| ??? 12/13/05 06:19 Read: times |
#105117 - Vibration or resonance..? Responding to: ???'s previous message |
Prahlad J. Purohit said:
When the motor is stopped ie. pulse sending is stopped. The rotor is forced comes to rest from a speed of 60RPM immediately. Thus the Kinetic Energy of rotor which rapidly becomes 0 gets converted to vibrational energy and cause mechanical vibrations in motor. Also while stopping a returning from a premature step leads to rotor vibrations. Dear Prahlad, At 60RPM operation if stepper is suddenly stoped, then I don't think it will cause vibrations. The drive will hold the shaft and the load on the shaft will balence the operation resulting no vibration. The cause for it may be different. May be resonance frequencies. It must be defined in the datasheet of that stepper motor. But then are you suddenly starting the feed of 60RPM pulses to the drive? I think no. But if you are doing so then there may arise a problem of resonance frequency locking of stepper motor.(Which creates resonance in the rotor shaft) though 60RPM is the ideal speed operation for stepper, but you can not suddenly start it by 60RPM. So generally the Motor and Drive people suggest the ramp up and ramp down technique to start and stop stepper motors so as to avoid these problematic frequencies. Or atleast cross them as early as possible. How much serious is the noise? Is it continuously humming? Or the PWM is very high? Have you observed the current waveform on CRO? Please upload the waveform. Sarang |
