| hbarki |
Hello,
Have some questions regarding power supply caps:
I tried looking in Digikey catalog and found a 27000uF caps rated at either 50V or 63V.
1. Since we have a power supply output at 50V, should I be using more than 50V rating? (please let me know if I am wrong here).
2. Also, why most large capacitor (more than 27000uF) in the catalog has less than 50V rating?
3. Does it matter whether I am using a snap-in capacitor (soldered connection) or screw-in connection?
Any help appreciated, thanks |
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| MikeW |
Use more than 50 volts.
As the voltage and capacitance goes up so does the size of the cap.
It doesn't matter.
Try this link. It has some big caps. Look at the computer grade.
http://www.meci.com/ |
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| Panelhead |
| quote: | Originally posted by hbarki
Hello,
Have some questions regarding power supply caps:
I tried looking in Digikey catalog and found a 27000uF caps rated at either 50V or 63V.
1. Since we have a power supply output at 50V, should I be using more than 50V rating? (please let me know if I am wrong here).
2. Also, why most large capacitor (more than 27000uF) in the catalog has less than 50V rating?
3. Does it matter whether I am using a snap-in capacitor (soldered connection) or screw-in connection?
Any help appreciated, thanks |
The ouput of the raw supply is right at 50v when loaded. I feel more comfortable with the 63 volt caps. But this may not be an issue. A 50 volt rated cap should work fine at 50 volts.
George |
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| Nelson Pass |
Generally there is some margin built into the ratings. I
wouldn't be that concerned. |
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| vpharris |
| quote: | | 2. Also, why most large capacitor (more than 27000uF) in the catalog has less than 50V rating? |
Good question. I think two reasons. 1) Digikey doesn't deal much in "big hardware." Most of their parts relate to lower power electronics rather than high-power stuff. 2) As energy storage devices, capacitors get smaller in capacitance as the voltage goes up, reflecting the tendency for circuits of different types (I'm thinking tubes (high voltage) vs. solid state (low voltage)) to operate at similar power levels. Hence, your 27KuF cap at 50 volts might be a 6.8KuF cap at 200V for a tube circuit, which would run at correspondingly lower currents.
Does that make sense? Anybody else want to weigh in?
| quote: | | 3. Does it matter whether I am using a snap-in capacitor (soldered connection) or screw-in connection? |
Not at all, although some might have preferences. |
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