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Re: MMC practical apps.
Hi Doug, Philip,
> Original Poster: Doug Brunner <dabrunner-at-earthlink-dot-net>
>
> >From the information I've seen on some caps, MMCs can be a economical
> alternative to single units. The snubbers which were listed a while
>ago, and possibly some units I've found (which means there are
>probably many more like them) can be used in a single string, so you
>can build a good unit for about $30. This is for a cap that will
>probably be significantly more reliable than one than someone like
>me could build without making a LARGE investment in equipment.
Look for surplus or discontinued product lines. This is how I found my
62nF/1kVdc/330Vac caps for 16 cents a piece. Thatīs a price which
is hard to beat. Remember, it is not only the primary cost, which you
have to view (getting all the parts), but also the lifespan. If you
build a poly cap, that holds up for 10 hrs (pure runtime) for $30 and
build a MMC that lasts 100hrs for $100, then effectively, the MMC
is only 1/3 of the price of your rolled poly cap (you would need 10
rolled poly caps -at- 30 bucks each, making it a $300 grand total, to
get the same lifespan as one $100 MMC). This is kind of like
buying that cheap $30 angle grinder at the local hardware store
vs. the $80 good quality. Plus, once a rolled poly has gone south,
it is only a big (messy) paper weight. The MMC is repairable. If
you go for a different xformer, the MMC is versatile, the rolled
poly isnīt (etc, etc).
Doug, unless you are running a very small coil (<< 500VA), donīt
try using a single string. You will exceed the allowable current
(remember, the current in a string, has to go through EACH and
EVERY single cap) by a large margin. This will dramatically
shorten the capīs lifetime.
Coiler greets from germany,
Reinhard