This time delay unit is an auxiliary that can be combined with an undervoltage release (MN). It must be associated with a 125VDC MN undervoltage release. It eliminates the risk of nuisance tripping due to transient voltage dips lasting from 200ms to 3s. Its power supply is 100-130VDC or 100-130VAC 50/60Hz. This time delay unit has 4 adjustable steps (0.5s - 1s - 1.5s - 3s). It is an external accessory and can be mounted in the switchboard.