Elecrtic motors universal protection device UBZ-305

The UBZ-305 can operate in the mains with isolated neural as well as with solidly-grounded neutral.

The device is equipped with DIN rail.

The UBZ provides continuous control of the mains voltage parameters and RMS phase (line) currents of the three-phase electric equipment of 380V 50Hz, as well as the electric motor insulation resistance test.

The UBZ provides electric motor protection in the following cases:

•  when the mains voltage is of poor quality (unacceptable voltage fluctuations, phase interruption,  violation of phase sequence and phase coincidence, phase/line voltage imbalance, decrease of mains frequency below the specified one and (or) increase of mains frequency above the set one);
•  when mechanical overloads (symmetrical phase/line current overloads) occur;
•  when reverse sequence of the current threshold occurs;
•  when phase current imbalance (without overload) occurs that is induced by the insulation fault inside the motor and/or the lead cable (comparison of current imbalance factor with voltage imbalance factor based on negative sequence);
•  when motor torque is lost (“dry run” for pumps) – protection based on the minimum inrush and/or operating current;
•  when start delays or locked rotor occurs;
•  when insulation level between the fixed coil (stator) and frame is abnormally low (test before motor start).
•  when stator winding ground fault takes place during operation – ground leakage current protection;
•  when motor thermal overload occurs;
•  when winding overheating occurs (winding temperature is measured by the integrated temperature sensors, or frame temperature is measured by the external temperature sensors).

General specification

Application of the unit	Switchgear and control-gear; induction motor protection control
Design (installation) type	DIN rail 35 mm
Protection level	IP20
Climatic version	UHL 3.1
Operating temperature range*	from -20 to +55 °C
Contamination level	II
Overvoltage category	II
Rated voltage of insulation	450 V
Rated impulse withstand voltage	2.5 kV
Electric shock protection class	II
Wire cross section for connection to terminals	0.5-2 mm²
Torque for terminal screws	0.4 N*M
*Note: It is allowed UBZ operation at temperatures from minus 35 to minus 20°С; in this case the readings on display can be not available.

Technical Specifications

Operating supply voltage, three-phase	380 V, 50 Hz
Mains frequency, Hz	48-62
Rated current of CT, A	5
Voltage hysteresis, (phase/line), V	10/17
Thermal hysteresis, % of accumulated heat at shutdown	33
Determination accuracy of trip threshold for current, not more, in % of rated value	2
Determination accuracy of trip threshold for voltage, not more, V	3
Determination accuracy of out-of-phase voltage, not more, V	3
Voltage when maintaining serviceability: - phase voltage, when powered by one phase and zero wire is connected, not less, V - line voltage, when powered by three phases, not more, V	180 450
Main outputs: - load relay – two groups of changeover contacts to control the electric motor starter – 8A, 250 V at cos φ=1; - functional relay – one group of changeover contacts - 16A, 250V at cos φ=1 (function of the relay is set by the user).
Analog inputs: - input to connect temperature transmitter (types: Pt100, Ni100, Ni120), pc.; - input to connect temperature transmitter of PTC-1000 type, pc.; - three analog inputs for standard CT with 5A output (T-0.66 type or similar), pc.; - input to connect differential current transformer (zero sequence transformer) pc.; - input to measure current of 0-20 mA, pc.; - input to measure voltage of 0–10 V, pc..	1 1 3 1 1 1
Permit according to temperature of temperature transmitters, °C	1
Power consumption (under load), VA, not more	5.0
Weight, kg, no more than	0.34
Overall dimensions	91 х 157 х 58 mm
Position in space	free
Housing material	self-extinguishing plastic

Characteristics of output terminals of integrated relays

Dimensions