The multifunction relay type PMB-2 is designed for protection and control functions of two three-phase outgoing feeders/three-phase loads.
The protection works with external current-voltage converters. It has a wide range of settings, depending on the converters used. It is also possible to use current transformers, because after shorting them with a low resistance it is possible to express the signal in mV/A.
The relay also has an emergency switch circuit (safety switch) and is additionally equipped with leakage protection for a third load.
The relay has LEDs indicating the operating status of the device. Remote access to the device is via the RS-485 interface using the Modbus RTU protocol. As standard the device is fitted with one digital input RST, which is intended as an external input for clearing messages appearing on the display (equivalent to the “RESET” button). The device may be optionally fitted with a larger number of general-purpose inputs whose logical status is indicated on the display and can be read remotely. PMB-2 is also designed to protect outgoing feeders and motors operating in hazardous areas. Output circuits of PMB-2 protection enable operation in hazardous areas and are designed for use in areas classified as class a, b or c of methane explosion hazard and class A or B of coal dust explosion hazard.
Communication with the user is via text messages displayed on the display. Buttons are provided to navigate the device menu.
Functions implemented by the device:
- current protection (overload, short circuit, imbalance, stall of a motor, pump dry run protection),
- leakage blocking/central blocking protection,
- motor temperature protection,
- protection against loss of continuity of the PE protective wire or an excessive increase of its resistance,
- warning signal before switching on equipment,
- outgoing feeder remote and local control,
- remote or local control of actuators,
- contactor control,
- display of operating status and messages,
- transmission of information to other control and monitoring systems.
- communication via MODBUS RTU.
The relay type PMB-2 can be used in the following devices:
- contactor type switches,
- compact stations,
- transformer units,
- transformer/switching stations,
- other switchgear of 3-phase alternating current network with a voltage of up to 1140 V AC 50 Hz installed in the workings of mining plants or other industrial facilities.