Product Description

UBZ***2 is the microprocessor based digital device, reliable and of highest degree of measurement accuracy. It doesn’t require the operational external power supply since the controlled voltage at the same time is the power supply for UBZ***2. It has 3 built-in current measurement transformers through which the motor power supply wires are looped for continuous currents monitoring. Universal electric motor protection device (hereinafter UBZ***2) is designed for the continuous control of the power supply voltage, monitoring of UBZ***2 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;
- 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***2 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;
- Checking the level of insulation between the stator and motor case before the motor start;
- Earth leakage protection of stator coils during the motor operation;
- Thermal overload protection for the motor;
- Overheating protection for the motor coils. UBZ***2 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 (RTD s).
actingvalues of phase/line currents in 3 phase electrical circuits and additionally performs theresistance testto check the level of motor coils (winding) insulation. Moreover UBZ***2 is capable to work in electric circuits with isolated neutral (allows operation in both in 3 and 4 wire electric circuits). For every type of protection mentioned above it’s possible to set individually the autoreclosing parameters (allowed or not allowed to start the motor automatically after certain type of fault or alarm situation). UBZ***2 performs protection of a motor or equipment by operating with the magnetic coil of contactor which in its turn commutes the required power load. UBZ***2 has 2 output relays: DATA TRANSMISSION (SCADA):power load relayandfunctional relay. Presence of 2 output relays gives the possibility to arrangeDELTA/STARswitching, turnONwith the delayed start (cascade turnONof motors) and remote signalization. UBZ***2 detects the presence of the currents when thepower load relaycontacts are open and when thefunctional relayis in theDELTA/STARmode. If these currents are detected then UBZ***2 indicates the fault of the external contactor that turns motorON.UBZ***2 will keep on indicating this fault until it will not be deenergized (turnedOFF).- control operation and data transmission using RS***5 interface in accordance with MODBUS RTU protocol, - control operation and data transmission using RS***2 interface.