Schneider Electric 58 TRX Adjustment Parameters

Altivar® 58 TRX AC Drives

Adjustment Parameters

Skip Frequency

This parameter, also referred to as jump frequency, allows suppression of a critical speed which causes

mechanical resonance phenomena. Prolonged operation of the motor withi n a freq uen cy ba nd of 5 H z

is prohibited. The frequency band is adjustable ove r the s peed range . A rep resenta tion o f this is shown

to the left. There are three skip frequency settings.

This function is useful for applications involving ligh t-weight ma chines , such as bulk product con v ey or s,

with unbalanced motors. It is also useful for applications involving fans and centrifugal pumps.

Low Speed Run Time Limit

This function, also referred to as a sleep function, is used to stop the motor after running at low speed

for a programmed amount of time, with the run command present and z ero speed ref erence . The length

of run time at low speed is adjustable from 0.1 to 999.9 seconds. The factory setting is 0 s, which

disables this function. The motor will re-start if the frequency reference becomes greater than the low

speed or the run command is cycled.

This function can be used for automatic starting and stopping of pressure-regulated pumps.

IR Compensation

This parameter is used to adjust low-speed torque for optimal performance. Adjust this parameter to

compensate for the resistive voltage drop of the motor stator windings and the conductors connecting

the motor and drive controller.

The factory setting is 100%, with a range of 0 to 150%. (If using special motors such as synchronous

permanent magnet motors, synchronous wound field motors, or synchronous reluctance motors, the

adjustment range can be expanded and is 0 to 800%.)

This parameter is typically used to boost torque performance during low speed operation. If an auto-

tune is performed, adjustment of this parameter is usually not required.

Slip Compensation

This parameter is used to adjust the slip compensation to imp ro v e spe ed regulat ion.The f act ory settin g

is 100%, with a range of 0 to 150%.

Induction motors develop torque based on the slip, which is the difference between the speed of the

rotating magnetic field in the stator and the speed of the rotor. As the load increases, the slip increases

to produce the necessary torque. In applications where the change in s peed due to slip is undesirable,

the slip compensation should be increased. When this parameter is increased, the drive controller will

automatically increase the output frequency. The amount of increase is proportional to the increase of

the load, allowing one setting for the entire speed range.

Gain

This parameter allows adjustment of the drive controller’ s response time to sudden changes in the mo tor

load. The factory setting is 20%, with a range of 0 to 100%.

Decreasing the gain parameter slows the response time of the drive. Increasing the gain parameter

makes the drive respond more quickly. This parameter should be increased when it is not desirable for

motor speed to change as the motor load changes, such as in application s that ha v e fa st cycle ti mes or

high torque requirements.

Stability

This parameter allows adjustment of speed overshoot of the drive controller to sudden changes in the

motor load. The factory setting is 20%, with a range of 0 to 100%.

Increasing the stability setting dampens the overshoo t. This par ameter shoul d be adjuste d with the gain

setting to tune the drive response to meet desired perf ormance on applicatio ns that hav e fast c ycle times

or high torque requirements.

(

)

Fre

Skip Frequency

Diagram