Yaskawa speed control doesn't power on.

I have an Alpha PRS about 10 years old. I've had issues with starting the CNC for a long time. On initial startup the control software (3.8.42) would state the reset on the remote pendant needs to be reset. It would not. After a few hours of sitting idle, the error would go away and all would work properly. The quick fix was to leave the machine powered on.

Well fast forward several years with only turning the control box off once in a while. This last cycle when turning on the control box, the spindle fan comes on, push reset on the pendant switch to power on the VFD and nothing. Yaskawa VFD 10250.

My question is where do I start to look?

Feel free to ask more questions if needed.

Thanks, Tracy

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Originally Posted by tracys

My question is where do I start to look?

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Power is not being transferred to the VFD. Look at the power contactors which are the big black/grey blocks in the control box. One side is power in, other is power out. Use your meter to check that you are getting power out. If not, the contactors are shot. You can get replacements from SB.

FYI - They are electro-magnetic and usually fail when ambient starts heating up since the coils overheat and get weak. You *may* be able to assist the gray part of the magnetic contactor so it transfers power...Just be sure to be safe when you're in there probing around or you'll get a surprise...