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

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

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

5 hp 3 phase motor to a 3/4 hp single phase..?
 

Where are you?

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

5 hp 3 phase motor to a 3/4 hp single phase..?
 

From: "Paul"



Any ideas?
Other than that pulleys perhaps?

I wouldn't recommend using a rigid sleeve. It makes alignment too critical.
Use something like a Lovejoy flexible coupling. You can get one end with the
5/8 bore and one end with the 1 1/8 bore and a neoprene spider to go in the
middle. That way it only takes a few minutes to bolt them together and line
them up without having to get the two shafts in perfect alignment.

Richard Coke

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

5 hp 3 phase motor to a 3/4 hp single phase..?
 

I'll have to try that.

Reno, Paul

"Richard Coke" wrote in message
...
From: "Paul"



Any ideas?
Other than that pulleys perhaps?

I wouldn't recommend using a rigid sleeve. It makes alignment too
critical.
Use something like a Lovejoy flexible coupling. You can get one end with
the
5/8 bore and one end with the 1 1/8 bore and a neoprene spider to go in
the
middle. That way it only takes a few minutes to bolt them together and
line
them up without having to get the two shafts in perfect alignment.

Richard Coke

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

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

5 hp 3 phase motor to a 3/4 hp single phase..?
 

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

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

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.

5 hp 3 phase motor to a 3/4 hp single phase..?
 

In article ,
says...
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?


Depends on what you mean by "instant". I have the VFD on my
mill set to accel and decel from base speed (60Hz) in 1
second and the speed range limited to 6Hz to 90Hz. That
means you can drill at, for instance, 1000RPM then dial the
speed down to power tap at 100RPM. The mill will take 1 sec
to stop from 1000RPM (60 - 0 Hz), but will do a full
reversal in .2 sec at 100RPM (6 - 0 - -6 Hz).

Ned Simmons

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

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

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.

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

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

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

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

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

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

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

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

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

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
==================================================

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

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

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

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

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

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