single switch reversing dc motor

[cejay825]

Hello guys,my elctronics background is only decent but not completely ignorant.I need some help with a circuit.With a single switch(spst)control I need a 12vdc low amp(automobile window lift) motor to turn on and run in one direction for 2 seconds then stop, upon closing the switch the motor needs to turn on in the opposite direction and run for 2 seconds then turn off.The motor in question has two leads, reversing leads reverses direction.ANY help would be great! Thanks so much.

 

[walker1]

My 1st bet would be a full-bridge (four transistors or four relays), where you control them two and two in diagonal.
(It could be done with a half-bridge if you had +/-12V, but that's not available in a car, I guess

With the motor placed across the bridge you can control on/off and direction.

Exactly what to do, when the state of the switch is changed, can then be done in digital (micro-controller ?).

 

[ScottyUK]

Hi walker1,

You could do it with a DPDT reversing relay and a SPST on/off relay, saving two relays.






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If we learn from our mistakes,
I'm getting a great education!

 

[cejay825]

scotty,
Thats the original way I built it and it works well, but I would have to install two time delys for the 2 second intervals, one for forward and one for reverse. Then I started thinking would it be better to go solid state or IC. I have no problem with the way it is, I was just wondering if there was a more effient way.

 

[felixc]

There are bridges available, precisely for this usage. They are called H-bridges. Do a search with this name and you'll find a lot of info, designs as well as parts.
The Infineon TLE5205 is an example of such a H-bridge single-chip that controls up to 5 amps.
Felix