abb Vmax MU release

Undervoltage release (-MU)

The undervoltage release opens the circuit-breaker when there is notable lowering or lack of
its power supply. It can be used for remote release (by means of normally closed type
pushbuttons), to control the voltage in the auxiliary circuits or for mechanical lock on closing
allowed only with release energized.
The circuit-breaker can only close with the release supplied (the closure lock is made mechanically).
The release can operate both in direct and alternating current.
The undervoltage release is available in the following versions:
4A Undervoltage release with power supply branched on the supply side.
4B Undervoltage release with electronic time delay device (0.5 – 1 – 1.5 – 2 -3 s) (power supply
branched on the supply side). This device is delivered set at 0.5 s (for adjustment, please see
the Electric Circuit Diagram chapter).
Characteristics
Un: 24 – 30 – 48 – 60 – 110 – 125 – 220 – 250 V–
Un: 24 – 48 – 60 – 110 – 120 – 127 – 220…240 V ~ 50 Hz
Un: 110 – 120…127 – 220…240 V ~ 60 Hz
Operating limits: – circuit-breaker opening: 35-65% Un
– circuit-breaker closing: 85-110% Un
Power on inrush (Ps): DC = 200 W; AC = 200 VA
Inrush duration: about 100 ms
Continuous power (Pc): DC = 5 W; AC = 5 VA
Opening time: 30 ms
Insulation voltage: 2000 V 50 Hz (for 1 min)