This time delay unit is an auxiliary device that can be combined with an undervoltage release (MN). It must be connected to an undervoltage release MN of 48 V DC. It prevents false trips due to temporary voltage dips lasting from 200 ms to 3 s. The power supply is 48-60 VDC or 48-60 VAC 50/60 Hz. This time delay unit has 4 adjustable levels (0.5 s - 1 s - 1.5 s - 3 s). It is an external accessory that can be installed in the switchgear.