Arkel ADrive VVVF - Page 142

TÜRKÇE
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2.9-Rotor Slip (R_slip: 1.0 – 9.0 Hz)
Asynchronous motors have a slip between rotor and electrical rotating field applied to stator.
The value of this slip is entered by this parameter. Too small slip value causes over current and
heating of motor. Too high slip causes unstable motor current and vibration. It is adviced not to
change this parameter’s default value if there is no need. Slip frequency may be calculated by the
formula below:
Fnom
pmStatorNomR
mMotorNomRppmStatorNomR
Fslip *
)(
)( 

)2/(
60*
lesnumberofpo
Fnom
pmStatorNomR 
For example : The slip for a 50Hz , 1440 rpm , 4 poles motor is like below:
1500
2
60*50
pmStatorNomR
Rpm
250*
)1500(
)14401500(


Fslip
Hz
2.10-No Load Motor Current (Inoload: %20 - %80)
Ratio of no load current to nominal current. Too high value causes high motor current.
Consequently motor heat rises and more power consumed. Too low value causes torque loss
which shows itself as a vibration. Values of parameters 2.9 and 2.10 are very critical values for
the motor drive performance. Optimum value is where minimum motor current is obtained
without vibration. For getting to this optimum values the elevator must run a few times and the
motor current should be monitored.
2.11-Rotor Time Constant (T_rotor: 1- 999 ms)
Time constant for motor rotor. Dependence of the inverter to this parameter is reduced, do
not change this parameter if not necessary. This value may be get from the motor manufacturer.
This parameter is needed for vector control.