V.F.D. on a mill?

[Scotts]

Originally Posted by GWIZ

I'm cheap,
Is there anything wrong with placing the VFD on wheels and using the same ONE for all the machinery ?
One machine at A time.

I'm cheap as well, I would use velcro on the back of the unit and on several spots on the wall where I wanted to use it.

Scott

[precisionworks]

Is there anything wrong with placing the VFD on wheels and using the same ONE for all the machinery ? One machine at A time.

Benefits - you save $200-$300 per machine.

Drawbacks:

It gets mounted on a cart of some type, which takes a fair amount of space. Or on a two wheeler which is easily tipped over. Or it gets put down somewhere that it can (and will) get knocked off.

You can't use machine controls for Fwd/Stop/Rev, speed, etc. Which means you always have to use the keypad. All machine controls, like a drum switch on a lathe or mill, are nonfunctional - which is a pretty backward way to set up a machine tool.

If you left the machine controls in place & disconnect the motor from the drive under power, you'll damage the drive. Some fail on the first attempt, some go for a while, but it's only a matter of time before the drive is nonfunctional. They do, however, make an interesting paper weight

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This topic comes up at least once a week on the electronic control forums where I post. Consensus from the EE's and ME's is that it's cheaper to have one drive per machine, wired in so that the machine's drum switch is used to command the VFD to Fwd/Stop/Rev plus a speed pot for remote speed control.

[kvom]

Another issue is the settings. Generally you need to enter the motor parameters, and unless every machine has the same motor switching would be a major hassle.

[precisionworks]

waiting delivery of my Hitachi SJ200

I have one Hitachi drive and three SMVector drives. Hitachi builds a nice drive but changing parameters is a pain ... first you have to go into the A Group - Standard Functions, then the H Group - Motor Constants Functions, and finally the B Group - Fine Tuning Functions. Switching from A to B to H is a challenge, and I end up calling tech support at Hitachi for help. Page 9 in this doc explains the process, and includes a "keypad navigation map":

http://www.hitachi-america.us/suppor...G_NB6501XA.pdf

The Teco EV drives are much easier to set, but still take a little getting used to. See Page 17 in this doc:

http://www.tecowestinghouse.com/Manu...ing_manual.pdf

The most user friendly of all is the SMVector. Scroll through the numbers from 100 to 500 and make changes as needed. No map required

[Bolt]

I just installed an DuraPulse 20 HP drive from http://www.automationdirect.com/adc/...alog/AC_Drives I installed a 30 HP drive of their's 2 years ago. Yes, there are allot of parameters, but you can make a drive do almost anything you want it to. Also, with the DuraPulse, you can save 4 different groups of settings to the keypad, and then download them at once, so if you do run it on a different motor, you can just save it all to the keypad and switch fairly quick. You can also swap keypads between drives for backups, etc.

The DuraPulse is a very inexpensive drive, and quite capable. They also have even cheaper lines, the GS1 and GS2 drives, less features, lower HP, probably perfect for shop tools.

You could also wire the controls to a plug, then you can unplug those from the machine when switching. But, I would still favor a drive per machine, unless you really don't use it too often.

[slim]

I am looking at this thread and no one has mentioned that VFD put out pulses and that can be double the line voltage. I just completed a VFD course and one of the things is was brought out is that you should only use a VFD rated motor on a VFD. I am a industrial electrician and I know from experience that a standard motor will not last long in VFD service.
Slim

[randy_m]

How long is not long? And whats the differance?

[GWIZ]

http://www.shopfloortalk.com/forums/...76&postcount=9

http://www.shopfloortalk.com/forums/...46&postcount=4

[precisionworks]

I am a industrial electrician and I know from experience that a standard motor will not last long in VFD service.

Every Made in USA motor (Baldor, Leeson, etc.) uses 600 volt magnet wire on their 240 volt motors. I've never heard of a 240 volt VFD driven motor that failed because of insulation burn through. At 480 volts or above, there is a chance that a VFD will induce insulation failure, but we run a number of 480v drives at work without a hitch - and have done so for over 10 years.

you should only use a VFD rated motor on a VFD.

Most manufacturers market a motor that they call a "Vector Drive Motor". Strangely enough, NEMA (National Electrical Manufacturers Assn) has yet to define what constitutes a motor suitable for freq drive. The general consensus among the electrical engineers with whom I network is that the most suitable motor type is a TENV (totally enclosed non ventilated). The TENV design is as bulletproof as can be, and they can be run 24/7/365 under the most hostile conditions. If I had to pick one motor for VFD use, especially at 480 volts or above, the TENV would be first choice. Every "VFD rated motor" or vector drive motor is a TENV.

For motors operating at 240 volts, just about any motor of high quality will last for decades, as will the drive.

[randy_m]

precisionworks,

Thats what I thought. We have at least a 100 vfd's here at work and rarely have to change a drive or a motor for electrical issues, most the time the motors just plain wore out and shot. So on a mill I would think my leeson motor would last me a life time. (tenv of coarse) I'll only run it mabey 20 hrs. a month.