Issue with resolver in motor.

Dear all,

We have S120 drive for chute rotation application with servo motor. Earlier it was running with resolver. Now we have bypassed resolver as there is issue with resolver in motor. Now we are facing over speed fault intermittently. Maximum speed is 2000rpm, p2162(hysteresis) is 40rpm. Speed setpoint is 1174rpm. In encoderless speed is calculated based on current. Should i repeated motor ID run??

Surendhar M

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Split from Sinamcs S120 Overspeed Limit.

Dear Sir,

We have planned to change the motor in shutdown. Fault is not coming regularly. Came 3 times in 2 days. But wanted to know why can't we run it in encoderless mode. Will there be a speed difference of 826 rpm. As setpoint is 1174 and overspeed limit is 2000rpm. 

Regards

Surendhar M

If the original equipment required a resolver to operate within proper specifications for speed, running without a resolver is like duct taping the sole of the shoe to the top of the shoe rather than getting a new shoe.

Try running at full speed and you will probably blow out the shoe again.  Try jogging and it might go great for a while, but eventually the duct tape wears out and the shoe blows out again.  Try walking, and you can go for a really long time, but it will take a long time to get there.

Same kind of thing applies to running other than as designed.

If you were using a G120 with encoder/resolver feedback, you can replace with an S120 drive in encoderless mode and get similar control.  I think a resolver is less expensive.

Surendhar_M

Dear Sir,

We have planned to change the motor in shutdown. Fault is not coming regularly. Came 3 times in 2 days. But wanted to know why can't we run it in encoderless mode. Will there be a speed difference of 826 rpm. As setpoint is 1174 and overspeed limit is 2000rpm. 

Regards

Surendhar M

Dear Sir,

We have S120 drive. By design it was there that encoder fault response is switch to encoderless operation via p491.

I increased the rampup time. Now there are no current spikes and now fault is not coming..

Thanks...