We managed to control 2 DC motors with 2 relays for each one.It worked great except one thing: we couldn't make them turn in opposite directions at the same time .We noticed that there was a shot circuit. Can somebody explain it please? Thank you for your attention.

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    \$\begingroup\$ Please add a schematic of your setup, and add some information about the relays you've been using. \$\endgroup\$ Sep 9, 2014 at 11:26
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    \$\begingroup\$ You can control the direction of a motor with a single relay, but it must be a double pole one. \$\endgroup\$ Sep 9, 2014 at 11:49
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    \$\begingroup\$ Google: 'h-bridge motor direction' \$\endgroup\$ Sep 9, 2014 at 12:01
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    \$\begingroup\$ You obviously messed up the wiring, since if you can drive one motor with two relays, you should be able to drive any number of motors with two relays each (up to the capacity of the power supply, of course). ... Unless the motors have hidden (internal) connections between their power terminals and their cases, which could create a short through their mountings. \$\endgroup\$
    – Dave Tweed
    Sep 9, 2014 at 13:15
  • \$\begingroup\$ No one who posted comments or answers seems to have had much difficulty in either understanding the OP's query or asking for further information, so why are a few non-contributors to the thread putting the question on hold? \$\endgroup\$
    – EM Fields
    Sep 9, 2014 at 17:16

1 Answer 1


Here's one way to do it; where's the short?enter image description here


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