Excessive Speed Deviation (Pr.285, Pr.853) - Mitsubishi Electric FR-E700EX Instruction Manual

Speed control
(2) Model adaptive speed control (Pr.877 = "2")
The motor's model speed is calculated to feed back the model side speed controller. This model speed is also used

as the actual speed controller command.
The inertia ratio of Pr.880 is used when the model calculates the motor speed or the speed controller calculates the

torque current command value.
The torque current command value of the model side speed controller is added to the output of the actual speed

controller, and the result is used as the iq current control input.
Pr.828 is used for model side speed control (P control), and the first gain in Pr.820 is used for the actual speed
controller.
[Block diagram]
Model adaptive speed control
+
Model speed
Speed command
control gain
-
4.4.5

Excessive speed deviation (Pr.285, Pr.853)

Parameter
Name
number
Excessive speed
285 deviation detection
speed
853 Speed deviation time

When an S-PM geared motor is used, the maximum setting value differs depending on the drive unit capacity. (0.2 to 2.2K: 900 r/min, 3.7K: 600 r/min)
When the deviation between the set frequency and actual speed is large, e.g. too large load torque, this function can cause

the drive unit to provide a speed deviation excessive fault (E.OSD) and come to a trip.
NOTE
 Under position control, speed deviation excess detection is disabled.
84
J
Torque coefficient
(J: [Pr. 880 ])
1
J s
[Pr.828 ]
Model speed
calculation
Initial value
9999
1s
(r/min)
Fault output
(across A-C)
Speed control
+
P gain
- [Pr.820 ]
Speed control
Actual speed controller
integral time
Setting range
9999 Without speed deviation excessive
If the difference (absolute value) between the speed
0 to 360r/min

command value and actual speed during speed
control exceeds the Pr.285 Excessive speed deviation
detection speed for more than the time set in Pr.853
Speed deviation time, speed deviation excessive
0 to 100s
occurs and drive unit fault (E. OSD) appears,
resulting in a trip.
Set speed
Pr.285
Actual rotation speed
Time
Pr.853
OFF ON
Speed deviation
excessive fault activated
(E. OSD)
+
+
Torque
control
+
[Pr.821 ]
Speed
estimator
Description
M