Relay Coil Energy Saver


Posted on Feb 4, 2014

Some relays will become warm if they remain energized for some time. The circuit shown here will actuate the relay as before but then reduce the hold` current through the relay coil current by about 50%, thus considerably reducing the amount of heat dissipation and wasted power. The circuit is only suitable for relays that remain on for long perio


Relay Coil Energy Saver
Click here to download the full size of the above Circuit.

ds. The following equations will enable the circuit to be dimensioned for the relay on hand: R3 = 0. 7 / I Charge time = 0. 5 G— R2 G— C1 Where I is the relay coil current. After the relay has been switched off, a short delay should be allowed for the relay current to return to maximum so the relay can be energized again at full power. To make the delay as short as possible, keep C1 as small as possible. In practice, a minimum delay of about 5 seconds should be allowed but this is open to experimentation. The action of C2 causes the full supply voltage to appear briefly across the relay coil, which helps to activate the relay as fast as possible. Via T2, a delay network consisting of C1 and R2 controls the relay coil current flowing through T1 and R3, effectively reducing it to half the pull in` current. Diode D2 discharges C1 when the control voltage is Low. Around one second will be needed to completely discharge C1. T2 shunts the bias current of T1 when the delay has elapsed. Diode D1 helps to discharge C1 as quickly as possible. The relay shown in the circuit was specified at 12 V / 400 ohms. All component values for guidance only.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Pine Racecar Victory Judge
    Soil Heater For Plants Circuit
    Mini Voice Operated Relay circuit diagram
    0-50V 1A Laboratory Power Supply Variable Voltage
    555 circuits
    PICcontroller
    single cycle datapath write to register and memory at same time
    Resurrecting Tennis for Two a video game from 1958
    GlueLogix Technical Services
    Frost Alarm
    ASTABLE MULTIVIBRATOR USING OP AMP
    Linear-Circuits in U.H.F. Oscillators



    Top