[Prev][Next][Index][Thread]

Another MMC cap candidate (UK)



I've been following the correspondence on multi-mini- caps.
And I was very impressed by the performance of Alex Crow's
coil at the UK teslathon.

What I have summarized is that the caps will not be killed by overvoltage
If the 1.414 * AC is these than the DC voltage rating of the cap.
So for my 8 KV AC transformer I need 8 of 1500V DC caps in series,
I'll probably use 8 by 8 in series / parallel.

They will also not be killed by over current is dV/dT is sufficent.

At 200kHz the voltage switches every 2.5uS, the voltage is 1500V max
1500 / 2.5 = 600 V/uS

Now looking through my R.S catalogue I see these caps.
It looks too good to be true - a 0.047uF capacitor, rated for an 8KV
transformer for under 30 quid ($45).

Are these caps suitable?

I'll probably buy 10 to start with and try them in parallel with my
existing
Cap.

Polypropylene Axial Caps

Manufactured by Arcotronics
A very low loss dielectric suitable for continuous use at high a.c.
voltages. 
It will withstand high voltage, fast rise time pulses
and has an excellent high frequency performance.
Film-foil poIypropylene capacitors protected by polyester wrap 
and epoxy end seals.

dv/dt = 1800V/uS

PF at 10KHz < 7*10,000

0.047uF Capacitance tolerance   20%
Rated voltage   1500V d.c. working (450V ac.)

5-45 -at- 46p, 50-95 -at- 41p, 100-495 -at- 35p  +VAT

40p is about 60cents

Question will I be able to use these caps or should I buy the
dearer double metalized types?

Have fun,

Alan Sharp