Chapter 10. Advanced functions

Example

Rated frequency= 60Hz

Rated motor RPM= 1740rpm

Motor pole number= 4

fs = 60

1740 ⋅ 4

= 2Hz

− ⎜

120

 

 

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

[Load inertia rate]

0Less than 10 times motor inertia

1About 10 times motor inertia

2Greater than 10 times motor inertia

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.

RPM

Synchronous

speed

Slip

compensation

Motor rated

RPM

Load

86

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LG Electronics C Series manual Rpm