Strange VFD problem

I've fitted Mitsubishi S520S VFDs to my mill: a 0.75Kw for the main drive and 0.4Kw for the table drive. Both have been in use for almost 2 years. A few days ago the table drive suddenly stopped - I had been using it, on and off, for about 2 hours with no problems when it suddenly stopped. The VFD frequency showed 0.0 and no errors. If I switched the motor on, the "Run" light blinked but nothing else happened - the motor wouldn't run. I switched all power off, waited a short while, and tried again, but got the same result. I finished the job over the next few days by manually winding the table. I retried the power drive from time to time, with no success. The job is now finished so I cleaned the mill up and started to look for the fault: the first thing I did was to try again - and it worked! I have no idea what the fault was (is?) so can't really fix it. Anyone got any ideas?

Reply to
lemel_man
Loading thread data ...

Are you running an external speed control pot on the VFD? If so, I would change it as it's the most likely culprit. Martin

Reply to
Martin Whybrow

Thanks Martin, I am using a pot and that was the component I was going to check first, but now its working again I can't check it. I'll get another one as a spare and wait for the problem to recur.

Reply to
lemel_man

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.