Current Monitor Relay H540NS

Features

  • Remote mounted current status sensor and command relay without HOA switch
  • Combines status sensor, command relay in a single series circuit one line connection for three devices
  • Gang box mounting – mounts directly onto gang box, flush to existing enclosures and standalone
  • SPST relay is field-selectable for NO or NC operation
  • 1 hp at 120 VAC and 1.5 hp at 277 VAC one product for all fractional HP motor control and status applications
  • Induced from monitored conductor sensor power
  • Relay power LED
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Dpstar offers a reliable current monitor relay designed for commercial HVAC and automation systems. This model integrates a current status switch and hand-off-auto (HOA) control into a compact, remote-mounted enclosure—ideal for monitoring, controlling, and troubleshooting fractional horsepower motors.

The relay, current sensor, and HOA switch are pre-wired in a series configuration, installed between the power source and motor. Once connected, all three components function as a unified control point. The enclosure is engineered to provide physical separation between control and high-voltage wiring, with multiple exit points for flexible installation. It can be mounted directly on 2- or 4-gang junction boxes, in a field enclosure, or used as a standalone unit.

Dimensional Drawing

Wiring Diagram

Applications

  • Monitoring status and controlling small motor loads that are not driven by a motor starter or contactor
  • Exhaust fans
  • Unit ventilators
  • Fan terminal units
  • Fan coil units
  • Recirculating pumps

Specification

Model H540NS
Application Building Automation Systems
Current Measurement Range  0.25 – 15 A
Current Sensor type Current Transducer, AC, with Relay
Electrical Wiring Size  24 – 14 AWG (0.2 – 2.1 mm²)
Hand-Off-Auto  No
Measurement Type  AC Current
Monitored Wire Size 50 – 60 Hz
Mounting 4 x 4 Box
Operating Humidity 10 – 90% RH, non-condensing
Operating Temperature 5 – 122 °F (-15 – 50 °C)
Output Specifications N.O. 1 A @ 30 VAC/DC
Outputs Switch output | Relay
Product Certification UL
Product Type Sensor
Range Motor Control Series
Relay Coil Voltage 24 VAC/DC
Mechanical
Relay Contact Ratings Resistive: 15 A @ 277 VAC | Motor: 1 H.P. @ 120 VAC | Motor: 1.5 H.P. @ 277 VAC
Relay Poles/Throw SPST
Setpoint Fixed
Warranty 5 years

Ordering Information

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