Mitsubishi Electric FR-A700 Series, Technical Manual

Page: 347 / 550

381
PARAMETER
2
P
ARAM
ETE
R
2.17.5 Overspeed detection [Pr. 374]
(A700)
2.17.6 Encoder signal loss detection [Pr. 376]
(A700)
When the encoder signal is lost during encoder feedback
control, orientation control, or vector control, signal loss
detection (E.ECT) is activated to trip the inverter.
2.17.7 Earth (ground) fault detection at start [Pr. 249]
You can choose whether to make earth (ground) fault detection at start valid or invalid.
When [ Pr.249 =1], earth (ground) fault detection is
performed at start. Earth (ground) fault detection is
performed only after start signal is input to the inverter.
Protective function does not operate for the ground (earth)
fault, which occurs while inverter is running.
Because the detection is performed at a start, output
delays for about 20ms at every start.
If earth (ground) fault is detected when [ Pr.249 =1], output
side earth (ground) fault overcurrent (E.GF) is output, and
the inverter output is shutoff. (
Refer to page 99 )
If motor capacity is smaller than the inverter capacity in
5.5K or more, ground (earth) fault protection may not
operate.
A700
[Pr. ] Name
Initial
Value Setting
Range
Description
374 Overspeed detection level 140Hz 0 to 400Hz
When the motor speed reaches or exceeds the speed set in [
Pr. 374
]
during encoder feedback control, Real sensorless vector control, or
vector control, over speed (E.OS) occurs and trips the inverter.
ALM
Motor speed *
Time
E.OS
Coast to stop
ON
[
Pr. 374
]
* The output frequency and [ Pr. 374 ] are compared during Real sensorless
vector control.
A700
[Pr. ] Name
Initial
Value Setting
Range
Description
376
Encoder signal
loss detection
enable/disable
selection
0
0
Signal loss
detection is invalid
1
Signal loss
detection is valid
E700 D700
[Pr.] Name Initial Value Setting Range Description
249 Earth (ground) fault detection at start 0
0 Without earth (ground) fault detection
1 With earth (ground) fault detection