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Author Topic: Spindle revs out of control  (Read 2488 times)

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Spindle revs out of control
« on: December 18, 2008, 04:36:49 PM »
Need Help
My wabeco lathe spindle goes max speed no matter what i set it at.
before this happened it was going about 500 revs above programed and after a few seconds would go to programed speed

Dave

Offline KTM

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Re: Spindle revs out of control
« Reply #1 on: December 20, 2008, 01:16:27 AM »
Hi Dave

Do you have a AC motor spindle or a servo spindle?
Check your VFD reference voltage (0-10v) or in the case of a servo check the encoder.

Regards

KTM

Offline jimpinder

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Re: Spindle revs out of control
« Reply #2 on: December 20, 2008, 03:52:35 AM »
As KTM says, you do not say what system of control your machne uses. I had trouble with mine, which uses the PWM signal through a digispeed - giving a 0 - 10v signal to an Omron Inverter.

The trouble is each part of the system depends on the one before being spot on. I managed to buy an oscilloscope - which ran through my PC. This was extremely cheap - about £30. It will monitor two channels, on a range of 0 - 15 volts input.

With it, I could trace the signal coming out of the PC (PWM) and right through the system up to the Digispeed. I don't have a breakout board as such, but the changes in polarity going through some breakout boards are difficult to trace.

With an oscilloscope, you can see the waveform change as you put in S commands. I eventually found the PWM signal was inverted when it reached the Inverter. This meant that when the spindle switched on it went to full speed, instead of staying still, and never did get to the proper speed.

I soon got it sorted out, and it works fine now. (Apologies to our friend in Australia if I gave the idea there was something wrong with the Digispeed.)  
Not me driving the engine - I'm better looking.
Re: Spindle revs out of control
« Reply #3 on: December 20, 2008, 02:47:18 PM »
My motor is 230 volt ac 0-5000 revs.  The drive board is Combo 5
lack of electronic knowlege doesnt help
where do i check the VFD voltage
Re: Spindle revs out of control
« Reply #4 on: December 20, 2008, 04:03:03 PM »
If this a Bob Campbell combo board ver.5 just download the manual
and follow the instructions.You may have to read through a few times and
google terms you are unfamiliar with.