12v power supply

Discussion in 'The Projects Forum' started by sajelectric, Sep 22, 2011.

  1. sajelectric

    Thread Starter New Member

    Aug 19, 2011
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    Hi, I am looking for a 12v 5a d.c power supply having 50ma output, to operate a relay coil and thus a 12v 5a motor. Please tell me where it is available and what is the cost? Or give me a circuit to make one.
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  3. SgtWookie

    Expert

    Jul 17, 2007
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    Let's see, you want a 12v, 5A DC power supply that has a 50mA output?

    This doesn't seem to make sense. Do you mean that it needs to have something like a "voltage good" signal in order to operate the relay coil?

    It's not good to operate a supply at 100% capacity. You should use a supply rated for more than your load.

    Also, motors draw many times as much current when stalled (or starting from a stop) than they do when running at speed with no load. Is the 5A specification the stall current or the no-load current, or something else?
     
    Last edited: Sep 22, 2011
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    I thought he just wanted a power supply to use for powering both the relay and the motor..
    Just an 12V 8A or 10A or whatever power supply. (5A+50mA+safety factor)
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Possibly the cheapest way to get a supply would be to do the "ATX bench supply" modification on a computer supply that has a suitable 12v rating.

    But, we don't know where our original poster is, so suggesting a supplier would be pointless.
     
  6. sajelectric

    Thread Starter New Member

    Aug 19, 2011
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    Its a small customized motor which draws a current 5A max.
    Also need to power a relay(load 50MA max.)
    Please suggest the best power supply can be used.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    sajelectric likes this.
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