I need some help with procurement of power sources?
I purchased TOROID 300VA 25V +25 V!
Me interested in whether to buy? PMDX 135, 50 volt, 20 Amp or PMDX 136, 50 volt, 10 Amp |
Sasa,
Since you bought a 300VA at 2x25V power source, then means your transformers maximum output current is : p=u*i i=p/u i=300VA/25v i=12Amp You would be better of with the PMDX-135 if you are looking into ways to save money and want to by the PMDX-136 then the consequences are: - More voltage ripple (more buzz so the speak) from the power supply at high currents. - Since it was designed for 10Amp, you might fire (as in real fire) something during long time high power usages. Ries |
Aha-ahaaa
Yes, the motive was saving money, .. Money, money, money Always Sunny In the rich man's world Aha-ahaaa All the things I could do .. www.youtube.com/watch?v=E5RSrNFj_is Excuse my stupidity to Thank you Ries |
Ries, I think that might be 300VA/50v=6A.
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Heath,
I was thinking that it was a power supply 50V out, 2x 25V, much like this configuration : http://www.antekinc.com/pdf/AN-3225.pdf Since his he mentioned the PMDX 135/136 at 50V you cannot run this transformer in series with the mentioned products, only parallel: sqrt(2)*25=35.4V (below 50V) giving it a maximum current of 12A Now, if Sasa is planning to run the transformer in series at 50V (sqrt82)*50=70Vdc (not below 50V) then he would still need the PMDX 135-8020 because that is actually a 80V/20A PMDX-135 If Sasa want's the run the transformer in parallel he needs to buy : PMDX 135 - 5020 or PMDX 135 - 8020 If Sasa want's the run the transformer in series he must buy : PMDX 135 - 8020 The PMDX 136 would not work because in series it's to much voltage for the PMDX 136, and in parallel it's to much current for the PMDX 136 Ries |
Ries,
Sorry for the confusion, I was fixated on the 50V part. Your last post sums it up nicely. :) |
now I'm a little confused
parallel or serial connection TOROID Transformer? variant of the capacitor + diode PMDX or 135( 80V or 50 V)? or I have no experience, and I have the possibility of all varieties .... what to choose? |
Saas,
that depends what stepper motors you are planning to use. Which stepper motors did you buy? Ries |
why spend $100+ on these boards when 1x bridge rectifier + enough capacitance (based on needs) will do the job as good?
http://img3.imageshack.us/img3/7272/bridgesf.jpg Stepper motors just need this, more is better, fancier but not really needed IMHO But, I understand if someone is not versed in soldering and want to go the off the shelf route :) Pablo |
Pablo,
http://img6.imageshack.us/img6/7671/kondezator.png http://img6.imageshack.us/img6/konde...png/1/w640.png Price two capacitors is about 106 $ + bridge rectifier about $ 5 Price PMDX 135 is (106$ - 50V) or (119 $ - 80V) I certainly buy PMDX 122, therefore, includes postage and PMDX 135th ..... , OK? Me interests what is better? Many thanks Ries , I'll try to get PK296AE-SG7.2 or MotionKing 34HS9801, now I would’t have to study anyway I believe Gerald_D! |
10000uF x80v caps are $16.60 here in Argentina in the 1st place I looked for them, Im sure I can trim an extra dollar or two if I look further. I would recomend to search for other providers, $53 seems to be pretty expensive. If thats your only choice, well then, I agree with you, the PMDX option seems a good one.
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@Sase,
Out of your power supply you wuill have : At 25Vac you will have a DC voltage of 25V*sqrt(2)=35Vdc At 50Vac you will have a DC voltage of 50V*sqrt(2)=70Vdc if my calculations are right, then with this power supply your only option is to buy Stepper PK296AE-SG7.2. Let's to the math: The 34HS9801 are 4.1mh unipolair, which makes maximum voltage for these stepper: sqrt(4.1)*32=64V, no good for your power supply because 35Vdc is not enough, 70Vdc is to much. The steppers PK296AE-SG7.2 are 1.5mh unipolair = sqrt(1.5)*32=39V This seems to be just nice for 35Vdc. Sase, I am not familiar with the PK296AE-SG7.2 stepper but I think people use them unipolar here so with your bought power supply that seems to be the only option. Ries |
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