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 -- Bert Hickman Stoneridge Engineering, LLC http://www.capturedlightning.com *********************************************************************** 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 MMC. Best wishes, Bert
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