The motor rated voltage is used by the field controller to limit the voltage applied to the motor. Normally this is set to the nameplate value. To allow

current control to be maintained, it is necessary for the drive to leave some 'headroom' between the motor terminal voltage and the maximum

available drive output voltage. For good transient performance at high speed, the motor rated voltage should be set below 95 % of the minimum

supply voltage to the drive.

The motor rated voltage and motor rated frequency are also used during the rotating autotune test (see Autotune Pr 00.040 later in this table) and in

the calculations required for automatic optimization of the motor rated speed (see Motor rated speed optimization Pr 05.016, later in this table).

Therefore, it is important that the correct value for motor rated voltage is used.

Pr 00.045 {05.008} Rated Speed

Pr 00.042 {05.011} Number Of Motor Poles

The motor rated speed and motor rated frequency are used to determine the full load slip of the motor which is used by the vector control algorithm.

Incorrect setting of this parameter has the following effects:

•

Reduced efficiency of motor operation

•

Reduction of maximum torque available from the motor

•

Reduced transient performance

•

Inaccurate control of absolute torque in torque control modes

The nameplate value is normally the value for a hot motor; however, some adjustment may be required when the drive is commissioned if the

nameplate value is inaccurate. Either a fixed value can be entered in this parameter or an optimization system may be used to automatically adjust

this parameter (see Motor Parameter Adaptive Control (05.016), later in this table).

When Pr 00.042 is set to 'Automatic', the number of motor poles is automatically calculated from the motor Rated Frequency (00.047), and the

motor Rated Speed (00.045).

Number of poles = 120 x (Motor Rated Frequency (00.047 / Motor Rated Speed (00.045) rounded to the nearest even number.

Pr 00.043 {5.10} Rated Power Factor

The power factor is the true power factor of the motor, i.e. the angle between the motor voltage and current. If the Stator Inductance (05.025) is set

to zero then the power factor is used in conjunction with the motor Rated Current (00.046) and other motor parameters to calculate the rated active

and magnetising currents of the motor, which are used in the vector control algorithm. If the stator inductance has a non-zero value this parameter

is not used by the drive, but is continuously written with a calculated value of power factor. The stator inductance can be measured by the drive by

performing a rotating autotune (see Autotune (Pr 00.040), later in this table).

154

Electrical

Getting

Basic

installation

started

parameters

the motor