Avoiding Motor Overrunning - Mitsubishi Electric FR-A820-00046 Instruction Manual

Speed control under Real sensorless vector control, vector control, PM sensorless vector control
5.3.9

Avoiding motor overrunning

Motor overrunning due to excessive load torque or an error in the setting for the number of encoder
pulses can be avoided.
Pr.
285
H416
853
H417
873
H415
690
H881
This is the overspeed detection frequency under encoder feedback control. (Refer to page 5-692.)
These parameters are available when a vector control compatible option is installed.
The setting is available when the FR-A8AP or the FR-A8TP is installed.
Speed deviation excess detection (Pr. 285, Pr. 853)
● A trip 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.
● When the difference (absolute value) between the speed command value and actual rotation
speed in speed control under vector control is equal to higher than the setting value in Pr. 285
"Speed deviation excess detection frequency" for a continuous time equal to or longer than the
setting value in Pr. 853 "Speed deviation time", Speed deviation excess detection (E.OSD) activates
to shut off the inverter output.
Fault output
(ALM)
5 - 118
Initial
Name
value
Speed deviation
excess detection
9999
frequency
Speed deviation time 1s
Speed limit 20 Hz
Deceleration check
1 s
time
Set frequency
Pr. 285
Actual speed
Pr. 853
OFF ON
Speed deviation
excessive fault
activated (E. OSD)
Vector Vector Vector
Setting
Description
range
Set the speed deviation excess detection frequency
(difference between the actual rotation speed and
0 to 30 Hz
speed command value) at which the protective function
(E.OSD) activates.
9999 No speed deviation excess
Set the time from when the speed deviation excess
0 to 100 s state 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
Fig. 5-33:
Speed deviation excess detection
Time
Parameters
I001518E