Prevent The Motor From Overrunning (Pr. 285, Pr. 853, Pr. 873) - Mitsubishi Electric FR-A700 Instruction Manual

Parameter
6.3.6 Prevent the motor from overrunning
(Pr. 285, Pr. 853, Pr. 873)
This function prevents the motor from overrunning when the load torque is too large and incor-
rect number of encoder is set.
Pr.
Name
No.
Excessive speed
285
deviation detection
frequency
Speed deviation
853
time
873
Speed limit
Acts as Overspeed detection frequency under encoder feed back operation.
This parameter can be set when the FR-A7AP (option) is mounted.
Speed deviation excessive (Pr. 285, Pr. 853)
When the deviation between the set frequency and actual speed is large, e.g. too large load
torque, this function can cause the inverter to provide a speed deviation excessive alarm
(E.OSD) and come to an alarm stop.
Alarm output
(across A-C)
FR-A700 EC
Speed control by real sensorless vector control, vector control
Initial
Setting Range Description
Value
9999 Without speed deviation excessive
9999
If the difference (absolute value)
0–30Hz
between the speed command value
and actual speed during speed con-
trol under vector control exceeds
the Pr. 285 "Excessive speed devia-
tion detection frequency" for more
1.0s 0–100s
than the time set in Pr. 853 "Speed
deviation time", speed deviation
excessive occurs and inverter error
(E.OSD) appears, resulting in a
stop.
Frequency is limited at the set fre-
20Hz 0–120Hz
quency + Pr. 873.
Pr. 285
Actual
speed
Pr. 853
OFF ON
Speed deviation
excessive error activated
(E. OSD)
Vector Vector Vector Sensorless Sensorless Sensorless Magnetic flux Magnetic flux Magnetic flux
Fig. 6-22:
Speed deviation excessive detection
Set
frequency
Time
V/F V/F V/F
Parameters referred to
285 Overspeed detec-
tion frequency
Refer to
Section
6.13.5
I001518E
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