If torque is required in a low-speed range (less than 1/10 of the rated motor frequency), set Pr.791 Acceleration time in
low-speed range and Pr.792 Deceleration time in low-speed range settings higher than the Pr.7 Acceleration time and Pr.8
Deceleration time settings so that the mild acceleration/deceleration is performed in the low-speed range. (For an
operation with second acceleration/deceleration times, set the acceleration/deceleration times longer than the second
acceleration/deceleration times.)
Acceleration time
in low-speed range
Slope set by Pr. 791
REMARKS
Set Pr.791 higher than Pr.7, and Pr.792 higher than Pr.8. If set as Pr.791 < Pr.7, the operation is performed as Pr.791 = Pr.7. If
set as Pr.792 < Pr.8, the operation is performed as Pr.792 = Pr.8.
Refer to page 6 for the rated motor frequency of MM-CF.
1.8
DC injection brake of the PM sensorless vector control
DC injection brake under PM sensorless vector control is performed as below.
<High frequency superposition control (Pr.788 = "9999 (initial value)")>
When Pr.11
Commanded speed
DC injection brake applied
when:
The commanded speed = 0Hz
The calculated speed
<Current synchronization operation Pr.788 = "0">
When Pr.11
DC injection brake applied when
the commanded and calculated
speeds are 0Hz
REMARKS
The X13 signal is disabled during PM sensorless vector control.
Acceleration time
Slope set by Pr.7
"0"
Calculated speed
Pr.10
Time
Pr.10
Time
Pr.11
"0"
Time
Time
Pr.11
Low-speed range
(rated motor frequency/10)
Time
Deceleration time
Slope set by Pr.8
When Pr.11 = "0"
Commanded speed
Motor coasting when:
The commanded speed
The calculated speed
When Pr.11 = "0"
Commanded
speed
Motor coasting when:
The commanded speed
The calculated speed
15/24
Deceleration time
in low-speed range
Slope set by Pr.792
P M
P M
P M
Calculated speed
Pr.10
Time
Pr.10
Pr.10
Calculated speed
Pr.10
Time
Pr.10
Pr.10
BCN-C22005-634