Picking the right relay

Discussion in 'General Electronics Chat' started by Tim Blevins, Aug 15, 2016.

  1. Tim Blevins

    Thread Starter New Member

    May 27, 2016
    I need a 12 volt DPDT relay. I am using it to reverse polarity on four electric actuators operating in unison. Maximum amp draw on the actuators wired parallel is 5 amps each under a heavy load. I think I need a relay that can handle a minimum of 20 amps @ 12 volts.

    For Instance this description:
    • Coil Voltage: AC 12V;
    • Contact Capacity: AC 240V/10A, DC 24V/10A
    • Type: DPDT(2NO 2NC);
    • Pins: 8 Pin;
    • Mount Type: 35mm DIN Rail
    My question is on contact capacity.
    Contact Capacity: AC 240V/10A, DC 24V/10A

    What should I be looking for here to be adequate for the 4 actuators?? DC 24V/40A ? Or More ?
    I just need an adequate relay with socket that will mount on a DIN rail to operate the 4 actuators.
    The one above has been working adequately but I feel it may not be durable enough
    Any suggestion would be great.

  2. marcf


    Dec 29, 2014
    You may want to inspect your attached schematic diagram. It appears that when the relay is activated, a short will exist across the battery.

    Also, you may want to use the 'standard' schematic symbol for a DPDT relay.

    The actuators, being inductive should have a suppression diode across them, as should the relay coil.

    Also it is a good idea to connect the load across the C(ommon) contacts and the Power source to the NO NC contacts.