Current Monitoring Relays: An Extra Layer of Equipment Protection

Posted on Tuesday Aug 30, 2022 at 12:47PM  

Current monitoring relays are an inexpensive solution for protecting mechanical equipment from electrical overloads and predicting risks before they cause damage. They accomplish this by monitoring the input and output currents passing through the circuits of your facility for warning signs such as:

  • Overvoltage or undervoltage
  • Overcurrent or undercurrent
  • Phase issues (out-of-sequence, failures, asymmetry)
  • Problems with power factor or active power

Those signs can tip you off to all sorts of mechanical problems with wiring or equipment such as motors, belts, fans, ventilators, pumps, and more.

Protective Applications For Current Monitoring Relays 

By monitoring electrical parameters, relays arm you with the insights you need for preventative maintenance or improvements in facility efficiency. You’ll also be able to stop expensive damage in its tracks. An increased current, for instance, could indicate a jam-up that would burn out a motor…unless your current relay is watching and stops the motor. Common applications include:

  • Isolating high-voltage wiring from control wiring
  • Monitoring and troubleshooting control wiring
  • Managing mechanical devices such as fans, ventilators, pumps, and others
  • Alerting you of warning signs or risks to mechanical devices, transformers, and other electrical equipment
  • Correcting for conditions such as jams or high loads without tripping motor overload protection
  • Detecting no-load conditions and shutting down equipment (such as pumps) to prevent burnout
  • Detecting bearing wear, heating element failure, belt slippage, or breakages, shutting down the equipment, and alerting maintenance

Are Relays the Same as Current Sensors or Switches?

Terms like sensor, relay, switch, and transducer are sometimes used interchangeably and they’re often used in very similar applications. While they all offer easy ways to retrieve, organize, and analyze the trends in your building’s systems, each also serves a unique function. 

  • Sensors are input devices that do nothing on their own. They function to read a physical quantity and turn it into an electrical quantity to help you monitor equipment. A current monitoring sensor can, however, be included with your relay in the same box — a useful combination if you’re looking to save money (and space).
  • Switches and relays are very similar in function. While a relay is not a current switch on its own, it controls a switch that could be located elsewhere. Relays will trip current switches in the event that certain parameters are met.
  • Relays are output devices that are used to switch high voltage/high current loads using low voltage/low current circuits. They also offer advantages such as physical separation and multiple wiring exits to isolate wires with differing loads. 
  • Transducers are used in monitoring electrical loads, like relays, but their role is different. The purpose of the current transducer is to transform the conductor’s raw input into a standard digital signal that’s generally more useful to building systems and software.

Current Monitoring Relays From Veris

Our Hawkeye 5xx Series combines an industrial-grade load-switching relay, current status switch, and Hand-Off-Auto (HOA) switch in an easy-to-install remote enclosure. This makes the Hawkeye ideal for monitoring, directly controlling, and troubleshooting the control wiring of fractional horsepower motors. 

Some models combine a relay, current sensor, and HOA switch in a single series circuit. Wire it in series between the power source and the motor, and you’ve got all the components you need installed. Three devices, one line connection. Read more on the datasheet or get in touch with a Veris expert for more information!

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