Mitsubishi Electronics FR-D720-008 ユーザーズマニュアル
78
4.3.3
Slip compensation (Pr. 245 to Pr. 247)
Slip compensation is validated when the motor rated slip calculated by the following formula is set in Pr. 245. Slip
compensation is not made when Pr. 245 = "0" or "9999".
compensation is not made when Pr. 245 = "0" or "9999".
Inverter output current may be used to assume motor slip to keep the motor speed constant.
Parameter
Number
Name
Initial Value
Setting Range
Description
245
Rated slip
9999
0.01 to 50%
Rated motor slip
0, 9999
No slip compensation
246
Slip compensation time
constant
0.5s
0.01 to 10s
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.OV ) is more
liable to occur.
value is made smaller, response will be faster.
However, as load inertia is greater, a
regenerative overvoltage fault (E.OV ) 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)
power range. (frequency range above the
frequency set in Pr. 3)
9999
Slip compensation is made in the constant power
range.
range.
The above parameters can be set when Pr. 160 Extended function display selection = "0". (Refer to page 162)
Rated slip =
Synchronous speed at base frequency - rated speed
× 100[%]
Synchronous speed at base frequency
REMARKS
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.
frequency value a little higher than the set frequency.
Parameters referred to
Pr. 1 Maximum frequency
Pr. 3 Base frequency