Protection Relays

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.
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.
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.
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.
PLM Series Image
  • Protects against phase loss & reversal; & under & unbalanced voltages
  • 8-pin plug-in base
  • Adjustable low voltage trip point
  • Factory fixed unbalance & trip delay
  • Line voltages 200 to 480VAC in 3 ranges
  • Isolated, 10A, SPDT output contacts
The PLM Series continuously measures the voltage of each of the three phases. The PLM Series uses a microcontroller circuit design that senses undervoltage, voltage unbalance, phase loss, and phase reversal. Protection is assured when regenerated voltages are present. Both delta and wye systems can be monitored; no connection to neutral is required.
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.
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