The Siemens SENTRON 3VA9977-0UF10 is the Maintenance Mode Box MMB300, a digital input and output module designed as an accessory for the 3VA6 molded-case circuit breaker family. It provides one digital input and two relay outputs for remote signaling and control of the breaker's maintenance mode status. The module mounts in any position and is rated for installation in fixed switchboards inside enclosed rooms, with IP20 protection.
Digital input and supply
The single digital input operates on SELV/PELV per IEC, Class 2 per UL. Signal-1 recognition threshold starts at 15 V and requires 10 mA initial current, scaling to 27 mA full-scale. Signal-0 recognition is below 5 V with a maximum current of 0.2 mA. The module draws a maximum of 0.2 A from the control feed supply, with a rated power loss of 4.8 VA. The supply voltage has a ±20 % relative symmetrical tolerance.
Dimensions and environment
The enclosure measures 36 mm deep, 70 mm wide, and 116 mm high.