LPMR/AUX Phase Monitoring Relay

  • Phase unbalance monitoring
  • Detects incorrect phase sequence and phase loss
  • Wide 3-Phase voltage range 190 – 600VAC
  • Auxiliary supply – 24VAC
  • No user adjustments – Easy to install/set-up
  • SPNO output @ 24VAC
  • 17.5mm wide, DIN Rail mount

Designed for the protection of screw and scroll compressors against phase unbalance, loss and reversal, the product monitors a wide three-phase supply used to power the load but in addition, is powered itself from a separate 24VAC auxiliary supply.

For the relay to energise, the auxiliary supply must be connected and the all phases present, in the correct sequence and within the operating parameters specified. If any of these conditions are not met, the relay will de-energise.

 

  • Monitoring function: Phase Unbalance, Sequence + Loss
  • Monitored supply voltage: 190 – 600VAC
  • Phase unbalance loss/threshold: 67.5V +/- 2.5V*
  • Phase unbalance reset level (Hyst.) 6.5V ± 1.5V below trip level
  • Time delay (from fault): < 200ms
  • Auxiliary supply: 24VAC +/-25%
  • Output: SPNO 6A (24VAC)
  • Dimensions(mm): W:17.5 x H:89 x D:66.5

* between highest and lowest phase to
phase voltages
(Order Code: 99-4301)

Typical applications include:

  • Screw compressor systems
  • Scroll compressor systems
  • Commercial refrigeration plant
  • Packaged air-conditioning units

Key benefits:

  • Helps protect compressor operation — Phase-unbalance detection can release the control permissive when the three-phase compressor supply exceeds the documented imbalance threshold.
  • Helps prevent incorrect motor rotation — Incorrect phase sequence prevents relay energisation, allowing the compressor control circuit to inhibit operation.
  • Responds to a lost phase — Phase-loss detection de-energises the relay so an external control circuit can stop or inhibit the compressor.
  • Simplifies compressor-control setup — Fixed operating settings remove threshold adjustments, while the separate 24VAC supply and rated output suit appropriately designed auxiliary control circuits.

Alternative product:

Icon: switch product
LXPRF Under Voltage Monitoring Relay
  • Under voltage monitoring
  • Monitors own three phase, 3-wire supply
  • Detects incorrect phase sequence and phase loss
  • Fixed Trip levels and Time delay
  • SPDT Relay output
  • 17.5mm wide, DIN Rail mount
  • UL Listed
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VIDEO HERE
Download datasheet