No-Load Current Of Motor; Auto Slip Compensation Gain - Delta Electronics AC Drive VFD-F Series User Manual

This parameter is used with slip compensation Pr.7-04 to Pr.7-05 and electronic thermal
relay Pr.6-06 to Pr.6-07. An incorrect setting will cause these functions to not work
incorrectly and may damage the motor and drive.
The full-load current of the motor must be equal to or less than (but not less than 50%) the
rated current of the AC drive.
07 - 03

No-load Current of Motor

Settings
This parameter sets the no-load current of the motor.
Pr.7-03 = (no load current / drive rated current)
Example: If the rated current of the AC drive is 150A and no-load current of the motor is 40A,
then Pr.7-03 should be set to 27%.
This parameter is used with slip compensation Pr.7-04 and Pr.7-05. An incorrect setting will
cause the function to work incorrectly and may damage the motor and drive.
If the no-load current of the motor is unavailable, it may be found by running the motor with
no load and reading the current on the keypad display.
07 - 04

Auto Slip Compensation Gain

Settings
This parameter is set to auto slip compensation gain.
Rotor speed of the motor (output frequency of AC drive) can't synchronize due to induction
motor characteristic. The difference between synchronization speed and rotor speed is
called slip frequency. Slip frequency is in direct proportion with output torque and output
current. Therefore, slip compensation could make rotor speed and master frequency
command the same according output current (lo).
The equation of slip compensation is (07-05) X (07-04) X (Io-(07-03)) / ((07-02)-(07-03)). If
rated current of AC drive is 150A, full-load current of the motor is 120A, no-load current is
40A, rated slip frequency is 5Hz and output current of AC drive is 100A. At this time, slip
compensation is (07-04) X 5 X (100-40) / (120-40) = 3.75 X (07-04). If 07-04 is set to 1.0
and the compensation is 3.75. If master frequency command is set to 50Hz and output
frequency is 53.75.
Output frequency after compensation is limited by 01-07 upper bound frequency. When
using slip compensation, 01-07 should be set to the suitable value.
When PID feedback control, slip compensation function will be disabled.
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1~99%
0.0~3.0
5-37
VFD-F Series
Factory Setting: 30%
Unit: 1
Factory Setting: 0.0
Unit: 0.1
5