Rfc-A Mode; Induction Motor With Position Feedback; Motor Rated Current; Rated Voltage/Frequency - Emerson Unidrive M702 User Manual

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8.1.2

RFC-A mode

Induction motor with Position feedback

Pr 00.046 {05.007} Motor Rated Current
The motor rated current parameter must be set to the maximum continuous current of the motor. (See section 8.2 Maximum motor rated current on
page 127, for information about setting this parameter higher than the maximum Heavy Duty current rating.) The motor rated current is used in the
following:
• Current limits (see section 8.3 Current limits on page 127, for more information).
• Motor thermal overload protection (see section 8.4 Motor thermal protection on page 127, for more information)
• Vector control algorithm
Pr 00.044 {05.009} Rated Voltage
Pr 00.047 {05.006} Rated Frequency
The Rated Voltage (00.044) and the Rated Frequency (00.047) are used
to define the voltage to frequency characteristic applied to the motor (see
Open Loop Control Mode (00.007), later in this table). The motor rated
frequency is also used in conjunction with the motor rated speed to
calculate the rated slip for slip compensation (see motor Rated Speed
(00.045), later in this table).
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).
Unidrive M702 User Guide
Issue Number: 3
Electrical Getting Basic
installation started parameters the motor
Running NV Media Card
Optimization
Operation
Defines the maximum motor continuous current
Defines the voltage applied to the motor at rated frequency
Defines the frequency at which rated voltage is applied
Output
voltage
Pr 00.044
Pr 00.044
Defines the full load rated speed of the motor
Defines the number of motor poles
Defines the angle between the motor voltage and current
Onboard Advanced Technical
Diagnostics
PLC parameters data
Output voltage characteristic
/ 2
Output
Pr 00.047 / 2 Pr 00.047
frequency
UL listing
information
121