What would you say, can one run a 230/440v motor that is 45 years old,
from a VFD.

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

i

Ignoramus8727 wrote:

What would you say, can one run a 230/440v motor that is 45 years old,
from a VFD.

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

i

My Bridgeport is a lot more than 45 years old, and I've not had a
problem running it's 220/440 motor on the VFD.

Ignoramus8727 wrote:
What would you say, can one run a 230/440v motor that is 45 years old,
from a VFD.

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

Given your proclivity for this sort of thing, you ought to be smart enough
to just move.
Yeah, it's a pain but so what?
Make your life look like your end game, or desires.


--
John R. Carroll

On Tue, 19 Jan 2010 17:04:47 -0600, Ignoramus8727
wrote:

What would you say, can one run a 230/440v motor that is 45 years old,
from a VFD.

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

i


Only you will be able to determine this by actually running your motor
from a VFD

Gunner

The current Democratic party has lost its ideological basis for
existence.
- It is NOT fiscally responsible.
- It is NOT ethically honorable.
- It has started wars based on lies.
- It does not support the well-being of americans - only billionaires.
- It has suppresed constitutional guaranteed liberties.
- It has foisted a liar as president upon America.
- It has violated US national sovereignty in trade treaties.
- It has refused to enforce the national borders.

....It no longer has valid reasons to exist.
Lorad474

On 2010-01-20, Paul Hovnanian P.E. wrote:
Ignoramus8727 wrote:

What would you say, can one run a 230/440v motor that is 45 years old,
from a VFD.

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

Two things to consider:
1) Cooling at low RPMs. Not a big deal if all you are doing is producing
3 phase at or near lie frequency.

I do not need to change frequency on this lathe.

I just wanted to not have to run the phase converter.

Right now the lathe runs off of a phase-a-matic static converter box,
but that is not too good for the motor, and does not give me the full
HP.

2) Effects of HF harmonics on windings and rotor. This is a bit trickier
to guess about. Some motors need their rotors grounded (through a slip
ring or something similar) to prevent HF coupling from the stator to the
rotor from returning to ground through the bearings. That can erode
them.

This is kind of my issue right here.

i

Ignoramus8727 wrote:

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

Given your ability to find a deal, is there any reason you can't come up with a rpc? I'm
running mine on a Rotophase my uncle found in a dumpster at a oil location he maintained
portapotties at. A motor, a few caps, you are good go to.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

On 2010-01-20, Wes wrote:
Ignoramus8727 wrote:

I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.

I would really like to run this lathe from a VFD as opposed to the
phase converter.

Given your ability to find a deal, is there any reason you can't come up with a rpc? I'm
running mine on a Rotophase my uncle found in a dumpster at a oil location he maintained
portapotties at. A motor, a few caps, you are good go to.

I already have a phase converter, but I was hoping I would not need to
use it for the lathe. I have a pile of variable frequency drives, some
are in a bad cosmetic shape (hard to sell) that are quite usable.

i

Ignoramus29895 wrote:

Given your ability to find a deal, is there any reason you can't come up with a rpc? I'm
running mine on a Rotophase my uncle found in a dumpster at a oil location he maintained
portapotties at. A motor, a few caps, you are good go to.

I already have a phase converter, but I was hoping I would not need to
use it for the lathe. I have a pile of variable frequency drives, some
are in a bad cosmetic shape (hard to sell) that are quite usable.

i

I don't know enough about VFD's in your application to help you.

It would seem that a motor that is 230/460 which I belive yours in could handle whatever
extra strain a vfd would put on it.

I don't know but would adding some load side capacitance mellow out how your motor reacts?
I'm hoping our EE's on the list have comments on that one.

Wes



--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

On 2010-01-20, Wes wrote:
Ignoramus29895 wrote:

Given your ability to find a deal, is there any reason you can't come up with a rpc? I'm
running mine on a Rotophase my uncle found in a dumpster at a oil location he maintained
portapotties at. A motor, a few caps, you are good go to.

I already have a phase converter, but I was hoping I would not need to
use it for the lathe. I have a pile of variable frequency drives, some
are in a bad cosmetic shape (hard to sell) that are quite usable.

i

I don't know enough about VFD's in your application to help you.

It would seem that a motor that is 230/460 which I belive yours in could handle whatever
extra strain a vfd would put on it.

I don't know but would adding some load side capacitance mellow out how your motor reacts?
I'm hoping our EE's on the list have comments on that one.


I am pretty sure that you cannot put capacitors on the output of a
VFD.

Actually right now, the lathe is on a Phase-A-Matic static phase
converter. The Phase-A-Matic came with the lathe. It runs, but I am
getting only 2 HP out of 3. Maybe I should just leave it as is. I
would not be likely to use all of the HP without coolant.

I want to do the right thing, and it is not immediately obvious what
is the right thing. I know for sure that I do not need to vary input
frequency.

It seems that the phase converter route is nicest to the motor, and
lathe, but is less convenient for me.

i

"Ignoramus29895" wrote in message
...
On 2010-01-20, Wes wrote:
Ignoramus29895 wrote:

I am pretty sure that you cannot put capacitors on the output of a
VFD.

Correct, VFD PWM output is designed for inductive load usually a V/F
ratio based on the rpm your vfd is set at. Capacitors placed on
the output will change the pulse width and could cause the motor
to overheat at less than 60Hz settings. In addition you will be
creating a LC circuit with its own set of problems that VFD's
don't like. You might end up with a multi kilowatt AM transmitter
of sorts.

Best Regards
Tom.

On Wed, 20 Jan 2010 16:57:41 -0600, Ignoramus29895
wrote:

On 2010-01-20, Wes wrote:
Ignoramus29895 wrote:

Given your ability to find a deal, is there any reason you can't come up with a rpc? I'm
running mine on a Rotophase my uncle found in a dumpster at a oil location he maintained
portapotties at. A motor, a few caps, you are good go to.

I already have a phase converter, but I was hoping I would not need to
use it for the lathe. I have a pile of variable frequency drives, some
are in a bad cosmetic shape (hard to sell) that are quite usable.

i

I don't know enough about VFD's in your application to help you.

It would seem that a motor that is 230/460 which I belive yours in could handle whatever
extra strain a vfd would put on it.

I don't know but would adding some load side capacitance mellow out how your motor reacts?
I'm hoping our EE's on the list have comments on that one.


I am pretty sure that you cannot put capacitors on the output of a
VFD.

Actually right now, the lathe is on a Phase-A-Matic static phase
converter. The Phase-A-Matic came with the lathe. It runs, but I am
getting only 2 HP out of 3. Maybe I should just leave it as is. I
would not be likely to use all of the HP without coolant.

I want to do the right thing, and it is not immediately obvious what
is the right thing. I know for sure that I do not need to vary input
frequency.

It seems that the phase converter route is nicest to the motor, and
lathe, but is less convenient for me.

i

There's now way of being sure but the odds are pretty good.

VFDs increase the peak voltage stresses on the motor insulation,
Most older motors survive (all that I have used) but a few fail.
Capacitors do NOT help.

The yard stick I would use is simply based on the mechanics
of the motor installation. If it's difficult or impossible to
replace it with a modern motor then it makes sense to stick with
an RPC.

If on the other hand it's a fairly standard motor that
could be replaced if disaster struck I would chose the VFD drive
on the basis that the increased convenience outweighs the small
increase in risk.

Jim

On Jan 20, 4:49*pm, Wes wrote:
Ignoramus8727 wrote:
I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.
....
Given your ability to find a deal,

You could add an insulation tester (Megger) to your search list:
http://www.testequipmentdepot.com/me...FZdM5QodwCMZzg

The hand-cranked ones are safer because they shut off if you get a zap
and stop cranking, plus you can check old motors on the shelf without
needing AC power.

If you find two real cheap, I could use one.

jsw

On 2010-01-21, wrote:
On Wed, 20 Jan 2010 16:57:41 -0600, Ignoramus29895
wrote:
Actually right now, the lathe is on a Phase-A-Matic static phase
converter. The Phase-A-Matic came with the lathe. It runs, but I am
getting only 2 HP out of 3. Maybe I should just leave it as is. I
would not be likely to use all of the HP without coolant.

I want to do the right thing, and it is not immediately obvious what
is the right thing. I know for sure that I do not need to vary input
frequency.

It seems that the phase converter route is nicest to the motor, and
lathe, but is less convenient for me.

There's now way of being sure but the odds are pretty good.

Great

VFDs increase the peak voltage stresses on the motor insulation,
Most older motors survive (all that I have used) but a few fail.
Capacitors do NOT help.

Jim, do inductors help? Those line reactors, would a line reactor help
if I installed one between the drive and the motor?

The yard stick I would use is simply based on the mechanics
of the motor installation. If it's difficult or impossible to
replace it with a modern motor then it makes sense to stick with
an RPC.

It is not very special. Here's a picture.

http://igor.chudov.com/projects/Clau...arage-0017.jpg

Looks like 184T to me, but could be an old frame size due to it having
been made in 1966.

If on the other hand it's a fairly standard motor that
could be replaced if disaster struck I would chose the VFD drive
on the basis that the increased convenience outweighs the small
increase in risk.

I also like Jim Wilkins' suggestion of trying to test insulation with a
megger. This would be my first time of using a megger. I believe I
have one from my old military surplus days.

i

On 2010-01-21, Jim Wilkins wrote:
On Jan 20, 4:49?pm, Wes wrote:
Ignoramus8727 wrote:
I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.
...
Given your ability to find a deal,

You could add an insulation tester (Megger) to your search list:
http://www.testequipmentdepot.com/me...FZdM5QodwCMZzg

The hand-cranked ones are safer because they shut off if you get a zap
and stop cranking, plus you can check old motors on the shelf without
needing AC power.

If you find two real cheap, I could use one.

Jim, I thought I had a megger, thisi s a GREAT idea and I will try
it. I would say that if insulation can survive 800v, I should be fine.

i

azotic wrote:
"Ignoramus29895" wrote in message
...
On 2010-01-20, Wes wrote:
Ignoramus29895 wrote:

I am pretty sure that you cannot put capacitors on the output of a
VFD.

Correct, VFD PWM output is designed for inductive load usually a V/F
ratio based on the rpm your vfd is set at. Capacitors placed on
the output will change the pulse width and could cause the motor
to overheat at less than 60Hz settings. In addition you will be
creating a LC circuit with its own set of problems that VFD's
don't like. You might end up with a multi kilowatt AM transmitter
of sorts.

But you can put inductance in series with the
output to dampen the harmonics. Don't know the
specifics concerning Iggy's VFD, but I've seen
it done on pump station VFD's in a residential
neighborhood.

On Thu, 21 Jan 2010 08:23:01 -0600, Ignoramus18274
wrote:

On 2010-01-21, wrote:
On Wed, 20 Jan 2010 16:57:41 -0600, Ignoramus29895
wrote:
Actually right now, the lathe is on a Phase-A-Matic static phase
converter. The Phase-A-Matic came with the lathe. It runs, but I am
getting only 2 HP out of 3. Maybe I should just leave it as is. I
would not be likely to use all of the HP without coolant.

I want to do the right thing, and it is not immediately obvious what
is the right thing. I know for sure that I do not need to vary input
frequency.

It seems that the phase converter route is nicest to the motor, and
lathe, but is less convenient for me.

There's now way of being sure but the odds are pretty good.

Great

VFDs increase the peak voltage stresses on the motor insulation,
Most older motors survive (all that I have used) but a few fail.
Capacitors do NOT help.

Jim, do inductors help? Those line reactors, would a line reactor help
if I installed one between the drive and the motor?

The yard stick I would use is simply based on the mechanics
of the motor installation. If it's difficult or impossible to
replace it with a modern motor then it makes sense to stick with
an RPC.

It is not very special. Here's a picture.

http://igor.chudov.com/projects/Clau...arage-0017.jpg

Looks like 184T to me, but could be an old frame size due to it having
been made in 1966.

If on the other hand it's a fairly standard motor that
could be replaced if disaster struck I would chose the VFD drive
on the basis that the increased convenience outweighs the small
increase in risk.

I also like Jim Wilkins' suggestion of trying to test insulation with a
megger. This would be my first time of using a megger. I believe I
have one from my old military surplus days.


Line reactors are useful because they slow the rise time of
the transients but, unless you've long cable runs, the effect is
not large. It's probably not worth buying a set but if you
happen to have one on hand you might as well fit them.

A megger test is certainly helpful but even that doesn't give
you full assurance. It's a very long time since I signed off
equipment but the test yardstick in those days was twice peak
working voltage plus 1000V.

Jim

Ignoramus29895 wrote:

I don't know but would adding some load side capacitance mellow out how your motor reacts?
I'm hoping our EE's on the list have comments on that one.


I am pretty sure that you cannot put capacitors on the output of a
VFD.


Sorry. It was late, my brain wasn't in gear. I have a severe head cold.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

Ignoramus8727 wrote:
What would you say, can one run a 230/440v motor that is 45 years old,
from a VFD.

I ran a Bridgeport M-head motor off a VFD. The
crummy less-than first
generation VFD eventually smoked when I tried plug
reversing the motor.
That motor worked SO MUCH better off a VFD than a
static phase converter it
was amazing. The motor was, I'm sure, the
original 1938 motor on that
mill.
I had a bad experience running a 230v only motor of a similar vintage,
due to current leakage. The 440v motors, though, have better
insulation.
Yes, the motor I mention above was a 230/460 V
unit. I am also running
a 1950's vintage J-head motor on a VFD now, and it
also works fine. So, it
also pretty much qualifies for your 45 year old
question. I have run it
for well over 10 years on a VFD with no problems.
This is the Bridgeport
"pancake" motor on 1 Hp step-pulley mills,
single-speed 230/460 V.

Jon

Wes wrote:


I don't know but would adding some load side capacitance mellow out how your motor reacts?
I'm hoping our EE's on the list have comments on that one.
No, you do NOT want to put capacitors on the
output side of a VFD. The VFD
produces 400 V square waves of varying duty cycle,
to create the right currents
in the motor windings. Capacitors will draw huge
currents on the edges of those
square waves, and either fry themselves or the
transistors in the VFD. You can
cobble up an L-C filter if you really feel the
need, but it shouldn't be nexessary
in most cases. Old motors run in a moist
environment might be more susceptible
to insulation breakdown, so if you are running
machines in an unheated garage, that
might be more of a concern.

Jon

Ignoramus29895 wrote:

Actually right now, the lathe is on a Phase-A-Matic static phase
converter. The Phase-A-Matic came with the lathe. It runs, but I am
getting only 2 HP out of 3. Maybe I should just leave it as is. I
would not be likely to use all of the HP without coolant.

I want to do the right thing, and it is not immediately obvious what
is the right thing. I know for sure that I do not need to vary input
frequency.

It seems that the phase converter route is nicest to the motor, and
lathe, but is less convenient for me.
I don't know, these just run the motor on single
phase once started,
I think that may also be hard on the motor. Also,
a properly set-up
VFD can give you dynamic braking, which can be
real nice on a lathe
with a big chuck (unless the lathe has a
mechanical clutch-brake
mechanism).

Jon

On 2010-01-22, Jon Elson wrote:
Ignoramus29895 wrote:

Actually right now, the lathe is on a Phase-A-Matic static phase
converter. The Phase-A-Matic came with the lathe. It runs, but I am
getting only 2 HP out of 3. Maybe I should just leave it as is. I
would not be likely to use all of the HP without coolant.

I want to do the right thing, and it is not immediately obvious what
is the right thing. I know for sure that I do not need to vary input
frequency.

It seems that the phase converter route is nicest to the motor, and
lathe, but is less convenient for me.

I don't know, these just run the motor on single phase once started,
I think that may also be hard on the motor. Also, a properly set-up
VFD can give you dynamic braking, which can be real nice on a lathe
with a big chuck (unless the lathe has a mechanical clutch-brake
mechanism).

It has a clutch/brake. I have decided to use a VFD. Right now I am
busy cleaning this lathe. It already looks better.

i