Toshiba H9 User Manual

H9 ASD Installation and Operation Manual

249

Overvoltage

DC bus voltage exceeds 
specifications.

• ASD attempting to start into a spinning motor after a 

momentary power loss.

• Incoming commercial power is above the specified 

range.

• Decel time is too short.

• Voltage spikes at the 3-phase input; install inductive 

filter.

• DBR required.

• DBR resistance value is too high.

• DBR function is turned off.

• Overvoltage Stall feature is turned off.

• System is regenerating.

• Load instability.

• Disable the Ridethrough function (

Overtorque

Torque requirement is in excess 
of the setting of 

 or 

for a time longer than the setting 
of 

• ASD is not correctly matched to the application.

•

 setting is too low.

• Obstructed load.

Control 
Undervoltage

Undervoltage condition at the 5, 
15, or the 24 VDC supply.

• Defective Control board.

• Excessive load on power supply.

• Low input voltage.

Reference Point

Two speed-reference frequency 
setpoint values are too close to 
each other.

• Two speed reference frequency setpoints are too close to 

each other (increase the difference).

Undercurrent

With the Low-current Trip 
(

) parameter enabled, the 

output current of the ASD is 
below the level defined at 

and remains there for a time 
longer than the setting of 

.

this function sets the low-current trip threshold

* Reset ignored if active.