Speed Limit - Mitsubishi Electric 800 Series Instruction Manual

6.4

Speed limit

Sensorless Sensorless Sensorless
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
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.
Speed
Forward rotation
Pr.7
Speed setting
value during
speed control
Reverse rotation
STF(STR) ON
NOTE
• The second acceleration/deceleration time can be set.
• When speed limit command exceeds Pr.1 Maximum frequency setting, the speed limit value becomes Pr.1 setting. When
speed limit command falls below Pr.2 Minimum frequency setting, the speed limit value becomes Pr.2 setting. Also, the
speed limit command is smaller than Pr. 13 Starting frequency, the speed limit value becomes 0 Hz.
• To use analog inputs to perform speed limit, calibrate analog input terminals 2 and 4. (Refer to
• To use analog inputs to perform speed limit, turn OFF the external signals (RH, RM, RL). If any of the external signals (RH,
RM, RL) is ON, speed limit by multi-speed are enabled.
122
6. Torque Control
6.4 Speed limit
*1
Initial value
Gr.1 Gr.2
0
60 Hz 50 Hz 0 to 400 Hz
9999
Speed estimated value < speed limit value
Torque command
Pr. 807 Speed limit selection
0
1
+
- Speed estimated value
The speed setting
value is the speed
limit value.
Pr.8
Time
Torque controllable
range
OFF
Setting
range
0 Uses the speed command during speed control as the speed limit.
Sets the speed limits for forward and reverse directions individually by
1
using Pr.808 and Pr.809.
Sets speed limit.
Sets the speed limit when the load has reversed the motor rotation
0 to 400 Hz
opposite to the torque polarity.
9999 Pr.808 setting value is effective.
page 50).
Speed control
speed limit value
Real sensorless vector control
Description
+
Torque control
-
Speed estimator
page 282.)
Motor