# Bleeder resistor help

I have a D C supply I need to determine what size, watts and resistance to use for a bleeder.
Capacitor is 7500vdc. 16uf.
15-20 sec bleed down

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13 kw is the value from what you give.

To select a suitable bleeder resistor, you can consider the relationship between the momentary voltage across the capacitor V t, the bleeder resistance R for discharge, the initial voltage V u. t is the momentary period and the total capacitor capacitance is C. Then, you can use this equation to estimate the required value of your bleeder:

• V t=๐u x ๐ (โ๐/๐น๐ช)
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Iโd point out that we have a calculator available for this precise purpose. Plugging your values into it and assuming a 60V โsafeโ voltage results in a suggestion for 280K resistance, with roughly 100W steady-state power dissipation, which recommends a resistor device rating of probably 150W+ in order to keep device temperatures reasonable. Observing any voltage limitations for the chosen resistor is also necessary.

I donโt see any single device in stock that meets those criteria, since the options thin out quite a bit at higher resistance values. (5) 50Kฮฉ, 50W devices in series could be a decent option though, yielding a bleed-down time in 18s territory. Note that resistors of this type typically need some heat sinking to achieve their nominal power rating.

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Thatโs what I was afraid of. I have a few 225w
50k and 100k. And 1 150k. Thank you for the info.