Under Frequency

Default value

• Dropout: 95% of the rated frequency.

• Pickup: 97% of the rated frequency.

Range

• Range for falling voltage (dropout) is 80%–95% of rated voltage.

• Range for return voltage (pickup) is 85%–100% of rated voltage.

Adjustable

The adjustable step for under frequency threshold is 0.5%.

Differential

• The default differential between dropout and pickup is equal to 0.5% of rated frequency.

On LCD display

• If minimum differential rule is broken during dropout setting, the pickup value will be modified (pickup = dropout – 0.5% ) to keep the rule.

On Modbus

Dropout value is always accepted, if the pickup value doesn't comply the minimum differential, the pickup value will be modified to value (pickup = dropout – 0.5%).

Sequence of events

• When a sensor detects a frequency below the set drop-out frequency for a period longer than the time delay, it deems the voltage is out of range.

• When the sensor detects a frequency at or above the pick-up point, it deems the frequency as acceptable.