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The HLMU Series is a universal voltage, encapsulated, 3-phase voltage monitor. It continuously measures the voltage of each of the three phases with microcontroller accuracy and compares the value to preset trip points. It separately senses phase reversal and loss; over, under and unbalanced voltages; and over or under frequency. Protection is assured during periods of large average voltage fluctuations, or when regenerated voltages are present. The unit trips within 200ms when phase loss is detected. Adjustable time delays are included to prevent nuisance tripping and short cycling of sensitive equipment. The isolated, 10A, DPDT relay contacts trip when a phase voltage exceeds the trip limits for the trip delay. Nominal line voltage, voltage unbalance, and time delays are knob adjustable. The phase loss setpoint and the acceptable frequency range are fixed. Both delta and wye systems can be monitored; no connection to neutral is required.

  • Input Voltage (V): 200-240VAC; 340-420VAC; 400-480VAC
  • Input Voltage Maximum (V): 550VAC
  • Input Type: 3-phase delta or wye with no connection to neutral
  • Input AC Line Frequency (Hz): 50/60Hz automatically detected; 240VAC: 50/60Hz; 380VAC: 50Hz; 480VAC: 60Hz
  • Input Phase Sequence: A B C L1 L2 L3
  • Output Type: Isolated electromechanical relay
  • Output Form: DPDT
  • Output Load Rating (VA): 10A resistive @ 240VAC; 8A resistive @ 277VAC; NO-1/4hp @ 120VAC; 1/3hp @ 240VAC
  • Reset Time (ms): Automatic
  • Response Time (ms): Phase loss: 200ms; Phase reversal: 200ms
  • Restart Delay Range: Adjustable from 0.6-300s; staggered restarting
  • Restart Delay Tolerance (%): 15%
  • Trip Delay Type: Active On: ver/undervoltage voltage unbalance over/under frequency
  • Trip Delay Range: Adjustable from 1-30s
  • Trip Delay Tolerance (%): 15%
  • Overvoltage Trip Voltage (%): 109-113% of the adjusted line voltage
  • Overvoltage Reset Voltage (%): -3% of the trip voltage
  • Undervoltage Trip Voltage: 88-92% of the adjusted line voltage
  • Undervoltage Reset Voltage (%): +3% of the trip voltage
  • Voltage Unbalance Trip Point (%): Adjustable 2-10%
  • Voltage Unbalance Reset (%): -0.7% unbalance
  • Over/Under Frequency (%): 4%; Reset 3%; 50/60Hz
  • Phase Loss: 25% unbalance
  • Isolation Voltage (V): 2500V RMS input to output
  • Surge Protection: IEEE C62.41-1991 Level B
  • Circuitry: Encapsulated
  • Type of Detection: Voltage detection with delayed trip and automatic reset
  • Life: Mechanical - 1 x 106; Electrical (at 10A) - DPDT - 1 x 303
  • Termination Type: Screw terminal connection for up to #12 AWG (3.3mm2) wire
  • Mounting Method: Surface mount with one #10 (M5 x 0.7) screw
  • Operating Temperature: -40° to 60°C (-40°F to 140°F)
  • Storage Temperature (F/C): -40° to 85°C (-40°F to 185°F)
  • Humidity: 95% relative non-condensing
  • Dimensions: 3.00 x 2.00 x 1.64 in. (76.7 x 50.8 x 41.7mm)
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Product Type:

Voltage Meter







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