Chapter 12 Description of Parameter Settings
MH300
Pr.02-16–Pr.02-17 Multi-function Output (MO1, 2)
Pr.06-01 Over-voltage stall prevention
Pr.06-03 Over-current stall prevention during acceleration
Pr.06-04 Over-current stall prevention during operation
Pr.06-05 Acceleration / deceleration time selection for stall prevention at constant speed
Traditional over-voltage stall prevention
Used for uncertain load inertia. When it stops under normal load, the over-voltage does not occur
during deceleration and fulfills the deceleration time setting. However, load regenerative inertia
may occasionally increase and does not trip due to over-voltage when decelerating to stop. In this
case, the drive automatically increases the deceleration time until it stops.
Because of the motor load inertia, the motor may exceed the synchronous speed when the drive
decelerates; in this case, the motor becomes generator. If the motor load inertia is larger, or the
setting for drive’s decelerating time is too small, the motor regenerates energy to the drive, and
makes the DC bus voltage increase to the maximum allowable value. Thus, when traditional over-
voltage stall prevention is enabled, the drive does not decelerate further and maintains the output
frequency until the voltage drops below the setting value again.
When the over-voltage stall prevention is enabled, the drive deceleration time is larger than the
setting time.
When there is a problem with the deceleration time, this function is disabled. See below for
solution:
1. Increase the deceleration time properly.
2. Install a brake resistor (refer to Section 7-1 Brake Resistors and Brake Units Selection Chart
for details) to dissipate the heat, that is, the electrical energy regenerating from the motor.
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