too much voltage fluctuation for CNC

[lesmar96]

Good Morning,

customer with a CNC router in a woodworking facility. The power off of the pole is fluctuating too much and the CNC is giving codes of high voltage. No surprise, when they say they are seeing from 448 - 502 on the incoming power. Their CNC shuts down once or twice a day because of this.

Their power company allows +/- 10% which they are still within spec that way so I doubt the power company will bat an eye about it. I have heard of equipment that will monitor the incoming power and switch transformers on and off and different taps to keep the outgoing voltage steady. Has any one else had success with equipment of that style? something like this https://www.schneider-electric.us/e.../63377-surevolt-™automatic-voltage-regulator/

Or is there a better solution??

 

[jrwb4gbm]

I've been retired for several years, so, I really don't know the latest technology. Try googling sola transformers constant voltage. Maybe you can find something.

 

[James Mcquade]

+1 for constant voltage transformers.

 

[Lynx777]

I've seen this problem before at a place with 4 CNC router machines. They would get errors for high and low voltage, memory corruption and every time a storm came through at least one of the machines would get a fried control board. In my case the problem ended up being a poor neutral to ground connection at the service entrance, combined with a poor ground rod installation.

You are correct about the power company, but with a little "squeaking" they should be willing to come out and check all the connections on the service entrance and transformers. After that is done, check all of the power and ground connections from the service entrance all the way to the CNC machines. Lastly, check the connections going out to the ground rod and have the ground rod tested by someone who TRULY understands how to do it.

Again, in my case the ground rod installation was not good. The soil was very poor electrically. I ended up installing a grid of 10 ground rods to get the resistance down to acceptable levels.

After the neutral and ground problems were fixed they never had another problem. At least for the couple of years that I was still there.

One last thought. Make sure no one has installed an isolated ground rod on any of the machines. In the "good old days" some people used to think that an isolated ground rod was a must, but I can tell you from experience that it is dangerous and will cause more problems than it will fix.

Hope this helps.

 

[rdrast]

+1 for constant voltage transformers.

CVT's would be ideally applied for this problem, but put a disconnect in front of it, and shut it off when not in use. CVT's use a non-insignificant amount of power even at idle.