Hey Al-the-Man,
We have a simular problem with an 84 Bridgeport R2E3 with the spindle not starting (dropping out after 1 second) We can manually press the contactor inside the main electrical cabinet and make the spindle rotate in forward and reverse. We have a DESCO 5hp, 3 phase, CNC converter. Input voltage with no load is 240volts. When we manually engage the contactor for spindle rotation it makes a growling noise until spindle gets up to speed. Here is the data that we collected with the help from an CNC tech who was helping us. Leg A to Leg B drops from 240V to 160V while spindle is speeding or spooling up. Once the spindle is up to speed the voltage comes back to 240V. Leg B to C drops from 240V to 126V, while spindle is spooling up. Frequency has been checked and is perfect at 60 hertz. Checked to see if 3 phase rotary motor RPM drops under load and it doen not. Also checked voltage at shop circuit breaker box, and it only drops 10V when spindle is spooling up. Our conclusion is that the spindle is not coming up to speed due to low voltage from the phase converter. Phase converter seems to be large enough, but apperas not to be doing the job. When this happens the drives on the machine are disabled and the machine propmts you to home the drives again or sometimes it just plain locks up. Any help on what to look for or check out would be greatly appreciated.
THANKS!!!!!!  |