I ran a couple of EMMC, Identical to Terry Fritz`s, in parallel to my
standard MMC this weekend, and one of them blew up in just a few
I had been troubled with internal archovers in my static gap, and fixed
them again, and set the individual gaplength at 30 mills, 0.75 mm. This
was "BAD", the safetygaps started flashing at only 7-8 gaps in service,
so I reset them to 24 mills., 0,6 mm, and that much better: I could now
use 16 gaps, and the streamers grew to 7`8" , 230 cm.
After this I plugged the 2 EMMC`s into service.
These were identical to Terry`s, but one had only 9 caps, the other had
After retuning, the first impression was that of the sound, following a
lower breakrate with the static gap, and a generally shorter
streamerlength, which was not what I had expected.
But I didn`t have much time to deal with this, because within less than
one ninute, the 9 capped string blew to pieces. All the epoxy around the
cap cracked, and fell off, one cap even caught fire.
My standard MMC was getting lukewarm, the center strings were 10 - 15
degrees C warmer than ambient.
The coil is now at a museum, and a lot of the guests came by to watch
the show, so the coil took a lot of service that day, and I pushed it to
the limits, untill I closed the doors to get some time on my own with
I know this is not definitive of much other than that where 20 caps in
series work, 9 in series may not, since I don`t have controll of the
exact voltages that the gaps fire at. There may also be an issue about
the current, since these two strings had to deal with 25% of the total
But I would like to post this as a caution against pushing the caps too
far, particularly when using PT`s, and pigs.
Details about my system can be seen at:
Hope this can be of some help still...