[gcpmachine101]

Hello everyone! First time to field a question on here. Although I've used this site before to fix our Quik Turn 20. I don't even want to get into how grateful we were for that! This time one of our mills are down and I feel confident that I can get the help I need from some of you guys. So a huge thank you in advance to all of you for your input.Now here's the problem
First, the machine in question is an otherwise very reliable
1984 v5 Mazak Micro 3-axis machining center w/ FANUC 6mb controller. I had a spindle motor alarm pop-up right when I tried to activate the spindle and after an investigation into the problem we realized that 2 out of 3 of 1.3 amp alarm fuses were blown on our VCU. We quickly replaced those 2 (left and right ones) and upon firing the machine back up they blew out again. Also one of the 5 (third from bottom) vertical LEDs on the left lights up. We've went over our manuals and can't find anything useful. If someone has an outright solution that would be awesome! I would still be just as thankful for some relevant insight or to just be steered in the right direction. I'm inexperienced using internet forums is it possible for me to move this to the correct forum? Please HELP!

[Al_The_Man]

Usually the alarm fuses are in parallel to the main 3 phase fuses, they are there for alarm only, If the one of the main fuses blow, it leaves the low current alarm fuse to take the brunt, which blow immediately, setting the alarm.
Al.

[cncdiag]

The 1.3 amp fuses are there to tell you the main fuses are blown.
Replace main fuses and indicator fuses

[gcpmachine101]

I have change one of the main fuses ( yes it was broke) in our VCU and the problem still exists any other possibilities? Also, thank you Al and CNCdiag for your help so far

[Al_The_Man]

If by 'The problem still exists' and it is blowing main fuses, try disconnecting the motor armature, and switch on, if main fuse still blows, the drive is probably shorted, if the fuse stays in until you reconnect the motor there is most likely a short in the motor, or wiring.
Al.

[gcpmachine101]

Thanks for the additional info Al. I will follow your instructions and update you soon.

[Leelund]

If still blowing main fuses, unwire the motor from the drive and megger the motor to ground. If not shorted,the motor leads and motor are good. Drive is bad. If shorted, unwire the motor at the motor junction box and independently check the motor then the motor leads to find the culprit. WARNING! Do not meggar check with the motor leads attached to the controller! If no megohmeter is available use an ohmmeter.
Lee