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Electronics => Electronics => Topic started by: VegaObscura on June 22, 2009, 03:43:20 AM

Title: Switch For Reversing Polarity
Post by: VegaObscura on June 22, 2009, 03:43:20 AM

I have a switch, a battery, and a DC motor.  What I'm trying to achieve is to make a circuit so when the switch is in one position, the motor turns clockwise and when the switch is in the other position, it turns counter clockwise.  It sounds like a very easy and basic thing to do, but I feel very dyslexic when I think about how to do it.  I'm not sure if it even can be done without more components.  I'm sure this was a problem that everyone ran into as a beginner.

Title: Re: Switch For Reversing Polarity
Post by: Joker94 on June 22, 2009, 04:55:43 AM

it depends on what type of switch it is. I'll guess that you have a twoway momentary switch like on this pagehttp://www.dse.com.au/cgi-bin/dse.storefront/4a3f61120acfa736273fc0a87e010688/Product/View/P7689 (http://www.dse.com.au/cgi-bin/dse.storefront/4a3f61120acfa736273fc0a87e010688/Product/View/P7689)

1,connect the motor leads to the middle two pins
2,connect a postive and a negative to the top two pins and in the reverse order to the bottom two pins

 i attached a drawing, hope it helps. i am having problems with eagle

Title: Re: Switch For Reversing Polarity
Post by: VegaObscura on June 22, 2009, 05:22:05 AM

My switch has only three pins.  I meant to include that in the original article.  The same concept (or a very similar one) should apply when using 2 buttons.  When one button is pressed the motor should spin clockwise and when the other button is pressed it should spin counter clockwise.

Title: Re: Switch For Reversing Polarity
Post by: Joker94 on June 22, 2009, 05:29:10 AM

i'm not sure that will work as both motor cables have to linked to the power supply at the same time

Title: Re: Switch For Reversing Polarity
Post by: Joker94 on June 22, 2009, 05:31:12 AM

i'll sleep on it, you may have to go with a six pin. :-\

is that a problem ??? 

Title: Re: Switch For Reversing Polarity
Post by: VegaObscura on June 22, 2009, 07:46:56 AM

Whether or not its a problem depends on whether or not I can find one to salvage from an old appliance.  I don't think I will be able to, but it will only stop this one project which was merely for learning anyway.  If I cannot make it work I will move on to my next project.

Title: Re: Switch For Reversing Polarity
Post by: SmAsH on June 22, 2009, 10:20:33 AM

you will need a dpdt (double pole double throw) switch, in laymans terms "one with six legs".

so, when the switch is up the current is flowing directly from the battery to the motor with + on the left and - on the right. when the switch is down the + and - go across the diagonal jumpers so + is now on the left and - on the right.
thus switching the way current is flowing through the motor.