Product Details:

Power (Watts or HP)2.5 – 315 kW (4 – 500 HP)
Motor Voltage415 V AC
Motor BrandAny
PhaseThree Phase
Speed (Rpm)Any
Voltage TypeAC
Operating Voltage (V)320 – 480 V
Number of Poles3 Pole, 4 Pole
ApplicationThree phase LT motor protection with CTs and CBCT
Rated Current (Amps)5A – 50A, 10A – 100A, 63A – 630A selectable
Output TypeSPDT (1NO + 1NC) potential free

Universal Protection Devices For Asynchronous Electric Motor. UBZ-301 universal electric motor protection unit (further referred to as the unit) is designed for continuous monitoring of the circuit voltage parameters and phase/line RMS currents of three-phase 415V/50Hz AC electrical equipment, primarily, of induction asynchronous motors (EM) with wattage rating from 2.5kW up to 315 kW, as well as those with isolated neutral line. Three device versions are manufactured, with differentiation by current ratings: UBZ-301 5-50A, UBZ-301 10-100A and UBZ-301 63-630A The unit provides full and effective protection of electrical equipment by de-energizing and/or disabling its start in the following cases: when the mains voltage is of poor quality (unallowable voltage surges, phase loss, incorrect phase sequence and phase

Additional Information:

  • Item Code: UBZ-301 (X-XXA)
  • Port of Dispatch: New Delhi, India


Nominal line voltage, V415
Mains frequency, Hz45-55
Harmonical configuration (nonsinusoidality) of power supply voltageEN 61000-3-2 (IEC 1000-3-2)
Nominal current range in UBZ-301 5-50А, 10-100A, 63-630A5-50, 10-100, 63-630
Operating current setting range, % of nominal±15
Double overload delay adjustment range, sec10-100
Voltage threshold adjustment range, % of nominal±(5-20)
Phase imbalance adjustment range, %5-20
Trip threshold adjustment range for the minimum current, % of nominal0-75
Automatic reset delay adjustment range ( Тon), sec0-600
First energization load delay when Тon= 0, sec2-3
Trip delay for current overloadAccording to current-time characteristic curve
Trip delay for voltage fault, sec2
Trip delay for current fault (overload excluded), sec2
Fixed trip point for leakage current, А0.5
Insulation resistance threshold, kОhms500±20
Voltage hysteresis, V10/17
Heat hysteresis, % of stored-up heat after load de-energization33
Trip threshold accuracy for current, % of nominal current, not more than2-3
Trip threshold accuracy for voltage, V, not more than3
Phase imbalance accuracy, %, not more than1.5
Operating voltage range, % of nominal one50-150
Power consumption (under load), VA, not more than3.0
Maximum switched current of output contacts, A5

Output contact life:
– under 5A load , operations, no less than

– under 1A load , operations, no less than

100 000
1 000 000
– apparatus
– terminal block
Operating temperature range, °Cfrom -35 to +55
Overvoltage categoryIII
Nominal voltage of isolation, V450
Nominal impulse withstanding voltage, kV4
Cross section of wires of connection terminals, mm²0.5-2
Maximal tightening torque of terminals external screws, N*m0.4
Allowable soil levelII
Weight, kg, not more than0.200
Case dimensions    4 modules of S-type
Mounting  standard 35 mm DIN-rail
Mounting position  arbitrary

The output contacts specification:


Max. current for
~ 250 V A. C.

Max. powerMax sustained safe voltage ~

Max. current for
U = 30V D.C.

Cosφ = 0.4



Cosφ = 1.0


UBZ-301 complies with requirements of IEC 60947-1, ІEC 60947-6-2, CISPR 11, IEC 61000-4-2.