Feedback loss on a Reliance DC drive

[bfrankin]

Hello,
During a normal workday we began experiencing a "feedback loss" alarm on a Reliance Flex-Pak drive. Can anyone point me in the right direction?

The DC motor is 50HP and we are using a tachometer for the feedback method. The tach was replaced in the last 6 months so I don't think it is the tach gen. 

Could there be a bad board in the drive?

Thanks in advance for any help.

[admino]

Tach generators can be tested easily. Even though the tach gen was replace in the last 6 months that doesn't necessarily mean it's good. I recommend you remove it from the motor and bench test.

Chuck it up in a cordless drill and use some alligator clips to secure a voltmeter on DC volts. See what kind of output you get.