Need Help!- Spindle Drive Problem

[Zoni]

Hi every one I have the drive and motor are of kollmorgen / inland motors

Machine : Harding Lathe
Model: CHNC4
Spindle Drive: HPA03-158100-611-5306B35
Serial : 4M-405
Spindle Motor: TTBH5306-425-B
Serial No.: 84K72-275

The Problem is that motor is giving a humming noise and at high speed there is vibration. We have checked the motor by giving external power Motor is fine no sound. Then we checked the current input of spindle drive. the Voltage are same but the current varies alot on one wire it reads 25 amps, second it is 12 amp and third is 2 amp. can you suggest please where the problem lies and its solution. thanks its is urgent

[underthetire]

Did you check the Tach on the motor? Sounds like a tach feedback problem to me.

[Zoni]

thanks for quick reply. what is needed to be checked in tacho (I have seen it, physically it is in good condition). do you think tacho can cause the huge difference in current input.

[cnc_guru_guy]

I'd check line to line resistance of the motor. Disconnect all three motor wires and measure resistance from 1 to 2, 2 to 3, and 1 to 3. Should all be around a few ohms. If one is much different than the other then there could be a problem with the motor coils.

Also check each line to GND. If one leg is shorted or has a low resistance to GND it will pull more current than the other legs.

[underthetire]

Yes I do. if it's not getting a stable feedback, the drive will try to adjust the current to maintain constant speed. This usually ends up in blows transistors, as the drive will work too hard. A old analog meter is about the best to use to check it. Just watch for voltage fluctuations at a constant speed.

[Zoni]

Originally Posted by cnc_guru_guy I'd check line to line resistance of the motor. Disconnect all three motor wires and measure resistance from 1 to 2, 2 to 3, and 1 to 3. Should all be around a few ohms. If one is much different than the other then there could be a problem with the motor coils. Also check each line to GND. If one leg is shorted or has a low resistance to GND it will pull more current than the other legs.

Hi, I think you misunderstood me. I am attaching the drawing of the machine. if you see spindle drive and connection strip P01. we connected a variable DC power supply to 4 and 5 and increased the voltage and motor worked fine without a sound or vibration. then we checked the current on 8,9 and 10. there it shows the variation in current

[Zoni]

Hi, I have checked the techo and it is working fine. I removed the wire of reverse SCR. The problem of sound was solved but there was still difference in phase current from transformer. Now if I remove the wire from reverse direction motor wont stop instantly. any suggestions