Protection Relays

Protection Relays
Protection Relays
Protection relays are electronic components designed to prevent unnecessary trips, isolate faults and protect motors, breakers, and other equipment.

Modern protective relays are microprocessor-based, and use inputs and settings to intelligently compare measurements to setpoints and produce a desired output. Inputs can include variables like current, voltage, resistance and temperature. If any of those values exceed a prescribed setpoint, the relay can trigger an output like an alarm, an indicating light, a network communication, and even turn another device on or off.

Because modern protection relays use digital technology to operate, they can produce quick, reliable, repeatable outputs far more frequently over a longer lifetime. They also provide better accuracy to eliminate nuisance trips, reduced maintenance needs to improve uptime, and better efficiency to cut costs and save panel space.

460 Series Image
  • Protects From Loss of Any Phase
  • Protects From Phase Reversal
  • Protects From Rapid Cycling
  • Compact Design
  • Standard Surface or DIN Rail Mountable
The Model 460 is designed to protect 3-phase motors from damaging power conditions. The 460's wide operating range combined with UL and CE compliance enables quick access to domestic and global markets.
201A Series Image
  • Protects From Low Voltage
  • Protects From Reverse Phase
  • Diagnostic LED
  • Optional High Voltage Protection
  • 8-Pin Plug-In
The 201A is an auto ranging 8-pin, plug-in voltage monitor designed to protect 190-480VAC, 3-phase motors regardless of size. It is used to prevent damage caused by single-phasing, low voltage, phase reversal and voltage unbalance conditions.
SLA Series Image
  • Monitors Delta or Wye Systems
  • Monitors up to 480 VAC
  • Fixed, Lock Shaft, or Screwdriver Adjustment
  • Automatic Reset with Manual Option Available
  • Plug-in or Surface Mount Styles
With normal operating voltages applied in the proper ABC sequence, the internal relay will energize. When incorrect phase sequence or phase loss occurs, or the three-phase voltages fall below the drop-out voltages, the relay will de-energize.
When a phase is lost while the motor is running, a condition known as regeneration occurs where a voltage is induced into the open phase nearly equal in magnitude to the normal phase-to-phase voltage. However, with the exception of lightly loaded motors, enough change is detected by the SLA to provide the required protection when properly adjusted.
Protects against:
  • Phase Loss
  • Under Voltage
  • Phase Reversal
777 Series Image
  • Network Programmable
  • Programmable with 9-volt battery prior to installation
  • Automatic reset with 3 seperate restart delay timers
  • RS-485 communications port
  • 3-digit LED diagnostic display
SymCom's Model 777-P2 is a fully programmable electronic overload relay. It is designed to monitor and protect any 3-phase, 200-480VAC motor drawing 2-800 full load amps (external CTs are required above 90 amps). It provides unsurpassed protection from faulty voltage, underload and overload conditions.
The 777-P2 incorporates a 3-digit LED display that is used for programming, providing real-time operational information and displaying diagnostic codes to aid in troubleshooting a fault condition.
Protects 3-phase motors from:
  • High Voltage
  • Low Voltage
  • Reverse-phase
  • Current unbalance
  • Ground fault, Class II
ECS Series Image
  • Selectable over or under current sensing
  • Toroidal through hole wiring
  • 0.5 - 50A trip points
  • Adjustable or factory fixed trip delays
  • Isolated, 10A, SPDT output contacts
  • 5% trip point hysteresis (dead band)
The ECS Series of single-phase AC current sensors is a universal, overcurrent or undercurrent sensing control. Its built-in toroidal sensor eliminates the inconvenience of installing a stand-alone current transformer. Includes onboard adjustments for current sensing mode, trip point, and trip delay. Detects over or undercurrent events like; locked rotor, loss of load, an open heater or lamp load, or proves an operation is taking place or has ended.
HX00 Series Image
  • Reliable
  • Ideal for directdrive units
  • Low setpoint
  • Installation flexibility
  • Electrical load status
  • Direct-drive units,exhaust fans,process motors,and other fixed loads
  • Lighting run times and status
  • VFD output On/Off status
  • Direct-Drive units,unit vents,fan coil units,exhaust fans,and other fixed loads
Hawkeye Hx00 on/off current switches provide a cost-effective solution APPLICATIONS for monitoring status on unit vents,exhaust fans,recirculation pumps,and other fixed loads where belt loss is not a concern.
PLMU Series Image
  • Protects against phase & reversal; & over, under & unbalanced voltages
  • Octal plug-in
  • Isolated, 10A, SPDT output contacts
  • Operates from 200 to 480VAC
  • LED indicator glows green when voltages are acceptable, red for faults
  • Indicates reverse-phase wiring
  • Simple 3-wire connection for delta or wye systems
The PLMU Series continuously measures the voltage of each of the three phases to provide protection for 3-phase motors and sensitive loads. Its microcontroller senses under and overvoltage, voltage unbalance, phase loss, and phase reversal. Protection is provided even when regenerated voltages are present. Universal voltage operation and standard base connection allows the PLMU to replace hundreds of competitive part numbers.
SLU100 Series Image
  • Monitors Both Delta and Wye Systems
  • Monitors up to 550 VAC
  • Automatic or Manual Reset
  • Adjustable Fault and Restart Delays
  • Din Rail or Surface Mount Options
The SLU Series multi-mode phase monitoring relay was designed fo the convenience of electricians, maintenance managers, and engineers. A single SLU Phase Monitoring Relay can be easily adjusted for the voltage, imbalance percentage, and time delay requirements to protect against unbalanced voltages or single phasing, regardless of any regenerative voltages.
102A Series Image
  • Protects From Loss of Any Phase
  • Protects From Low Voltage
  • Surface Mount with Optional DIN Rail Mount
  • Finger Safe Barrier Strip Cover
The Model 102A is an auto-ranging voltage monitor designed to protect 3-phase motors regardless of size. It is used on 190-480 VAC, 50 to 60 Hz motors to prevent damage caused by single phasing, low voltage, phase reversal, or voltage unbalance.
250A Series Image
  • DPDT Contacts
  • Diagnostic LED
  • Adjustable Restart Delay
SymCom’s 250A series “MotorSaver” is an auto-ranging voltage monitor designed to protect 3-phase motors from damage caused by incoming power problems. Compatible with 190 to 480 VAC motors of any size, the 250A uses microprocessor-based technology and sophisticated phase-sensing circuitry to constantly monitor 3-phase voltage and detect harmful line power conditions.
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