Capacitive step-down transformer ...

[DeepCut]

OK i'm going with a single 1.05uf 2100VAC cap to replace his 100uf cap :

http://qvision.pwp.blueyonder.co.uk/cap.jpg

To replace his four 330uf caps i'm using one 35uf cap at 450V (electrolytic).

But i'm not sure about the connections in the oil cap, i think it may be two caps in one container but i can't find specs or pinouts.

Anyone know how the one in my picture is connected internally ?


Thanks,

Gary.

[FatBird]

It is just 1 cap in 1 container rated at 1 uF.

However, you might need more microfareds to get enough voltage.

You are right, it is good practice to just start small & work your way up.



.

[DeepCut]

Thanks FB.

Why does it have 2 pairs of terminals if it's one cap ?

Looking from above the polarity is like this :

          -     -
          +    +

But they short out unless you connect them diagonally, which is why i thought it may be two caps.


Thanks,

Gary.

[TinselKoala]

It's one cap. You should be able to see that the two spadelug terminals inside each black cylinder are in fact physically connected. The polarity markings and the multiple spade lugs are there so that the cap can be inserted into the microwave oven and hooked up to the correct wires easily and quickly.
These caps are not "polarized" in the same sense as electrolytic caps, so you don't have to worry about that. There will usually be some kind of marking to differentiate the outside/inside electrodes in the rolled-up paper/foil inside the can; this can be a small mark, like a dot or triangle,  near one of the terminals or can be indicated by a different color (black vs. brown for example) of the terminal insulators.

Even a 1 uF cap charged to a measly 12 volts can create a damaging arc.

Please be careful.

It's a good idea to store "big" caps with a shorting wire across the terminals; this one won't be dangerous but truly large caps can "self-charge" from static in the environment and give you quite a shock unless they are shorted in storage.

Also, please remember that the energy on a cap goes as the square of the voltage. If you charge that cap to 24 volts it will have 4 times the energy it has at 12 volts. When you start getting up into the kiloVolt range, that little 1 uF capacitor can be deadly.

[DeepCut]

Thanks again Tinsel, that explains a lot.

I'll be very careful


Gary.