Yaskawa E7B Drive Bypass - Manual (Page 202)

Diagnostic & Troubleshooting 6 - 22
If the Motor Rotates Even When Drive Output is Stopped
If the motor rotates even when the Drive is stopped, the DC injection braking may be insufficient. If the motor continues operating
at low speed, without completely stopping after a stop has been executed, it means that the DC injection braking is not decelerating
the motor enough. Adjust the DC injection braking as follows:
• Increase the parameter b2-04 (DC Injection Braking (initial excitation) Time at Stop) setting.
• Increase the parameter b2-02 (DC Injection Braking Current) setting.
If Zero Volts is Detected When a Motor is Started, or Stalls
Generation of 0V (main circuit voltage) and stalling can occur if a motor is turning when it is started and the DC injection brak-
ing is insufficient.
This can be prevented by slowing motor rotation by DC injection braking before starting. Increase parameter b2-03
(DC injection braking time at start) setting.
If the Accepted Speed Command Does Not Rise to the User Speed Command
Input
The Speed Command is within the jump frequency range.
When the jump frequency function is used, the output frequency cannot be set within the jump frequency range. Check to be
sure that the Jump Frequency (parameters d3-01 to d3-03) and Jump Frequency Width (parameter d3-04) settings are suitable.
The frequency reference upper limit has been reached.
The output frequency upper limit is determined by the following formula:
Freq Ref Upper Limit = Maximum Output Frequency (E1-04)
× Frequency Reference Upper Limit (d2-01) / 100
Check to be sure that the parameter E1-04 and d2-01 settings are suitable.