Make my own Wire Wound Resistor

Thread Starter

Gdrumm

Joined Aug 29, 2008
684
I saw a better way to discharge a MWO high voltage capacitor that involves using a 150k ohm 25 watt wire wound resistor.

I have several smaller ceramic resistors, would one of those work? Could I put two or three of them in series to make one?

I used to have a wire wound resistor laying around, and now I can't find it.

Might I be able to make one for myself?

I also have a lot of electronic junk laying around, like PCs, Powerr Supplies, Stereo stuff, etc., what types of in home devices might have one that size?

Thanks,
Gary
 

cmartinez

Joined Jan 17, 2007
7,545
You could assemble a network of resistors in series and/or in parallel that would give you the required resistance and power.
 

MaxHeadRoom

Joined Jul 18, 2013
24,178
Several sources depending on what wattage and resistance, there are Electric furnace elements which can be tailored, also Nichrome wire can be had cheap in the internet, and S.S. Mig welding wire.
150k is fairly high for a DIY version!
Max.
 

cmartinez

Joined Jan 17, 2007
7,545
You may find this interesting.

Power rating: 450...1000 W
Dimensions: 126 x 300...126 x 600 mm
Resistance range: 2R0...1M0
Tolerance: ±5%... ±10%
 

ian field

Joined Oct 27, 2012
6,539
I saw a better way to discharge a MWO high voltage capacitor that involves using a 150k ohm 25 watt wire wound resistor.

I have several smaller ceramic resistors, would one of those work? Could I put two or three of them in series to make one?

I used to have a wire wound resistor laying around, and now I can't find it.

Might I be able to make one for myself?

I also have a lot of electronic junk laying around, like PCs, Powerr Supplies, Stereo stuff, etc., what types of in home devices might have one that size?

Thanks,
Gary
A while back I constructed a crude voltage breakdown tester that runs from the mains and has a decent sized pair of electrolytics in a voltage doubling bridge rectifier arrangement - the problem was how to make it safe between tests, by dumping the charge in the 2 electrolytics.

A shorting switch seemed obvious - until the first actuation blew the contacts away.

The replacement shorting switch was wired in series with a NTC inrush limiting thermistor, it starts off with a relatively high resistance at room temperature and doesn't sputter the switch contacts, as the charge in the capacitors send current through the NTC; it warms up and reduces to a lower resistance and discharges the capacitors rapidly to zero.
 

Kermit2

Joined Feb 5, 2010
4,162
a standard size resistor in the 5-10 Meg Ohm range could be attached permenantly and just be a 'bleed' resistor. a few min. after power off and the cap is discharged.
 
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