Speed Limit - Mitsubishi Electric 800 Series Instruction Manual (Function

6.5

Speed limit

Sensorless Sensorless Sensorless Vector Vector Vector
When operating under torque control, motor overspeeding may occur if the load torque drops to a value less than the torque
command value, etc. Set the speed limit value to prevent overspeeding.
If the actual speed reaches or exceeds the speed limit value, the control method switches from torque control to speed control,
preventing overspeeding.
Pr. Name
807
Speed limit selection
H410
808
Speed limit
H411
809
Reverse-side speed limit
H412
*1 Gr.1 and Gr.2 are the parameter initial value groups. (Refer to
 Control block diagram
Pr. 807 Speed limit selection
Same method
as speed command input
Parameter(Pr. 808, Pr. 809)
 Using the speed command during speed control (Pr.807 = "0" (initial
value))
• Speed limit is set by the same method as speed setting during speed control (speed setting by the operation panel, multi-
speed setting, plug-in option, etc.).
• When the start signal turns ON, the limit level increases from 0 Hz to the set speed by taking the time set in Pr.7
Acceleration time. When the start signal turns OFF, the limit level at the time decreases to the operation start level of
Pr.10 DC injection brake operation frequency, by taking the time set in Pr.8 Deceleration time.
• When the load has reversed the rotation opposite to the torque polarity, the setting of Pr.809 Reverse-side speed limit
is applied for the speed limit.
Rotation speed
Pr.7
Speed setting
value during
speed control
-Pr.809
Reverse-side
speed limit value
OFF ON
Start signal
When the torque command value is positive
*1
Initial value
Setting
range
Gr.1 Gr.2
0
0
1
60 Hz 50 Hz 0 to 400 Hz
0 to 400 Hz
9999
9999
Speed estimated value < speed limit value
Torque command
0
1
+
- Speed estimated value
Real sensorless vector control
The speed setting
value is the speed
limit value.
Range where torque
control is available
Pr.8
Time
Uses the speed command during speed control as the speed limit.
Sets the speed limits for forward and reverse directions individually by
using Pr.808 and Pr.809.
Sets speed limit.
Sets the speed limit when the load has reversed the motor rotation
opposite to the torque polarity.
Pr.808 setting value is effective.
page 54).
+
-
Speed control
speed limit value
Speed estimator
Vector control
Rotation speed
Pr.809
Reverse-side
speed limit value
Speed setting
value during
Pr.7
speed control
OFF ON
Start signal
When the torque command value is negative
Description
Motor
Torque control
Encoder
Range where torque
control is available
Time
Pr.8
The speed setting
value is the speed
limit value.
6. Torque Control
6.5 Speed limit
1
2
3
4
5
6
7
8
9
10
153