Mitsubishi Electric FR-A700 Instruction Manual page 691

Parameter
Fig. 6-256: Parameter 271 and 272
Operation of load torque high speed frequency control setting
When the average current of the current averaging range (above chart A) during operation with
the X19 signal on is less than the "rated inverter current × Pr. 271 setting (%)", the maximum fre-
quency automatically becomes the Pr. 4 "Multi-speed setting (high speed)" setting value.
When the average current of the current averaging range (above chart B) during operation with
the X19 signal on is more than the "rated inverter current × Pr. 272 setting (%)", the maximum
frequency automatically becomes the Pr. 5 "Multi-speed setting (middle speed)" setting value.
The current averaging range can be set between 1/2 frequency of the Pr. 273 setting value and
Pr. 273 set frequency.
NOTES
When the current averaging range includes the constant power range, the output current
may become large in the constant power range
When the average current value in the current averaging range is small, deceleration time
becomes longer as the running frequency increases.
The maximum output frequency is 120Hz. The output frequency is 120Hz even when the
setting is above 120Hz.
The fast-response current limit function is made invalid.
When the average current during acceleration is too small, it may be judged as regeneration
and the maximum frequency becomes the setting of Pr. 5.
Changing the terminal function using any of Pr. 178 to Pr. 189 may affect the other func-
tions. Please make setting after confirming the function of each terminal.
The load torque high speed frequency function is made invalid in the following operation
conditions.
PU operation (Pr. 79) , PU+external operation (Pr. 79) , JOG operation (JOG signal) , PID
control function operation (X14 signal), remote setting function operation (Pr. 59), orientation
control function operation, multi-speed setting (RH, RM, RL signal ), 16 bit digital input
option (FR-A7AX)
b
CAUTION:
When the load is light, the motor may suddenly accelerate to 120Hz maximum, causing
hazard. Securely provide mechanical interlock on the machine side to perform.
FR-A700 EC
Frequency
Pr. 4
(50Hz)
Pr. 5
(60Hz)
Pr. 271
(50%)
Value in parenthesis is initial value.
Pr.272
Average current
(100 %)
Special operation
I001626E
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