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So I am making a circuit with a simple 12v dc motor in series with an NO microswitch and on off switch conntected to a dpdt switch to reverse the polarity of the motor. The first issue I had was to find a way to connect a microswitch to only work in the reverse position, and through trial and error, I connected the switch between the negative side of the battery and motor, this set up works however the batteries keep draining current (getting hot) I'd just like to ask what am I doing wrong, and is there any other method using the components used, I've attached a simple drawing (apologies for the quality).

schematic

simulate this circuit – Schematic created using CircuitLab

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    \$\begingroup\$ I can't see the image, but make sure your switch doesn't short out the battery in any position. \$\endgroup\$ – DerStrom8 Mar 14 '17 at 20:55
  • \$\begingroup\$ Can you see the image now? The problem is that it's doing exactly what I require but just makes the batteries get to hot. \$\endgroup\$ – Mcccccc Mar 14 '17 at 21:17
  • \$\begingroup\$ I think that the fact that it's doing what you want is a fluke. It's sheer chance. And it's not doing it the way it should. It's doing what you want by shorting something out \$\endgroup\$ – DerStrom8 Mar 14 '17 at 21:28
  • \$\begingroup\$ Your redrawn schematic is wrong. SW3 connects directly between the battery terminals, and works by shorting out the battery. \$\endgroup\$ – WhatRoughBeast Mar 15 '17 at 0:22
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Without knowing the pinout of your DPDT switch it's difficult to say for sure, but from the image it appears you are indeed shorting out your battery through the switch. I also don't see how the microswitch is working. Can you try to redraw your circuit using standard schematic symbols? It will be much easier to see and understand the functionality of your current setup.

A standard motor reversal configuration using a DPDT switch is shown below:

enter image description here

Please provide some clarification of what you are trying to do with your microswitch. As described, it does not make much sense. If you intend for the motor to only run in reverse if the DPDT switch is set to "reverse" AND the microswitch is closed, then you can put the microswitch between the opposite corner terminals of the switch in the above graphic (replace one of the diagonal wires with the switch).

EDIT: Updated recommended circuit diagram:

enter image description here

Note that both micro switches are configured to be NC (normally closed).

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  • \$\begingroup\$ iv'e tried as best i can to draw the schematic i have posted it in the question, regards \$\endgroup\$ – Mcccccc Mar 14 '17 at 21:56
  • \$\begingroup\$ So basically the vehicle must go forwards and reverse and i need the sw3 switch ( Normally open microswitch) to only work when the motor is reversed if that makes sense, so when the dpdt is forwards the switch is disabled; in reverse switch can have effect. \$\endgroup\$ – Mcccccc Mar 14 '17 at 22:00
  • \$\begingroup\$ You still don't explain what effect you want the microswitch to have...? \$\endgroup\$ – DerStrom8 Mar 14 '17 at 22:05
  • \$\begingroup\$ Ok, there's another problem, never put a potentiometer in series with a motor circuit. That's a good way of burning it out. \$\endgroup\$ – DerStrom8 Mar 14 '17 at 22:08
  • \$\begingroup\$ apologies, when in reverse the micro switch (sw3) should make the vehicle stop, hence stopping the movement of the motor, interrupting the whole circuit \$\endgroup\$ – Mcccccc Mar 14 '17 at 22:08
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Reverse your DPDT switch to switch polarity to motor. And put your microswitch on source side of battery.

schematic

simulate this circuit – Schematic created using CircuitLab

Test with a meter to see if voltage changes polarity and circuit behaves as you want.

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