Changing the polarity of electromagnet using H-Bridge

Discussion in 'The Projects Forum' started by enterprize, Jan 22, 2014.

  1. enterprize

    Thread Starter New Member

    Jan 16, 2014
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    I have made an electromagnet using copper coil of 1.0 mm diameter, ferit core of 2 cm dia & 8 cm length for my project. Supplied voltage limit is 12 VDC and current it consumes is 9.0 Amp. My power supply can provide up to 30 Amps, more amps consumed by e-magnet will be welcomed too. It has 1.5 Ohm resistance. I want to change the polarity of electromagnet like pulsing. The frequency of pulsing is somewhat like Morse code or may little bit more time between two successive pulses. I have to control e-magnet pulsing through arduino uno.

    I learned H-Bridge is a way to do it. What h-bridge should i use for this amount of current and voltage? What precautions should I take when connecting the H-Bridge to arduino if any? Any other things related to doing changing polarity of e-magnet if pointed out will be of great help for me
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    How about using a DPDT Relay if the pulse is like around 1Hz
    But for higher frequency H Bridge should be used.
     
  3. enterprize

    Thread Starter New Member

    Jan 16, 2014
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    I have not used DPDT but they appear manual kind of switches. I am doing a microcontroller based automated project, this doesn't suite me. I think H-Bridge is one I need. Please answer me for that about my above problem.
     
  4. strantor

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    Oct 3, 2010
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  5. nedix

    New Member

    Jan 21, 2014
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  6. R!f@@

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    DPDT are relays. uC can switch relays without a problem.

    Still you would need to find a H bridge with 10Amp capacity or even more.
    I believe power MOSFETs should be used to drive such high current loads.
     
  7. R!f@@

    AAC Fanatic!

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    Make or buy this
     
  8. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Big voltage spikes will be generated when the solenoid current is reversed. You will need to include appropriately rated spike-suppression diodes in the circuit.

    BTW, if your supply is 12V and your solenoid resistance is 1.5 Ohms the max current will be 8A (regardless of the supply being capable of 30A).
     
  9. enterprize

    Thread Starter New Member

    Jan 16, 2014
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    @[​IMG] strantor: writing mistake, core is pure iron.
     
  10. enterprize

    Thread Starter New Member

    Jan 16, 2014
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    @nedix: H-Bridge in that are in market what I found support far less current than I require. Something like 2 amp.
     
  11. nedix

    New Member

    Jan 21, 2014
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    But you could use the current to drive either some MOSFETs or an optocoupler-triac combo, isn't it?
     
  12. Kermit2

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    Feb 5, 2010
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    If you need a simple circuit, then

    [​IMG]
     
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