Toshiba TOSVERT VF-AS3 Instruction Manual page 341

6. 24. 2 Selecting Acc/Dec operation after stall prevention
operation
<F451: Acc/Dec operation after stall operation>
■ Function
When you use lifting gear (crane or hoist) in combination with mechanical brakes, and if the output
frequency is decreasing due to stall prevention operation before mechanical brake release,
accelerate the mechanical brake delay time in the minimum time to prevent load from falling due to
torque reduction after mechanical brake release.
This will also improve the response in inching operation, and thus preventing the load from slipping
down.
■ Parameter setting
Title Parameter name
F451 Acc/Dec operation after
stall operation
■ Selecting a setting value
0: Acc/Dec time
When stall prevention is active, the output frequency gets low.
If stall prevention was active and the output frequency is decreasing before releasing the machine,
even if the mechanical brake is released, the stall prevention remains active during the delay time of
the brake operation . After delay time of the brake operation, the output current value gets low, the
stall prevention operation is deactivated and the output frequency increases.
With this setting, the output frequency reaches the frequency command value after brake operation
delay time + acceleration time. The actual speed of the machinery changes in sync with the output
frequency.
F451 : Acc/Dec operation after stall
0: Acc/Dec time
1: Minimum time
Adjustment range
0: Acc/Dec time
1: Minimum time
6-99
E6582062
STOP 0.0Hz
13:44
Default setting
0
6. [Advanced] How to use parameters
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