UBZ-302 protects the electric motors in the following alarm situations:
- Low quality power supply voltage: not allowable voltage surges and fluctuations, phase loss, wrong phase sequence, phase imbalance of phase/line voltage, phase coincidences (short circuits);
- Mechanical overloads (symmetrical overload in phase/line currents);
- Exceeding the threshold for reverse current sequence;
- Non-symmetry of the phase currents in the absence of overload which may happen either due to fault of insulation of the motor coils or the power supply cable. UBZ-302 performs comparison of non-symmetry coefficient for reverse sequence current with the non-symmetry coefficient of the voltage on the reverse sequence.
- Disappearing of the drive torque of the motor shaft (dry stroke for the pumps) – protection on the minimal starting current and/or operation current;
- Long lasting motor start or blocked rotor (rotor jamming);
- Checking the level of insulation between the stator and motor case before the motor start (winding insulation);
- Earth leakage protection of stator coils during the motor operation;
- Thermal overload protection for the motor (I2t);
- Overheating protection for the motor coils. UBZ-302 performs temperature monitoring using built in to the motor temperature sensors or the temperature of the motor case could be measured with the use of external temperature sensors (2 Nos. RTD inputs).
- For every type of protection mentioned above it’s possible to set individually the auto-reclosing (auto-reset)parameters (allowed or not allowed to start the motor automatically after certain type of fault or alarm situation).
- UBZ-302 performs protection of a motor or equipment by operating with the magnetic coil of contactor which in its turn commutates the required power load.
- UBZ-302 has 2 output relays: power load relay and functional (programmable) relay. Presence of 2 output relays gives the possibility to arrange DELTA/STAR switching without additional timer, turn ON with the delayed start (cascade turn ON of motors) and remote signalization. UBZ-302 detects the presence of the currents when the power load relay contacts are open and when the functional relay is in the DELTA/STAR mode. If these currents are detected then UBZ-302 indicates the fault of the external contactor that turns motor ON. UBZ-302 will keep on indicating this fault until it will not be de-energized (turned OFF).

- Real time monitoring of all parameters, data-logging, programming of more than 70 parameters can be done through computer software provided free of cost with the device as well as from the front panel.

- All numeric relay functions and controls available in the device.
DATA TRANSMISSION (SCADA)
- control operation and data transmission using RS-485 interface in accordance with MODBUS protocol,
- control operation and data transmission using RS-232 interface.

UBZ-302 protects the electric motors in the following alarm situations:
- Low quality power supply voltage: not allowable voltage surges and fluctuations, phase loss, wrong phase sequence, phase imbalance of phase/line voltage, phase coincidences (short circuits);
- Mechanical overloads (symmetrical overload in phase/line currents);
- Exceeding the threshold for reverse current sequence;
- Non-symmetry of the phase currents in the absence of overload which may happen either due to fault of insulation of the motor coils or the power supply cable. UBZ-302 performs comparison of non-symmetry coefficient for reverse sequence current with the non-symmetry coefficient of the voltage on the reverse sequence.
- Disappearing of the drive torque of the motor shaft (dry stroke for the pumps) – protection on the minimal starting current and/or operation current;
- Long lasting motor start or blocked rotor (rotor jamming);
- Checking the level of insulation between the stator and motor case before the motor start (winding insulation);
- Earth leakage protection of stator coils during the motor operation;
- Thermal overload protection for the motor (I2t);
- Overheating protection for the motor coils. UBZ-302 performs temperature monitoring using built in to the motor temperature sensors or the temperature of the motor case could be measured with the use of external temperature sensors (2 Nos. RTD inputs).
- For every type of protection mentioned above it’s possible to set individually the auto-reclosing (auto-reset)parameters (allowed or not allowed to start the motor automatically after certain type of fault or alarm situation).
- UBZ-302 performs protection of a motor or equipment by operating with the magnetic coil of contactor which in its turn commutates the required power load.
- UBZ-302 has 2 output relays: power load relay and functional (programmable) relay. Presence of 2 output relays gives the possibility to arrange DELTA/STAR switching without additional timer, turn ON with the delayed start (cascade turn ON of motors) and remote signalization. UBZ-302 detects the presence of the currents when the power load relay contacts are open and when the functional relay is in the DELTA/STAR mode. If these currents are detected then UBZ-302 indicates the fault of the external contactor that turns motor ON. UBZ-302 will keep on indicating this fault until it will not be de-energized (turned OFF).

- Real time monitoring of all parameters, data-logging, programming of more than 70 parameters can be done through computer software provided free of cost with the device as well as from the front panel.

- All numeric relay functions and controls available in the device.
DATA TRANSMISSION (SCADA)
- control operation and data transmission using RS-485 interface in accordance with MODBUS protocol,
- control operation and data transmission using RS-232 interface.