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WR-4040, WR-4075
Transformer Power Supplies

transformers

  • Transformers provide the switching power for Douglas 2-wire relay control systems
  • Since Douglas 2-wire relays only require power to switch ON or OFF, one transformer can power many relays and control devices. In most cases, only one transformer is needed in a relay panel
  • Standard Duty Transformer (WR-4075 Series): 40VA steady draw, 74VA pulsed draw; 120/277V primary (USA), 120/347V primary (Canada); 24V secondary; automatically-resetting internal thermal fuse
  • Light Duty Transformer (WR-4040 Series): 40VA steady draw, 40VA pulsed draw; 120V primary; 24V secondary; one-time-event internal fuse
  • All Douglas transformers are current limiting, permitting the use of light gauge wire
  • WR-6161 relays have a UL-certified short circuit current rating (SCCR) of 14,000A.

    • For more information:
    Transformers.pdf