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2H34 Four Stage Frequency Relay

The 2H34 Series relay is a frequency monitoring relay with four stages of adjustable frequency pick up & drop out points. Each frequency set point can be set for under or over frequency operation & has an independent time delay driving an output relay. An undervoltage lockout is used to disable the four frequency outputs when the voltage falls below a preset level. Each of the four setting stages has a rate of change of frequency (ROCOF) element with an independent time delay.

The dF/dt element is available to operate as an AND or an OR  logic function with the frequency element driving a common output contact per stage. A separate Under Voltage & Over Voltage stage are provided for alarm functions.

The 2H34 relay is built on the Micro MATRIX digital platform. The standard Micro MATRIX human machine interface (HMI) is combined with fully solid state frequency sensing & measuring circuitry to provide high accuracy, simple set up & flexible operation. Self-monitoring is carried out by hardware & software watchdogs.  An RS232 programming port is provided for ease of establishing relay settings using a PC.


  • Large graphics display panel
  • Instantaneous Frequency display
  • RS232 PC programming port
  • 41 to 59Hz PU setting range
  • 0.01Hz measurement resolution
  • Adjustable pick up & drop out
  • Adjustable reset time delay
  • 0.13 to 9Hz/s ROCOF function with global activation
  • Adjustable dF/dt sample time to optimize accuracy & response
  • 63.5/110V AC nominal VT inputs
  • 0.04 to 320s time delayed output with +0.5% accuracy
  • Four independent setting stages & output trip contact
  • Timing & trip indication LED's
  • Relay enable input
  • CPU watchdog
  • Undervoltage blocking function
  • Undervoltage alarm output
  • Overvoltage alarm output
  • Wide auxiliary supply range with fail alarm contact
  • Size 4 draw out case
  • Optical isolated RS232 PC link
  • Non platform specific PC programming software
  • Optical isolated RS485 or RS232 network port
  • MODBUS RTU compatible network protocol
  • Made in Australia

2H34 updated with 2H34-S

Product upgrade path LISTING


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©1998-2012 Relay Monitoring Systems Pty. Ltd.      ACN 052 484 483     ABN 76 052 484 483

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