Avoiding Motor Overrunning - Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual

• Set the time for continuing the output torque simply by using the command value for the torque bias in Pr.845 Torque bias
operation time.
Torque bias filter
primary delay time
Pre-excitation LX
*1 When pre-excitation is not performed, the torque bias functions at the same time as the start signal.
NOTE
• When torque bias is enabled and Pr.868 = "6", terminal 1 operates as a torque command instead of a frequency setting
auxiliary. When override compensation is selected using Pr.73 Analog input selection and terminal 1 is the main speed, no
main speed (main speed = 0 Hz) is set.
• The torque bias is valid for the first motor. When applying the second motor (RT signal is ON), the torque bias function is not
performed.
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) may affect the other functions.
Set parameters after confirming the function of each terminal.
Parameters referred to
Pr.73 Analog input selectionpage 473
Pr.178 to Pr.189 (Input terminal function
C16 to C19 (Pr.919, Pr.920) (torque setting voltage (current)
5.3.9

Avoiding motor overrunning

Vector Vector Vector
Motor overrunning due to excessive load torque or an error in the setting of the number of encoder pulses can be avoided.
Pr. Name
Speed deviation excess detection
285
*1
H416
frequency
*2
853
Speed deviation time
H417
*2
873
Speed limit
H415
690
Deceleration check time
H881
*1 This is the overspeed detection frequency under encoder feedback control. (Refer to
*2 The setting is available when a Vector control compatible option is installed.
 Speed deviation excess detection (Pr.285, Pr.853)
• A shutoff can be set for when the deviation between the set frequency and actual rotation speed is large, such as when
the load torque is excessive.
Speed
Torque bias
Pr. 844
constant
Output torque
Time when torque is
Pr. 845
generated by
torque bias setting
∗1
Start signal
selection)page 496
bias/gain)page 487
Initial value
9999
1.0 s
20 Hz
1.0 s
5.3 Speed control under Real sensorless vector control, vector control, PM sensorless vector control
Setting
range
Set the speed deviation excess detection frequency
(difference between the actual rotation speed and speed
0 to 30 Hz
command value) at which the protective function (E.OSD)
activates.
9999 No speed deviation excess
Set the time from when the speed deviation excess state
0 to 100 s is entered to when the protective function (E.OSD)
activates.
Set the frequency limit with the set frequency + Pr.873
0 to 400 Hz
value.
Set the time required to shut off output due to
0 to 3600 s
deceleration check after the start signal is OFF.
9999 No deceleration check
page 700.)
Description
5. PARAMETERS
1
2
3
4
5
6
7
8
9
10
259