Mitsubishi Electric FR-A700 Series, Technical Manual

Page: 357 / 550

391
PARAMETER
2
P
ARAM
ETE
R
2.19 Frequency compensation function
2.19.1 Slip compensation [Pr. 245 to 247]
(common)
Motor speed can be kept constant by estimating motor slip from output current under V/F control, Simple magnetic flux vector
control (only in
), and General-purpose magnetic flux vector control (only in .)
Slip compensation is valid when the motor rated slip
calculated by the following expression is set in [
Pr. 245 ] .
Slip compensation is not made when [ Pr. 245 = 0, 9999 ].
When performing slip compensation, the output frequency
may become greater than the set frequency. Set the [
Pr. 1
Maximum frequency ] value a little higher than the set
frequency.
[ Pr.245 to 247 ] settings are invalid under Advanced
magnetic flux vector control in , Real
sensorless vector control in , and vector control
since slip compensation is performed under these controls.
When encoder feedback control is performed by
,
[
Pr. 245 to Pr. 247
] settings are invalid.
[Pr.] Name Initial Value Setting Range Description
245 Rated slip 9999
0.01 to 50% Used to set the rated motor slip.
0, 9999 No slip compensation
246 Slip compensation time constant 0.5s 0.01 to 10s
Used to set the slip compensation response
time. When the value is made smaller, response
will be faster. However, as load inertia is greater,
a regenerative overvoltage fault (E.OV1 to 3) is
more liable to occur.
247
Constant-power range slip
compensation selection
9999
0
Slip compensation is not made in the constant
power range (frequency range above the
frequency set in ([
Pr. 3 ]).
9999
Slip compensation is made in the constant power
range.
common
F700 E700 D700
Rated slip =
(Synchronous speed at base
frequency)
-
Rated
speed
×
100 [%]
Synchronous speed at base frequency
A700 E700
A700
A700