[Home][2015 Index] Re: [TCML] Pulse Capacitors [Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Pulse Capacitors

Hi Dave,

It's a mixed bag with the 35xxx series as well, and many caps in this series are excellent for TC use. The Maxwell spec sheets for many in this series have NO stated PPS rating. For these, the Max. Dissipation Factor (MDF) or Design Life (# of charge discharge cycles, with 90% survival) can provide some useful hints as to their suitability for TC use. Mylar caps will have a higher factor (0.5% or higher) while polypropylene typically run 0.1 - 0.3% at 120 Hz. Design life for caps rated for high PPS will also have a long Design Life (millions or even billions of shots).

For example, the popular 35174 (0.06 uF at 40 kV) is rated for 100 PPS, has a an MDF of 0.3%, and a design life of 100 million shots - very suitable. A similarly packaged 35282 (0.06 uF at 50 kV) is rated for 1 PPS, has an MDF of 0.5%, and a shot life of only 100,000. Some caps in this series have shot lifetimes of only 30,000, and you never know how many are left on YOUR surplus cap.

Over the years I've accumulated a number of spec sheets, so I may be able to provide you with more information if you can provide me with series numbers. However, in all cases, a call to the GAEP capacitor engineers is really the best bet.

Best wishes,

Bert Hickman
Stoneridge Engineering, LLC
World's source for "Captured Lightning" Lichtenberg Figure sculptures,
magnetically "shrunken" coins, and scarce/out of print technical books

David Rieben wrote:
Hi Bert, What can you tell us about the "Tesla suitability" of the
GA/Maxwell 35xxx series pulse capacitors? I have seen these come up
on eBay from time to time but don't recall anyone bringing their use
up in this forum. David

On Tuesday, October 20, 2015 7:20 PM, Bert Hickman
<bert@xxxxxxxxxxxxxxxxxxxxx> wrote:

Hi Tim,

Most of Maxwell's 31xxx series caps are only rated for 1 Pulse Per
Second (PPS). A few exceptions models 31393, 31662, 31677, 31687,
31892, and 31981(all 100 PPS) and 31583(400 PPS). Maxwell's specs for
the Model 31190 0.08 uF 100 kV cap (currently listed on eBay) show
that the cap is indeed only rated for 1 PPS.

Although not explicitly stated, the polymer film dielectric used in
this cap may be Mylar (PET) and not (the more desirable)
Polypropylene. A call to General Atomics Energy Products (the current
owner of the old Maxwell line of products) would be strongly advised
before buying this capacitor. If the cap uses Mylar, it may work for
short run times in TC use, but you'll need to be very careful not to
overheat (and destroy) it. There may be better choices, such as an

Best wishes,


Tesla mailing list