Slip Compensation - LG SV-iC5 Series Instruction Manual

H32 : Enter the slip frequency based on the following formula and motor nameplate.
×

rpm
= −

f f
s r

120
f
Where, = Rated slip frequency
s
f
r = Rated frequency
rpm
= Motor nameplate RPM
P
= Number of Motor poles
Example
Rated frequency= 60Hz
Rated motor RPM= 1740rpm
Motor pole number= 4
H32- [Rated slip frequency] is 2Hz. Set H32- [Rated slip frequency] to 2.
H33 : Enter the motor nameplate rated current
H34 : Enter the measured current when the motor is running at rated frequency after the load is
removed. Enter 50% of the rated motor current when it is difficult to measure the motor no load current.
H36 : Enter motor efficiency on the nameplate.
H37 : Select load inertia based on motor inertia as shown below.
H37
As the loads are heavier, the speed gap between rated RPM and synchronous speed is widening
(see the figure below). This function compensates for this inherent slip. Set the Torque boost value
within 2%. Setting it too high may cause motor over-energizing and lead to error in calculating slip
speed.

P



1740
= −

f 60
s

120
[Load inertia rate]
RPM
Synchronous
speed
Motor rated
RPM
Load
10-7
10. Advanced functions
×

4
=

2 Hz

0 Less than 10 times motor inertia
1 About 10 times motor inertia
Greater than 10 times motor
2
inertia
Slip
compensation
SV-iC5