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-   -   Power supply for the PMDX-122 Parallel breakout board - 9V AC from main transformer (http://www.mechmate.com/forums/showthread.php?t=827)

bradyaero Wed 09 January 2008 14:54

Power supply for the PMDX-122 Parallel breakout board - 9V AC from main transformer
 
The 9v ac is for the pmdx-122. I'd like to get a coil with that tap included if possible.

Thanks, Greg

Gerald D Wed 09 January 2008 22:11

We have just wound a couple of coils of insulated wire onto(through?) the main toroidal transformer to get the 9V. It is so simple that I am kicking myself for having bought a special small 9V transformer in the first place.

GregA Fri 18 January 2008 17:08

My plan was to power the PMDX-122 with the USB port. Take a surplus USB cable, isolate the power wires and polarity, and tie them into the 5 volt output on the antek power supply. Then plug the USB into the PMDX-122. I have powered other devices this way in the past. Watch my thread, and see if it works. I should be performing a simulation in the next couple of days.

smreish Sat 19 January 2008 05:34

Hey ya'll.
When I ordered my transformer the 600W, 56V I also ordered the 12V and 5V taps with it. No real cost difference. I paid 150$ with shipping. The hope was that I could have the ability to change out to the NCpod after a while if necessary and have the right voltages available. Also, the 12V helps due to the PLC or Programmable relays require 12 to 28 Volts for operation.
Just my 2 cents.

bradyaero Sun 20 January 2008 20:59

Can you use a 12v tap with the 9v PMDX-122?

Gerald's idea sounds great if it's just a few wraps of wire to get the 9v. The idea of powering up with a USB port is also interesting if that can work out.

Thanks, Greg

Gerald D Sun 20 January 2008 22:47

What I don't like about the powering to the USB port, with a cable from the PC, is the fact that there has to be another cable from the PC to the control box. Also, I am nervous that this could introduce some "ground loops".

GregA Mon 21 January 2008 06:21

I am connecting the usb cable to the 5v lead from the Antek power supply. Only thing for me right now is... I think I know the polarity coming off of the Antek, but I'm not 100% certain, and the PMDX-122 seems like the type of device that would give off magic smoke if connected with the wrong polarity.

I also agree, just wrapping some wire around the transformer until it reads 9 volts is ingenious.

J.R. Hatcher Mon 21 January 2008 06:28

"I also agree, just wrapping some wire around the transformer until it reads 9 volts is ingenious."


CAUTION Until this is fed through a bridge rectifier it is AC current.

Gerald D Mon 21 January 2008 06:43

1 Attachment(s)
AC Power is accepted by the PMDX-122 - no rectifier needed:

Attachment 825

GregA Mon 21 January 2008 09:15

Gosh, if the 9v input takes AC, less risk of releasing the magic smoke if I connect it that way...

Gerald D Mon 21 January 2008 10:07

1 Attachment(s)
Here is the AC, direct from a transformer, connected to our PMDX-122:


The actual AC voltage is higher than 9V, but Steve Stallings of PMDX was happy with it - explained in the PMDX-122 thread.

bradyaero Wed 13 February 2008 11:51

I wrapped 18 turns of #24 around my torroidal and got 7.6v AC from it. Great idea Gerald!

Gerald D Wed 13 February 2008 12:41

So you are getting 0.422 volts per turn. 21 turns will give you 9Volt

Other transformers will be different. It is a simple case of wrapping some turns, measuring the voltage per turn, and then calculating how many more/less turns to make.

Gerald D Mon 01 December 2008 09:56

Magnet wire is the right stuff to wrap around the transformer.

An economical buy from Radioshack: three small spools (Use the 22 gauge for 1 amp)

Can also be purchased from McMaster-Carr but you will have plenty left over due to their spool sizes.

domino11 Mon 01 December 2008 15:00

If anyone needs some magnet wire in North America, just let me know and I can send you a sample to do your winding. :)


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