SSD 605C Product Manual - page 138

6-72  

Programming Your Application

605C Frequency Inverter

UNDERLAP COMP

The underlap compensation function block

ensures sinusoidal motor current at low

motor speeds.

This significantly reduces `cogging’

(rough/pulsating  motor rotation) at low speeds.

Underlap compensation is especially desirable

in lift or hoist applications.

Functional Description

Underlap is the bridge switching delay required for correct operation of the Inverter power

electronic output stage. The delay causes errors in the Inverter output voltage leading to non-

sinusoidal motor currents at low motor speeds. The result is motor cogging, and a loss of motor

torque at low speeds.

Underlap compensation removes underlap errors, and provides consistent motor operation

regardless of motor speed.

MMI Menu Map

1 SETUP PARAMETERS

2 FUNCTION BLOCKS

3 MOTOR CONTROL

4 UNDERLAP COMP

ULC ENABLE

UNDERLAP COMP

TRUE – [600]

ENABLE

–

Parameter Descriptions

ENABLE

Range: FALSE / TRUE

Enables underlap compensation when set to TRUE.