Need help! Voltage not right on Bridgeport Series II

[AlexBandar]

Hello all,

I just bought a Bridgeport CNC Mill Series II from a friend of mine. It was working fine when he had it; working fine when it was first installed in my machine.

I left it on overnight (not cutting or spinning; just powered).

Now it won't start up. It has 220V at the wall, but at the switch in the box on the Bridgeport it's only getting 196V. This is not enough to power up anything on the machine.

I have the diagnostic manual, and have been going through it slowly. I checked all the fuses, and they all seem fine.

Any suggestions? Neither of us are electricians. I was *just* about to cut some parts, too. Very frustrating - any help is HUGELY appreciated!

thanks,

Alex

[Al_The_Man]

There is two principal reasons for a voltage drop, high current, which you would see the effects of, or a high resistance connection or bad termination etc. somewhere.
Are you sure the fuses are OK?
Check the voltage between the wall plug/switch and at every point along the way, e.g. at the top of a fuse or disconnect and again at the bottom.
Al.

[AlexBandar]

Hey Al,

Thanks so much for the quick reply. (I knew joining this group would be great).

I *did* fib a bit when I said the fuses seemed okay. One of them *looks* okay, but I can't pull it out if its housing because there seems to be something stuck to the bottom of it. I moved the Bridgeport into my workshop, and we've had a lot of wood dust recently, and it's right by the fan. It's the fuse for the electrical control box, so I'm not sure it would affect the voltage at the main switch, but I do need to rule that issue out first.

Thanks again.

best,

Alex

Originally Posted by Al_The_Man There is two principal reasons for a voltage drop, high current, which you would see the effects of, or a high resistance connection or bad termination etc. somewhere. Are you sure the fuses are OK? Check the voltage between the wall plug/switch and at every point along the way, e.g. at the top of a fuse or disconnect and again at the bottom. Al.

[Al_The_Man]

If this is a 240v 1phase supply, also check each line to ground along the way, top and bottom of the fuse carrier etc, this should find it if it is open fuse or high resistance.
But you can also be mislead due to the fact that the voltage will back fed from the other live line.
Al.

[AlexBandar]

Thanks again, Al. It's 3-phase, 220V. I have a friend who's helping me with it (the guy I bought it from), but he's around infrequently. I'd do more diagnosis myself, but I only have experience with low voltage electronics (TTL). I'm not even sure how to check the voltage across the fuses of the 3 different lines near the on switch. Think I'll wait till my friend gets back, and hit him with the info you've provided me.

Thanks again!

-Alex

Originally Posted by Al_The_Man If this is a 240v 1phase supply, also check each line to ground along the way, top and bottom of the fuse carrier etc, this should find it if it is open fuse or high resistance. Al.

[Al_The_Man]

I am betting on an open fuse.
Al.