The BigBaby Coil

Specs

• Power: Is, and for ever shall be, 12000Vac @ 60ma, 1 NST
  Unless, of course, I up that through modification to 12000Vac at 90ma.
  Input voltage controlled by a either a 10A 140V 60Hz variac, or the pictured 10A 220V 50Hz variac

  

• Arc Length:Now it's well over three feet. Not sure of the exact length, but adding a 120bps AC synchronous rotary spark gap was wondrous. When the second toroid was added, the arcs were nearly three feet. I hadn't had the chance to actually measure the max distance, seeing how the arcs were striking the ceiling of the basement.
  With each previous modification, the arc length did this: 18",25", 28", ~35". This will improve, very much so, -I hope-, when I eventually complete the rolled poly cap for it. 50" would be nice.
• RF Protection:Two 2.5" by 6" hand-wound air-core chokes, using 24 gauge wire on PVC, and a center-grounded saftey gap on the HV side. A 20 amp line filter is used on the 120Vac side. May eventually get rid of chokes, add bypass caps, ~800pf each, and power resistors to spoil any nasty 60Hz resonance.
• Spark Gap: An AC-syncronous rotary spark gap!! Most recently before that an RQ-style gap, complete with a muffin fan for cooling, ionized air removal, and ozone dispersion. Before that it was a nice gap with three adjustable sections, each gap being between a oversized (1.15") bolt head and a flat steel plate. The heads are very parallel to the arc plates, and this thing works nearly as well as the RQ-style gap. Before that it was 4 gaps made with steel 90-degree angle braces, but the fourth gap was slotted on it's support so as to be adjustable.
• Primary: Now is a large, 17 and 5/6 turn flat spiral using 1/4" coper tube on six 1/2" thick plexiglass supports, 2" high.
  This replaced a crappy 15-turn flat-spiral coil using stranded 14 gauge wire, stripped of its insulation, supported on 4 slotted wooden supports.
• Capacitors: I've broached the MMC barrier! While I may be the only person to ever use polyester, POLARIZED caps, it works! Only Salt-water for now, A Varied collection of 15 caps, the value being arrived at after I had someone be so nice to as to let me borow a capacitance/inductance meter!(thanks, Mr. M.) Nearly each one uses a different type of bottle... Originally set in one (for up to 8) or two (for up to 16) foil-lined plastic bases made to hold 8 plastic 2-liter soft drink containers. Now they all rest on a single piece of 1/16" aluminum, which in turn lays on a sheet of 1/2" plexiglass, which is usually supported off the floor by a plexiglass box.
  I'm in the process of gathering materials for a polyethylene dialectric oil-filled capacitor, which will probably be of the rolled type for my first attempt. I have a good deal of 4 mil polyethylene sheeting, which I plan on using in sections of ten layers, for 40 mills of dialectric. I also have a roll of aluminum flashing, but no insulating oil as of yet.
• Secondary: Wound on a 4.5"X18" section of PVC pipe, winding length = 16". This uses 24 gauge magnet wire, though when I first wound it I thought I was using 22 gauge.. ;) hey- the wire was free!
  Sealed with multiple coats of polyurethane.
  I want to replace it with a 20" bifiliar winding on thinwall 4" PVC.

  

• Terminal:Two toroids, one toriod formed from 4" flexible dryer hose, wrapped around 2 10" pie pans stuck bottom-to bottom, the center plate resting approx. 1" above the top winding. A second, formed from 6" Al dryer(?)ducting sits atop the first, about 24" dia. The wire completes a single loop on the top surface of the PVC, to conatct the toroid. In the past(before the second toriod) I kept two copper forms on top of the small toroid, each made from two copper plates (I mean like dinner ware)taped together to form a 1" thick copper disc.

This coil is the next step after building the baby coil, attempting to create arcs 4 times as long at a much better efficiency. Preliminary tests, using steel mixing bowls for a terminal, only 9000V @ 30ma, and a really bad spark gap yielded sparks just shy of 10".

Now, the coil is using higher-quality parts, and with only 12000V @ 60ma, it is tossing about 36" long streamers. Where will it end? I think with poly caps, a new secondary, a synchronous rotary gap, rf bypass caps, a new primary, and, I hope, with A LOT OF PUBLICITY ALONG THE WAY. :-)

An even more recent coil, of the Vacuum Tube type!

"...yes, and Jesse has still failed to produce coffee..." an opening statement on a video made around 4 a.m. ;-)

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email: electrophile@juno.com