M-3310 Transformer Protection System

Please Note: As of 12/31/2022, Beckwith Electric will no longer be manufacturing the M-3310 Transformer Protection System.

  • Beckwith will accept orders for these products until 8/31/2022 and all products ordered must ship before 12/31/2022.
  • Please contact us to request a quote and place orders.
  • This product may have an alternative replacement product, M-3311A, depending on your application needs. Please contact us for details.


  • Fully Digital Multifunction Relay with eight programmable outputs, six programmable inputs, and four multiple setpoint groups
  • Suitable for two-winding transformers of any size, and some three-winding applications
  • Windows-based software offers extensive graphics for easy inservice commissioning
  • Optional three-phase Voltage Protection Package available

Standard Protective Functions

  • Negative-sequence inverse time overcurrent (46)
  • Two winding, dual element instantaneous overcurrent (50W1 #1, 50W1 #2, 50W2 #1, 50W2 #2)
  • Breaker Failure (50BF)
  • Transformer neutral, instantaneous/inverse time overcurrent (50G/51G)
  • Two winding inverse time phase overcurrent (51W1/51W2)
  • Residual, inverse time overcurrent (51NW1/51NW2)
  • Two winding, phase differential (87T) and High Set instantaneous (87H)
  • Ground differential (87GD)
  • Six External functions with individual timers

Optional Three-Phase Voltage Protection Package

  • Overexcitation (24) V/Hz
  • Phase undervoltage (27) function for load shedding
  • Neutral overvoltage (59G)
  • Underfrequency (81U)

Standard Features

  • Multiple Setpoint Groups
  • Eight programmable outputs and six programmable inputs
  • Oscillographic recording
  • 32-target storage
  • Real time metering of measured parameters, with demand and maximum values
  • Two RS-232 and one RS-485 communications ports
  • Standard 19″ rack-mount design
  • Removable printed circuit board and power supply
  • 50 and 60 Hz models available
  • 1 and 5 A rated CT inputs available
  • M-3820A IPScom® Communications Software
  • IRIG-B time synchronization
  • Includes MODBUS and BECO 2200 protocols

Optional Features

  • Redundant Power Supply
  • M-3910 Target Module
  • M-3931 Human-Machine Interface (HMI) Module
  • M-3801D IPSplot® PLUS Oscillograph Analysis Software
  • 4-Wire RS-485 Connection