Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
Paul
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Well I gave up on finding a cheap 3 phase motor today and bought a new one.
I paid $172 out the door with a 2 year warranty (5 hp). Its a Chinese model
but hey
they company I bought it from said it was good and all the mining companies
around
here use them all the time. So I guess I will find out! At some point
during today I
ran out of "I am willing to drive around forever to find...cheap." Anyhow
next in
line I've got to connect this to a pony 3/4 horse single phase motor that I
have...
to use as a starter. Any ideas? The 5 hp motor has a 1 1/8" spindle and the
other
has a 5/8" spindle. I think I might try to make a sleeve to attach them end
to end.
Other than that pulleys perhaps? But that might take up a bunch of room.
Anyhow that's where I'm at.

Reno, Paul


  #2   Report Post  
Wayne
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Just use a start capacitor they are only about $15.00. You can just use a
momentary push switch. It will take less time to set up than a piggy back
motor and be allot cleaner. If you want to you could even order some run
capacitors from www.surpluscenter.com
that will work nice
http://www.surpluscenter.com/sort.as...04031618191050


  #3   Report Post  
j.b. miller
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

I've got about 30 , 3Ph 10 HP and smaller motors for free....just to haul
them away...
now if i HAD 3Ph in the shop...

so, a good deal yes, but looks like a trip to the scappies once the snow
stops coming down....

j


  #4   Report Post  
Wayne
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Where are you?


  #5   Report Post  
Brian Lawson
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Hey J.B.,

Where are you located, and what voltages do you have?

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXXX
On Tue, 16 Mar 2004 19:34:58 -0500, "j.b. miller"
wrote:

I've got about 30 , 3Ph 10 HP and smaller motors for free....just to haul
them away...
now if i HAD 3Ph in the shop...

so, a good deal yes, but looks like a trip to the scappies once the snow
stops coming down....

j




  #7   Report Post  
Pete Logghe
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

"Paul" wrote in message ...
Well I gave up on finding a cheap 3 phase motor today and bought a new one.
I paid $172 out the door with a 2 year warranty (5 hp). Its a Chinese model
but hey
they company I bought it from said it was good and all the mining companies
around
here use them all the time. So I guess I will find out! At some point
during today I
ran out of "I am willing to drive around forever to find...cheap." Anyhow
next in
line I've got to connect this to a pony 3/4 horse single phase motor that I
have...
to use as a starter. Any ideas? The 5 hp motor has a 1 1/8" spindle and the
other
has a 5/8" spindle. I think I might try to make a sleeve to attach them end
to end.
Other than that pulleys perhaps? But that might take up a bunch of room.
Anyhow that's where I'm at.

Reno, Paul



For a 5 horse motor, ALL you need to get it started is a small
starting capacitor... About $5.00 worth. New.
Someone else will chime in, but I would go with about 500 mfd. 370 volt.

It's not too critical. The start button adds the starting capacitor.
When you take your finger off the starting button, it is no longer
connected.
The 5 horse motor wil snap up to speed. No sweat. Really.

Forget the pony motor.

Pete
  #9   Report Post  
Paul
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

How would that be wired?

Reno, Paul




For a 5 horse motor, ALL you need to get it started is a small
starting capacitor... About $5.00 worth. New.
Someone else will chime in, but I would go with about 500 mfd. 370 volt.

It's not too critical. The start button adds the starting capacitor.
When you take your finger off the starting button, it is no longer
connected.
The 5 horse motor wil snap up to speed. No sweat. Really.

Forget the pony motor.

Pete



  #10   Report Post  
Derstine
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Paul,
First thing is go to the wiring plate on your motor and group the wires
together for 220 voltage. You will be left with three groups to be wired to
the incoming source, your 220 line. One leg of your 220 connects to anyone
of the three of your motor, the other leg will connect any of the other 3.
For the third leg you will need to split off of one leg of the 220 wires.
From there it goes into one side of the start Capacitor out the other side,
into the push button switch and into the third wire of your motor. When you
start your motor you push the push button and a split second later turn on
the power switch and the motor will spin right up. Then after a 1/2 second
let go of the push button. Works like a charm. That's the down and dirty
method. Do a google search on 3 phase converters and you will find more
info than you know what to do with.
Jerry



"Paul" wrote in message
...
How would that be wired?

Reno, Paul




For a 5 horse motor, ALL you need to get it started is a small
starting capacitor... About $5.00 worth. New.
Someone else will chime in, but I would go with about 500 mfd. 370 volt.

It's not too critical. The start button adds the starting capacitor.
When you take your finger off the starting button, it is no longer
connected.
The 5 horse motor wil snap up to speed. No sweat. Really.

Forget the pony motor.

Pete







  #11   Report Post  
Paul Amaranth
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

(Pete Logghe) wrote in message . com...
"Paul" wrote in message ...
Well I gave up on finding a cheap 3 phase motor today and bought a new one.
I paid $172 out the door with a 2 year warranty (5 hp). Its a Chinese model
but hey
they company I bought it from said it was good and all the mining companies
around
here use them all the time. So I guess I will find out! At some point
during today I
ran out of "I am willing to drive around forever to find...cheap." Anyhow
next in
line I've got to connect this to a pony 3/4 horse single phase motor that I
have...
to use as a starter. Any ideas? The 5 hp motor has a 1 1/8" spindle and the
other
has a 5/8" spindle. I think I might try to make a sleeve to attach them end
to end.
Other than that pulleys perhaps? But that might take up a bunch of room.
Anyhow that's where I'm at.

Reno, Paul



For a 5 horse motor, ALL you need to get it started is a small
starting capacitor... About $5.00 worth. New.
Someone else will chime in, but I would go with about 500 mfd. 370 volt.

It's not too critical. The start button adds the starting capacitor.
When you take your finger off the starting button, it is no longer
connected.
The 5 horse motor wil snap up to speed. No sweat. Really.

Forget the pony motor.

Pete


5hp is way too small to bother with a pony, a 20 hp, maybe.

A higher voltage start cap wouldn't hurt. They make a real mess when
they blow up. If you add run caps, go for higher voltage and make
sure they don't use PCBs. I've had one or two run caps blow up as
well (which is an even bigger mess than the start caps - they just
start on fire)

Personally, I prefer to run low voltage, or at least low current
through the push buttons and use contactors to switch the caps in and
out. You can get a pretty good arc disconnecting the start cap.

It is good practice to put in a contactor that drops out and
disconnects all loads if the power drops. Perhaps not absolutely
necessary, but it could save you if Murphy is having a fun day.

Your motor is probably 3750 rpm. They work, but I'm not convinced
newer motors make better phase converters. I even managed to burn up
one 5hp unit and I think the 7.5 hp one I have now is starting to get
toasted. Probably time to drag out the meters and figure out how much
power is being wasted and retune accordingly.

Check out Hanrahan's article for wiring diagrams.

BTW, I got a 780 rpm 20 hp motor for $10 for the new shop. Now that
was a deal :-) For that, I'll probably use a pony and add in an old
computer to monitor and autotune it by switching in run caps as
needed. That's a ways off.

Paul
  #12   Report Post  
Gary Coffman
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul" wrote:
Anyhownext in
line I've got to connect this to a pony 3/4 horse single phase motor that I have...
to use as a starter. Any ideas? The 5 hp motor has a 1 1/8" spindle and the
other has a 5/8" spindle. I think I might try to make a sleeve to attach them end
to end.
Other than that pulleys perhaps? But that might take up a bunch of room.
Anyhow that's where I'm at.


I wouldn't bother with a pony for a 5 hp converter. Just capacitor start it.
Using a pony starts making sense when you get up into the large converter
range, to reduce starting surge, but for a little 5 hp, capacitor starting is
fine.

Gary
  #13   Report Post  
Peter T. Keillor III
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

Well I gave up on finding a cheap 3 phase motor today and bought a new one.
I paid $172 out the door with a 2 year warranty (5 hp). Its a Chinese model
but hey
they company I bought it from said it was good and all the mining companies
around
here use them all the time. So I guess I will find out! At some point
during today I
ran out of "I am willing to drive around forever to find...cheap." Anyhow
next in
line I've got to connect this to a pony 3/4 horse single phase motor that I
have...
to use as a starter. Any ideas? The 5 hp motor has a 1 1/8" spindle and the
other
has a 5/8" spindle. I think I might try to make a sleeve to attach them end
to end.
Other than that pulleys perhaps? But that might take up a bunch of room.
Anyhow that's where I'm at.

Reno, Paul


I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor
  #14   Report Post  
Brian Lawson
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor



Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.
  #16   Report Post  
Peter T. Keillor III
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor



Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.


Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor
  #17   Report Post  
Bob Swinney
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one you
propose. Though I've not tried reversing with a VFD, I believe the smaller
the power rating of the VFD, the longer it would take to reverse a 3-phase
motor.

Bob Swinney
"Peter T. Keillor III" wrote in message
...
On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor



Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.


Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor



  #18   Report Post  
Jim Stewart
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Bob Swinney wrote:
Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one you
propose. Though I've not tried reversing with a VFD, I believe the smaller
the power rating of the VFD, the longer it would take to reverse a 3-phase
motor.


Based on my limited experience, it's based more on
the stored energy in the drivetrain and the braking
ability of the VFD. The VFD has to eat the energy
that it takes to stop the drivetrain so a little
VFD and a massive, fast drivetrain takes a long time
to stop without the VFD faulting.

  #19   Report Post  
Peter T. Keillor III
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Thu, 18 Mar 2004 18:34:08 -0600, "Bob Swinney"
wrote:

Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one you
propose. Though I've not tried reversing with a VFD, I believe the smaller
the power rating of the VFD, the longer it would take to reverse a 3-phase
motor.

Bob Swinney


Just curious, what do you use instantaneous, as opposed to fast,
reversing for in machining (I'm still a newbie)? Also, is there any
electrical downside to really fast reversing on either a converter or
vfd? I have a L-00 spindle, so I'm not overly concerned with sending
the chuck across the floor.

Regards,

Pete


"Peter T. Keillor III" wrote in message
.. .
On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor


Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.


Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor



  #20   Report Post  
Bob Swinney
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Peter sez: " Just curious, what do you use instantaneous, as opposed to
fast,
reversing for in machining (I'm still a newbie)? Also, is there any
electrical downside to really fast reversing on either a converter or
vfd? I have a L-00 spindle, so I'm not overly concerned with sending
the chuck across the floor."


Mine was intended to be a commentary on reversing, in general, not an
indicator of any particular preference. Personally, I have no need for
reversing other than that which occurs when the machine coasts down to a
gentle stop. I am told some use "fast reversing" for power tapping on a
vertical mill. IMO, power tapping is yet another incursion of technology
into one of the last realms of craftsmanship.

Bob Swinney




  #21   Report Post  
Gunner
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Thu, 18 Mar 2004 16:51:52 -0800, Jim Stewart
wrote:

Bob Swinney wrote:
Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one you
propose. Though I've not tried reversing with a VFD, I believe the smaller
the power rating of the VFD, the longer it would take to reverse a 3-phase
motor.


Based on my limited experience, it's based more on
the stored energy in the drivetrain and the braking
ability of the VFD. The VFD has to eat the energy
that it takes to stop the drivetrain so a little
VFD and a massive, fast drivetrain takes a long time
to stop without the VFD faulting.


Thats what braking resistors are for, to dump that hysterisis current
into. A standard Hardinge lathe, with a 5 hp motor added, running an
8" chuck, will go from 3000 rpm to 3000 rpm in about 3 seconds with a
good 5hp vfd and proper braking resistor.

Just be damned sure you have a camlock chuck ...when the threated
types unscrew at those speeds..it can get realllllllly interesting.

Gunner

"As physicists now know, there is some nonzero probability that any object will,
through quantum effects, tunnel from the workbench in your shop to Floyds Knobs,
Indiana (unless your shop is already in Indiana, in which case the object will
tunnel to Trotters, North Dakota).
The smaller mass of the object, the higher the probability.
Therefore, disassembled parts, particularly small ones,
of machines disappear much faster than assembled machines."
Greg Dermer: rec.crafts.metalworking
  #22   Report Post  
Gunner
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Thu, 18 Mar 2004 20:08:07 -0600, "Bob Swinney"
wrote:

Peter sez: " Just curious, what do you use instantaneous, as opposed to
fast,
reversing for in machining (I'm still a newbie)? Also, is there any
electrical downside to really fast reversing on either a converter or
vfd? I have a L-00 spindle, so I'm not overly concerned with sending
the chuck across the floor."


Mine was intended to be a commentary on reversing, in general, not an
indicator of any particular preference. Personally, I have no need for
reversing other than that which occurs when the machine coasts down to a
gentle stop. I am told some use "fast reversing" for power tapping on a
vertical mill. IMO, power tapping is yet another incursion of technology
into one of the last realms of craftsmanship.

Bob Swinney

I use fast reversing for tapping on my Gorton Mastermil, which has a
HEAVY spindle, and on the various lathes here in my hope shop.

Most production shops use fast reversing for CNC lathe tapping, wobble
broaching, and for cut off (gang tooled machines with the cut off tool
on the back side.

Gunner

"As physicists now know, there is some nonzero probability that any object will,
through quantum effects, tunnel from the workbench in your shop to Floyds Knobs,
Indiana (unless your shop is already in Indiana, in which case the object will
tunnel to Trotters, North Dakota).
The smaller mass of the object, the higher the probability.
Therefore, disassembled parts, particularly small ones,
of machines disappear much faster than assembled machines."
Greg Dermer: rec.crafts.metalworking
  #23   Report Post  
Peter T. Keillor III
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Fri, 19 Mar 2004 05:04:59 GMT, Gunner
wrote:

On Thu, 18 Mar 2004 20:08:07 -0600, "Bob Swinney"
wrote:

Peter sez: " Just curious, what do you use instantaneous, as opposed to
fast,
reversing for in machining (I'm still a newbie)? Also, is there any
electrical downside to really fast reversing on either a converter or
vfd? I have a L-00 spindle, so I'm not overly concerned with sending
the chuck across the floor."


Mine was intended to be a commentary on reversing, in general, not an
indicator of any particular preference. Personally, I have no need for
reversing other than that which occurs when the machine coasts down to a
gentle stop. I am told some use "fast reversing" for power tapping on a
vertical mill. IMO, power tapping is yet another incursion of technology
into one of the last realms of craftsmanship.

Bob Swinney

I use fast reversing for tapping on my Gorton Mastermil, which has a
HEAVY spindle, and on the various lathes here in my hope shop.

Most production shops use fast reversing for CNC lathe tapping, wobble
broaching, and for cut off (gang tooled machines with the cut off tool
on the back side.

Gunner

snip big sig

Thanks, Gunner. So it's a primarily a production technique.

Pete
  #24   Report Post  
Brian Lawson
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Hey Peter,

OK. Thanks for that test. I'll do a cost analysis against what I was
thinking about doing.

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXX
On Thu, 18 Mar 2004 17:11:21 -0500, Peter T. Keillor III
wrote:

On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

BIG SNIP

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor


  #25   Report Post  
Brian Lawson
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Hey Bob,

Yep. My thought was that the VFD would drive the rotary converter,
and the question was whether doing an "instant reverse" of lathe or
mill would give the VFD an undesirable spike. Seems to me I had heard
that somewhere here on RCM some time back. I either have to come up
with a "pony drive" or use a VFD to get the 25HP idler cranked up to
speed. I dunno. Maybe a VFD to ramp it up, then switch the VFD out
of the circuit??

My first choice would have been for a maybe 10 HP motor, but elevators
seem to jump that power range. The 25 was close, available, and
shipped here, all free! so I guess that's what I'll use. Hmmm..
I've got a "soft-start" system. I wonder if that will function like a
VFD. I know I'd have to do some cheating because it has a built in
reverse/low phase sensor.

Take care.

Brian Lawson,
Bothwell, Ontario,.
XXXXXXXXXXXXXXX
On Thu, 18 Mar 2004 18:34:08 -0600, "Bob Swinney"
wrote:

Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one you
propose. Though I've not tried reversing with a VFD, I believe the smaller
the power rating of the VFD, the longer it would take to reverse a 3-phase
motor.

Bob Swinney
"Peter T. Keillor III" wrote in message
.. .
On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor


Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.


Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor





  #26   Report Post  
Bob Swinney
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Brian,

If you are planning to use a VFD to start your rotary converter then
reversing is not an issue. Rotarys always run in the same direction, i.e.,
that direction in which they are started. IMO there would be very little
effect "felt" back at the VFD whenever a load machine connected to the
rotary phase converter is reversed. Sorry, but I have no expertise with
VFDs. I can only imagine a VFD could be a way to start your 25 HP idler ---
however, it would seem to be an expensive proposition to use a VFD in that
fashion. A VFD rated for 25 HP would be adequate to directly operate the
load machine(s), I would think. IMO, a pony drive is your best bet. Get
some local electrical "talent" to help with the pony arrangement.

Bob Swinney

"Brian Lawson" wrote in message
...
Hey Bob,

Yep. My thought was that the VFD would drive the rotary converter,
and the question was whether doing an "instant reverse" of lathe or
mill would give the VFD an undesirable spike. Seems to me I had heard
that somewhere here on RCM some time back. I either have to come up
with a "pony drive" or use a VFD to get the 25HP idler cranked up to
speed. I dunno. Maybe a VFD to ramp it up, then switch the VFD out
of the circuit??

My first choice would have been for a maybe 10 HP motor, but elevators
seem to jump that power range. The 25 was close, available, and
shipped here, all free! so I guess that's what I'll use. Hmmm..
I've got a "soft-start" system. I wonder if that will function like a
VFD. I know I'd have to do some cheating because it has a built in
reverse/low phase sensor.

Take care.

Brian Lawson,
Bothwell, Ontario,.
XXXXXXXXXXXXXXX
On Thu, 18 Mar 2004 18:34:08 -0600, "Bob Swinney"
wrote:

Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I

have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would

guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one

you
propose. Though I've not tried reversing with a VFD, I believe the

smaller
the power rating of the VFD, the longer it would take to reverse a

3-phase
motor.

Bob Swinney
"Peter T. Keillor III" wrote in message
.. .
On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor


Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.

Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor





  #27   Report Post  
Gunner
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Fri, 19 Mar 2004 07:18:16 -0500, Peter T. Keillor III
wrote:

On Fri, 19 Mar 2004 05:04:59 GMT, Gunner
wrote:

On Thu, 18 Mar 2004 20:08:07 -0600, "Bob Swinney"
wrote:

Peter sez: " Just curious, what do you use instantaneous, as opposed to
fast,
reversing for in machining (I'm still a newbie)? Also, is there any
electrical downside to really fast reversing on either a converter or
vfd? I have a L-00 spindle, so I'm not overly concerned with sending
the chuck across the floor."

Mine was intended to be a commentary on reversing, in general, not an
indicator of any particular preference. Personally, I have no need for
reversing other than that which occurs when the machine coasts down to a
gentle stop. I am told some use "fast reversing" for power tapping on a
vertical mill. IMO, power tapping is yet another incursion of technology
into one of the last realms of craftsmanship.

Bob Swinney

I use fast reversing for tapping on my Gorton Mastermil, which has a
HEAVY spindle, and on the various lathes here in my hope shop.

Most production shops use fast reversing for CNC lathe tapping, wobble
broaching, and for cut off (gang tooled machines with the cut off tool
on the back side.

Gunner

snip big sig

Thanks, Gunner. So it's a primarily a production technique.

Pete


Yup..but..when tapping, and you will G tap on the mill sooner or
later..its right handy.

Im making a couple sets of QC tool holder posts and blocks for myself
and a friend. Im nearly done, and each holder has (24) 1/4-20 clamp
screw holes. I just finished 8 of them G

One drill bit, one tap, fast reverse. Worked like a champ and I was
only a couple hours doing it all. Doing that by hand...and Id still
be at it G

The center column of the tool holder..the part that attaches to the
lathe cross slide, were all drilled and tapped on the lathe as well,
using quick reverse. Floating tap holder in the tailstock.

The VFD really pays for itself on jobs like this.

Gunner

"As physicists now know, there is some nonzero probability that any object will,
through quantum effects, tunnel from the workbench in your shop to Floyds Knobs,
Indiana (unless your shop is already in Indiana, in which case the object will
tunnel to Trotters, North Dakota).
The smaller mass of the object, the higher the probability.
Therefore, disassembled parts, particularly small ones,
of machines disappear much faster than assembled machines."
Greg Dermer: rec.crafts.metalworking
  #28   Report Post  
jim rozen
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

In article , Gunner says...

One drill bit, one tap, fast reverse. Worked like a champ and I was
only a couple hours doing it all. Doing that by hand...and Id still
be at it G


Alternative approach, Procunier tapping head. Backs out at twice
the speed it goes in. Nice.

I myself plug reverse and brake my converter-driven machines
all the time.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

  #29   Report Post  
Paul
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Well I was able to purchase a 480 MFD 250 volt capacitor is that
the right size? Which btw was 25$

Reno, Paul


  #30   Report Post  
Jerry Martes
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?


Paul

If you E-mail me I'll show you how to wire the rotary converter and the
start capacitor.

Jerry M



"Paul" wrote in message
...
Well I was able to purchase a 480 MFD 250 volt capacitor is that
the right size? Which btw was 25$

Reno, Paul






  #31   Report Post  
Brian Lawson
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

Hey Bob,

Actually, my thoughts exactly. I've got a 1HP pony motor ready, just
need to do the physical work to get it all operational.

Thanks.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXX
On Fri, 19 Mar 2004 09:55:18 -0600, "Bob Swinney"
wrote:

Brian,

If you are planning to use a VFD to start your rotary converter then
reversing is not an issue. Rotarys always run in the same direction, i.e.,
that direction in which they are started. IMO there would be very little
effect "felt" back at the VFD whenever a load machine connected to the
rotary phase converter is reversed. Sorry, but I have no expertise with
VFDs. I can only imagine a VFD could be a way to start your 25 HP idler ---
however, it would seem to be an expensive proposition to use a VFD in that
fashion. A VFD rated for 25 HP would be adequate to directly operate the
load machine(s), I would think. IMO, a pony drive is your best bet. Get
some local electrical "talent" to help with the pony arrangement.

Bob Swinney

"Brian Lawson" wrote in message
.. .
Hey Bob,

Yep. My thought was that the VFD would drive the rotary converter,
and the question was whether doing an "instant reverse" of lathe or
mill would give the VFD an undesirable spike. Seems to me I had heard
that somewhere here on RCM some time back. I either have to come up
with a "pony drive" or use a VFD to get the 25HP idler cranked up to
speed. I dunno. Maybe a VFD to ramp it up, then switch the VFD out
of the circuit??

My first choice would have been for a maybe 10 HP motor, but elevators
seem to jump that power range. The 25 was close, available, and
shipped here, all free! so I guess that's what I'll use. Hmmm..
I've got a "soft-start" system. I wonder if that will function like a
VFD. I know I'd have to do some cheating because it has a built in
reverse/low phase sensor.

Take care.

Brian Lawson,
Bothwell, Ontario,.
XXXXXXXXXXXXXXX
On Thu, 18 Mar 2004 18:34:08 -0600, "Bob Swinney"
wrote:

Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I

have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would

guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one

you
propose. Though I've not tried reversing with a VFD, I believe the

smaller
the power rating of the VFD, the longer it would take to reverse a

3-phase
motor.

Bob Swinney
"Peter T. Keillor III" wrote in message
.. .
On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor


Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.

Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor




  #32   Report Post  
Gary Coffman
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Fri, 19 Mar 2004 15:11:44 -0800, "Paul" wrote:
Well I was able to purchase a 480 MFD 250 volt capacitor is that
the right size? Which btw was 25$


The voltage rating is too low. It needs to be at least 340 volts.
That's the peak voltage (sqrt(2) * 240) it'll have to stand in use.
A 370 volt capacitor would give you a little safety margin for the
days your line voltage is high.

Gary
  #33   Report Post  
news.qwest.net
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?


Actually if you are on 240 single phase and get the right VFD ( AB 1336 for
example ) it will convert the single phase to tree phase. But the catch is
about a 50% HP reduction so you have to get a 5 hp VFD for a 3hp motor.

Tom



"Brian Lawson" wrote in message
...
Hey Bob,

Yep. My thought was that the VFD would drive the rotary converter,
and the question was whether doing an "instant reverse" of lathe or
mill would give the VFD an undesirable spike. Seems to me I had heard
that somewhere here on RCM some time back. I either have to come up
with a "pony drive" or use a VFD to get the 25HP idler cranked up to
speed. I dunno. Maybe a VFD to ramp it up, then switch the VFD out
of the circuit??

My first choice would have been for a maybe 10 HP motor, but elevators
seem to jump that power range. The 25 was close, available, and
shipped here, all free! so I guess that's what I'll use. Hmmm..
I've got a "soft-start" system. I wonder if that will function like a
VFD. I know I'd have to do some cheating because it has a built in
reverse/low phase sensor.

Take care.

Brian Lawson,
Bothwell, Ontario,.
XXXXXXXXXXXXXXX
On Thu, 18 Mar 2004 18:34:08 -0600, "Bob Swinney"
wrote:

Brian,
The "speed" of reversing a 3-phase motor would be a function of how stiff
the 3-phase source is. A genuine 3-phase line being the quickest. I have
done this and it is hard to tell when stop-then- reverse occurs. It is
about as close as you can get to instantaneous. Following, I would guess,
is a good stiff, balanced, rotary phase converter such as the 25 HP one you
propose. Though I've not tried reversing with a VFD, I believe the smaller
the power rating of the VFD, the longer it would take to reverse a 3-phase
motor.

Bob Swinney
"Peter T. Keillor III" wrote in message
.. .
On Thu, 18 Mar 2004 07:51:58 -0500, Brian Lawson
wrote:

On Thu, 18 Mar 2004 06:55:28 -0500, Peter T. Keillor III
wrote:

On Tue, 16 Mar 2004 15:57:06 -0800, "Paul"
wrote:

SNIP

I like vfd's, but wouldn't argue with the guys building converters
from low cost or free motors. But for that price, I would have gone
for a vfd.

Pete Keillor


Hey peter,

I thought there was at least some controversy about being able to do
"instant" reversals with a VFD attached. Any comments from anybody?

This comment/question from somebody who hopes to be starting a 25HP as
a rotary convertor some day pretty soon.

Take care.

Brian Lawson,
Bothwell, Ontario.


Brian, I don't know about instant, but you can do 'em pretty quick.
It depends on how you program the accel and decel times. I don't need
fast, so I set mine for 10 seconds. When I flip from forward to
reverse, the motor decelerates to a stop, then instantly changes
direction and accelerates in reverse.

Update: I just went in the shop and programmed 1 sec. accel - decel
times. It changes direction damn quick.

Pete Keillor





  #34   Report Post  
Gary Coffman
 
Posts: n/a
Default 5 hp 3 phase motor to a 3/4 hp single phase..?

On Tue, 23 Mar 2004 11:00:48 -0600, "news.qwest.net" wrote:
Actually if you are on 240 single phase and get the right VFD ( AB 1336 for
example ) it will convert the single phase to tree phase. But the catch is
about a 50% HP reduction so you have to get a 5 hp VFD for a 3hp motor.


Or you can use a TECO brand VFD to drive a 3 hp motor without derating.
(TECO VFDs don't require derating when operated off 1 ph until the load
goes above 3 hp).

Gary
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