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-   702. Power Supplies (http://www.mechmate.com/forums/forumdisplay.php?f=10)
-   -   Home built power suply for MM (http://www.mechmate.com/forums/showthread.php?t=3030)

Carlos Mariche Fri 10 September 2010 01:42

Home built power suply for MM
 
Hello people, after read some threads about MM proyects I decided start my own project, at this point I´m working in the mechanical design but in parallel I´m also working in the electronic.

I saw there is a lot of options about power supplies (PS) but at the end It seems all people prefer the easy way and better buys Anteck PS.

Well, I really don´t know specifically what is the best configuration in order to have the most standard power supply to all people, it is obvius that it has to do more than anything with the type of configuration that each has for your machine. In past I have constructed some PS as my univerisity proyects, no one like MM PS, but a PS to the end of the day.

Here is where I need your help because frankly did not encourage me to buy something that maybe I can do and less with the reference Gerald gives us about Antek guys. http://www.mechmate.com/forums/showt...ight=footprint :(

The configuration that I will consider for the PS will be one based on the following arrangment of parts for a MM:

4 G203V's driving the 4 motors (Gerald, please suggest the most standardized voltage, if there is )
PMDX-122 (7-12VDC or 6-9 VAC)
Proximity switches (12VDC)

I would like to finish with something close to it :D : http://www.mechmate.com/Forum/messages/17/3641.jpg

I´ll be working only weekends in this project because I have to run my business :cool: , please be patient, I will be posting information as soon as I generated it to build circuits, parts and development of manufacturing.

FOR NOW PLEASE LET ME KNOW ABOUT THE MOST IMPORTANT POINT TO CONSIDER FOR Ps CONFIGURATION, AND PLEASE, DON´T TRY TO BUILD THIS PS UNTIL WE HAVE FINISHED AND TESTED

Good machining :)

bradm Fri 10 September 2010 06:50

Hi Carl-

Actually, there are many of us that have built our own power supplies. We don't usually talk much about it because they are so simple: A Toroidal transformer, a bridge rectifier, and a capacitor. Add fuses on the input and output, and have a total of five parts with six connections between them. Linear power supplies are well understood and there are many designs and explanations around the web.

I suspect that it's just the convenience factor for a low price, and perhaps an unfamiliarity with purchasing electronic components that causes folks to buy the premade supplies. If you are comfortable with soldering you have many more choices.

Did you see this thread?

The two most important points to consider for your power supply are the voltage and the amperage. Unfortunately, we can't answer that question until you've chosen your motors. It is the specifications of the motors that lead to the voltage choice, and the voltage choice leads to the amperage choice.

Commonly chosen voltages with the G203V would range from about 35V to 65V, usually using the rule of thumb from Gecko: "Never use a power supply voltage greater than 32 times the square-root of the motor inductance expressed in milli-Henries (mH)." You want to be close to that number to get the best performance.

So, for example, if you have a motor with 4 mH inductance, sqrt(4) * 32 = 64V as
a recommended maximum, so a 60v supply would be reasonable.

For selecting motors, start here, and then give some consideration to belt drives

Red_boards Sun 12 September 2010 15:56

Carl,
The only qualification I had for building my own power supply was shocking myself repeatedly when I was young - now I'm more careful with electricity :o

I followed the calculations in the power supply threads and copied many posts to my own "personal build" word document so I could refer to them. As I worked through the calculations and read up on the internet on things I didn't understand (like what the capacitors and rectifier do), things became clearer.

Basically your motor choice determines much about your power supply. Choose motors and then you can plug numbers into the calculations.

I believe 300VA power supplies are adequate for most applications that use OM motors. I built around 600VA for my MotionKing motors because of their slightly higher impedance. The guys at the electronics supply helped me a lot in selecting matching toroid, capacitors and rectifier.

Red


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