Hi Paul, Thanks - that info was a big help.BTDP is Maxwell's abbreviation for benzyltoluene/diphenylethane, a mixture of benzyltoluene (CAS 27776-01-8, 60%) and diphenylethane (CAS 612-00-0, 40%) by molecular weight. BTDP was a low-flammability low-viscosity alternative to PCB's that was introduced in the 1980's for high-voltage capacitors. It absorbs hydrogen gas (which is liberated during partial discharges/corona under oil) better than mineral oils, and it has a significantly higher static dielectric constant than mineral oil. Commercially-available formulations that have a similar mixture included Jarylec C100, and Nisseki SAS-40E, or SAS-60E.
I don't know these are readily available to private customers. So... if you can't get any of the above dielectric fluids, substitute mineral oil and hope for the best. :)
Could you please let us know the results of your repair. Other folks on the Pupman list may also have pulse caps with damaged cases.
And, good luck! Bert Paul McGlen wrote:
Hi Bert, Thanks for the response. This is the information that I have: It's a Maxwell (now General Atomic - model 37330, using their proprietary "oil". Impregnant: BTDP Regards Paul On Mon, Apr 1, 2019 at 10:04 PM Bert Hickman <bert@xxxxxxxxxxxxxxxxxxxxx> wrote:Hi Paul, If you can provide links to images of your capacitors, especially the face-plate, label, or stamped info, or if you can provide manufacturer info and model number, there is a possibility that we can identify the type of dielectric fluid. Was "Atomic Research" the manufacturer or perhaps the application they came from? As Jim Lux indicated, a large variety of capacitor dielectric fluids and blends have been used in HV capacitors over the last half century. Many of these fluids were proprietary and not readily available to a casual hobbyist and others (such as PCB's) are no longer available. And some benzine-based "aromatic" fluids were more volatile than others, so its possible that the capacitor rolls may have partially dried out. The easiest fix is to try adding mineral oil and resealing it. before resealing, drawing a partial vacuum for 24 hours or so may help to remove entrapped air inside the rolls if they've partially dried out. Finally, if the cap is packaged in a cylindrical container, remember to leave a small air bubble in the cap to provide room for expansion of the capacitor rolls especially if you plan to use the cap for Tesla Coil operation. The repaired cap should be usable, but you may need to derate its operating voltage... Bert Paul McGlen wrote:Hi All, I recently acquired some Atomic Research Pulse Capacitors. They are 50kV and 100nF, however, one of them was damaged and the oil has leaked out,soI need to replace this. Does anyone know what this oil is and where I can get it. If not can I replace it with high voltage transformer oil? Cheers. _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxxxxxx https://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxxxxxx https://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxxxxxx https://www.pupman.com/mailman/listinfo/tesla
_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxxxxxx https://www.pupman.com/mailman/listinfo/tesla