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Q & A: Reversing motors

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Most recent answer: 10/22/2007
Q:
I am trying to make a simple reversing circuit. Where a motor will go a certain distance and then reverse and go the other way. Similar to a human head turning side to side. I have even gone so far as to purchase a dancing gopher that has a turning head similar to what I need, but there is a RC timer or an IC chip timer in the circuit. I have been unable to find it. So I am back to trying to make a circuit to accomplish my goal. Any help? I could really use it.
- David Gruszynski
Milwaukee technical college, WI, USA
A:

You may be best off with a mechanical solution. I’d recommend using a mini switch which has a roller or other projection which detects when your object has reached the end of its intended motion. This switch can be then used to energize a relay which can direct the current to the motor. A three-pole permanent magnet motor will spin in one direction or the other depending on the polarity of the power supplied, and the relay is used to make the appropriate switch to the motor. Stop by an electronics supply store to find mini switches, relays, motors, and diagrams.

Here is an electricity-3-pole DC electric motor: http://www.dynamicscience.com.au/tester/solutions1/electric/3poledcmotot.html.

Using a timer may cause "wander" if the motor is to reverse many times and it for some reason does not travel as far forwards as it does backwards, and the errors accumulate over time.

Tom


(published on 10/22/2007)

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