Re: Perfecting my final design...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Paul B. Brodie" <pbbrodie@xxxxxxxxxxxxx>

Christopher,
A while back, there was a post from a young guy in Israel. I think his name 
is Nir. He used a bank of microwave caps on his coil. Maybe he will see 
this and reply. If I remember correctly, he even had some pics on his web 
site. I'm sorry I can't remember any more than this. Does anyone else 
remember his posts about the coil he was building?

Where did you get those caps? I hate to tell you this but microwaves are 
there for the asking at appliance repair centers, at least they have been 
for me. In fact, thee owners I have dealt with have been very anxious to 
get rid of them They are easily disassembled and the transformers, HV 
diodes, and caps are almost always in good condition. Out of the 12 I have 
taken apart so far, I have only run across one bad cap. The repair guys 
tell me that the control boards are almost always the source of failure in 
microwave ovens and they cost too much to replace vs. buying a new 
microwave. So when this happens, people just leave their microwaves at the 
repair center and they are stuck with them. For some reason, junk dealers 
don't want them. Look on the 4HV forum and I'm sure you can find dozens of 
projects you can do with these caps. I feel sure that it won't be a total 
loss, by any means.

If you have any trouble with microwaves, locating them, identifying parts, 
or whatever, let me know and I'll try to help or point you in the right 
direction. Regards.
Paul
Think Positive

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, June 14, 2005 7:07 PM
Subject: Re: Perfecting my final design...

> Original poster: "Chris Rutherford" <chris1@xxxxxxxxxxxxxxxxxxx>
>
> I can't answer your question, but I'm slowly building/designing my first
> Tesla coil, unfortunately I *may* have just waited about $200 on some
> capacitors that may be useless.  I purchased 10 * 2500V 1.3uF microwave
> capacitors, they charge up nicely and produce a nice crack when discharged,
> except when thinking about their make up (liquid filled) and their 50Hz
> frequency rating, when I start to pulse them in the Khz range they may
> start to heat up due to losses etc.  Can anyone advise?  If they're no good
> as high voltage pulse capacitors would they be any good in a voltage
> multiplier circuit to drive a pulse capacitor? Or should I just use 4 * 4KV
> transformers with secondary in series??  Any ideas what I can do with 10 *
> 2500V 1.3uF 50Hz capacitors in relation to making a Tesla coil??
>
> Thanks
>
> Christopher
>
> ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Tuesday, June 14, 2005 7:02 PM
> Subject: Re: Perfecting my final design...
>
>
>>Original poster: "Adam R." <arabraxas@xxxxxxxxxxx>
>>
>>
>>I'd like to go with a large cap but I just expanded it! I am using the CD
>>caps (2000v .15uF) and have two strings of 15 for a .02uF cap bank
>>total...it does not look like I can easily get some more of those caps
>>(cheaply).
>>
>>Here are the results of the spread sheet, the inductance is much higher
>>than I thought.
>>
>>Diameter of tubing 0.25
>>separation of turns 0.25
>>Number of turns per spiral 10
>>Radius inner turn 4
>>Separation of spirals 2
>>length     TOTAL 2.5
>>n            TOTAL 100
>>L            TOTAL 3003.5
>>
>>Also, shouldn't the two spirals be wound in opposite directions so the
>>magnetic field matches?
>>
>>I'm worried working with the acrylic: I don't have special bits to drill
>>with it or saw it so I hope when drilling it won't crack and its only 1/4"
>>thick. To hold the copper tubing in I'm using PE cutting board strips. How
>>can I bolt the PE down? I'm guessing just extand 1/8" nylon bolts on the
>>strips.
>>
>>The distances btw the two coils will be adjustable so I can experiment
>>differing setups.
>>
>>Even just using two layers of 5 turns (6 or even 6.5"dia center) of .25"
>>Cu tubing spaced .25" apart (hopefully enough room to put 1/8" bolts?)
>>sounds like it'd work (with the .02uF cap). I'm just worried about using
>>thin bolts (1/8") but then that'd lower the risk of fracturing the
>>acrylic. (However, the center holes for the secondary are 1/4")....so
>>should I shoot for 5 turns? I might even be able to make a crappy mock
>>setup and test it with my L meter.
>>
>>
>
>
>