# Looking for advice: Enco step pulley Mill with 2 speed motor + VFD



## cathead (Jan 5, 2015)

I have a 1995 model Enco 9x42 step pulley mill with a 2 speed 220 volt 3 phase motor. 
It has been a great mill but the electrical switch has gone bad so am giving some
consideration to installing a VFD unit.  I think the motor is a 2 horse unit so am 
wondering if this motor ( 2 speed) will work with a 3hp VFD.  Also I have heard that
there might be voltage spikes with the VFD and the possibility that my motor might
arc out inside.  I would gladly try a VFD if I don't have to replace the motor and do
major surgery here.  Also it this looks like it would be possible, would one want to
use the high or low speed winding in the motor?  Another thing that I am wondering
about is that most of the VFD units are keypad operated.  Do they have some
provision for using a variable resistor to control the speed?  It is quite difficult
to get the information I am looking for from sales ads on EBAY.  I have asked
a lot of questions so expect there will be some reverberation and difference
of opinion, which will be welcome of course.    Thank you.


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## 18w (Jan 5, 2015)

I have a Teco vfd on my 2hp Bridgeport. Works fantastic. It has a potentiometer knob to adjust the frequency though I never use it much since mine is a varispeed. Bought it from Automation Direct. I am sure they can steer you in the right direction. If you have a competent motor rebuilder near by I am sure they could fill you in regarding your 2 speed motor requirements. I found you do not have to oversize your vfd. 2hp vfd for 2hp motor is adequate...2 speed motor may be different. Lots of ways to wire in your vfd with remote control, braking capability, and so forth. I never bothered but I am a analog guy in a digital world. I know some people at a local motor shop that could answer your questions regarding your 2 speed motor. Pm me if you like and I will give you names and a phone number. There is a ton of vfd info on a couple of the other forums. just enter vfd in your search and have lots of time.

Regards
Darrell

Sorry double post just tried to edit bad spelling


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## JimDawson (Jan 5, 2015)

The VFD won't hurt your motor.  In 25 or so years I have never seen one fail from voltage spikes.  I am running VFDs on a number of older motors.

Most VFD can be operated from a remotely mounted control station, you just have to set up the programming and wire in the controls.  Most come out of the box set up for the keypad.  Normally it's just a couple of parameters that you have to set.

I would connect to the low speed windings.  That will give you more torque (4 pole vs 2 pole).  You can run the VFD up to 120 Hz to get the high speed.  You might want to go with a 3hp VFD if you want to do this, to be sure to handle the extra load.


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## rdhem2 (Jan 6, 2015)

Unless I missed something, is your original motor three phase?  Has to be to use a VFD.  After that you may do as you wish.  All things you mention are available.  Myself I like and use Sq D/Telemecinique, Allan Bradley, or Hitachi drives.  Stay away from the China crap.  Have fun!


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## Doubleeboy (Jan 6, 2015)

If it is any help, I have a 10 year old 2HP Jet JTM-1 with 2 speed 3 ph motor.  I use a 3HP Teco Westinghouse FM50 I believe and it works fine...... but I have to let it warm up for a minute or so on one of the lower pulley speeds before I can crank up to the highest speed settings.  Doesn't really cause me any trouble 90% of the work I do is under 1200 rpm.  If I set to a high speed pulley and have the motor in high to start the day I will get a fault on the VFD.  Change the speeds with the belt and let it warm up for a minute at lower speed and it works fine.  As I do not have inverter rated motor, I do not run below 40 hz except for just a few seconds when power tapping.

michael


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## cathead (Jan 6, 2015)

rdhem2 said:


> Unless I missed something, is your original motor three phase?  Has to be to use a VFD.  After that you may do as you wish.  All things you mention are available.  Myself I like and use Sq D/Telemecinique, Allan Bradley, or Hitachi drives.  Stay away from the China crap.  Have fun!



The motor is 3 phase, Russ.  I'm presently running it with phase generative
capacitors.  It looks like I am about ready to go VFD shopping.


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## cathead (Jan 6, 2015)

Doubleeboy said:


> If it is any help, I have a 10 year old 2HP Jet JTM-1 with 2 speed 3 ph motor.  I use a 3HP Teco Westinghouse FM50 I believe and it works fine...... but I have to let it warm up for a minute or so on one of the lower pulley speeds before I can crank up to the highest speed settings.  Doesn't really cause me any trouble 90% of the work I do is under 1200 rpm.  If I set to a high speed pulley and have the motor in high to start the day I will get a fault on the VFD.  Change the speeds with the belt and let it warm up for a minute at lower speed and it works fine.  As I do not have inverter rated motor, I do not run below 40 hz except for just a few seconds when power tapping.
> 
> michael



I just ordered a TECO FM50 203C (Westinghouse) which is 230 in single phase and 3 phase out and rated for 3 horsepower.  

At this point am considering some sort of enclosure as it will be in the
vicinity of the mill with flying chips and all.  This will be an interesting project.


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