisk[_2_] December 4th 18 12:43 PM

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 ?



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


Terry Coombs[_2_] December 4th 18 01:07 PM

Compressors - kinda on topic !
 
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 .

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



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