[EMS Discuss] Magnetic Device Troubleshooting

Fri Aug 30 17:44:12 PDT 2013

Thanks for the thoughts. I am going to respond to each post individually to
try and keep this organized.

1. We have re-verified our known information and it is true

2. Each of the magnets (all 4) always have 13.3 Volts across them when the
machine is on, in a standby state. The voltage does not change across a
magnet when it is powered or un-powered. I have been trying to find a
reliable current reading across each magnet when it is idle, intentionally
active and not-intentionally active. I have not been able to get a good
reading on that, I will continue to try. If I disconnect the magnet it has
no voltage or current, if I connect it then it does. Disconnecting other
parts has not effect on the second unwanted magnet powering.

3. Each magnet is getting 13.3 volts from the power supply. If I disconnect
the incorrectly active magnet it does not work anymore, no additional
incorrect magnet is active and the correct magnet is still able to be

On Thu, Aug 22, 2013 at 10:24 PM, Bob Miller <EMAIL HIDDEN> wrote:

> I have some suggestions.  They are no more than shots in the dark, but hey.
> 1. Re-verify your Known Information.  Make sure it is really true.
> 2. Measure the voltage across a magnet when it is active but should not
> be.  There is some, right?  Disconnect things until there is no voltage
> across that magnet.
> 3. You say (#5) that you can change the power wiring to the magnets.  Can
> you measure voltage coming out of the power supply to the incorrectly
> active magnet?  If you unplug that magnet from power, what happens?  if you
> unpower its twin, what happens?
> On Thu, Aug 22, 2013 at 6:45 PM, Cord Slatton <EMAIL HIDDEN> wrote:
>> Hello All!
>> I have a device that I can only say so much about due to an NDA but I am
>> having a problem with and need a bit of advice. If I have not given enough
>> info or a diagram (though I cannot be too detailed on certain aspects) is
>> needed, please let me know.
>> Thanks so much!
>> ------------------------------------------------------------------------------------------------------
>> I have Arduino based controller that turns on a single control board
>> input, which turns on one of 4 individual mosfet banks. When a mosfet bank
>> is on it allows current to flow which turns on an electromagnet.
>> The magnets are hooked to the main power bus, all the same way, one side
>> going to positive and one to negative with a mosfet bank keeping it from
>> being always on.
>> There is a bit of something in the magnet connector that is supposed to
>> cancel backflow EMF that could damage the controller, I am not positive
>> what is going on with that but it is super simple part wise, and I can get
>> the part number and post it if needed.
>> This system used to work correctly in the past the way it is wired, but
>> not when I had it in my possession.
>> Problem: When a magnet is activated another magnet is always active at
>> the same time.
>> Known Information
>>    1. The Arduino controller and the control board are working
>>    correctly. It sends a pulse to the correct mosfet bank. The correct
>>    indicator light activates and high voltage is sent to the corresponding
>>    mosfet bank.
>>    2. The mosfet banks seem to be working correctly, only the one
>>    receiving a signal activates.
>>    3. The magnet that is triggered by the controller does
>>    activate(correct behavior).
>>    4. The incorrectly triggering magnet is not triggered through
>>    induction and proximity does not matter.
>>    5. The same pairs of magnets always activate, even if rewired to the
>>    power supply in different configurations(magnets 1 & 4, 2 & 3)
>>    6. The only way to get a single magnet to activate is to remove it's
>>    paired magnet from the machine.
>>    7. The Arduino based controller I built is connected thusly: a ground
>>    wire to share the circuit's common ground and 4 control wires, each to
>>    individually turn on the pins on the device control board that drive the
>>    mosfets.
>>    8. Changing out the Arduino based controller for another control
>>    method(or manual control) does not change the behavior of the machine
>> --------------------------------------------------------------------------------------------------
>> _______________________________________________
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> --
> Bob Miller                              K<bob>
>                                         EMAIL HIDDEN
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