[Queensbury, New York]
MODEL I
Corona Grande Model I, discharge 3.75"
Corona Grande Model I, side view, battery compartment
Corona Grande Model I, rotary spark gap, 3 volt motor
MODEL II
(Photo courtesy of Harry Goldman)
Corona Grande Model II, "The Red Baron" coil, overall view
(Photo courtesy of Harry Goldman)
Corona Grande Model II, "The Red Baron" coil, side view
(Photo courtesy of Harry Goldman)
Corona Grande Model II, "The Red Baron" coil, solid 5" arcs!
Description of Harry's Corona Grande Model II coil:
Primary: 12 turns, 4" Diameter
Secondary: 16" on 1" PVC (#32 Cotton/Enamel)
Transformer: 7500/20 mA 100 Watts (measured)
Capacitance: .0025 uFd on each leg for total of .00125 uFd.
Interrupter: 2 Fixed gaps in series
Accessories: RF Chokes on each leg, safety gap to ground
Discharges: Solid 5" with lesser streams to 6"
MODEL III
(Photo courtesy of Harry Goldman)
Corona Grande Model III coil (overall shot)
(Photo courtesy of Harry Goldman)
Corona Grande Model III coil (close-up shot)
Description of Harry's Corona Grande Model III coil:
Primary: 12-13 turns
Secondary: 2" X 16" of #32 silk covered wire
Transformer: 9 kV @ 20 mA neon sign transformer
Gap: fixed series (4 gaps)
Capacitance: .003 uFd on each leg for total of .0015 uFd.
(Photo courtesy of Harry Goldman)
Same unit showing resulting 10" discharge at 180 VA
(Photo courtesy of Harry Goldman)
Double Corona Magnifier Jr.
(Photo courtesy of Harry Goldman)
Same unit displaying 7" discharge at 150 VA
Portable Tesla Coils
"Have TC Will Travel"
(Photo courtesy of Harry Goldman)
Portable Tesla coil mounted inside of an old spark gap diathermy machine case
Setting It Up
(Photo courtesy of Harry Goldman)
The secondary is attached by way of a 1/4-20 bolt. It can be inverted to change the coupling. Entire unit can be removed and fired out of the box.
(Photo courtesy of Harry Goldman)
Inside view of the portable Tesla Coil. Power source is 9kV / 30 mA NST. Hookup
wire good for only 5 kV but seems to hold up. Mica caps in parallel to give .006 uFd.
Chokes (2) have ferrite cores, safety gaps (2), air core tuning coil on farther leg.
Ready To Fire!
(Photo courtesy of Harry Goldman)
Although the collapsible ground rod is set at 8", the coil can produce a 12" point-to-point discharge
(Photo courtesy of Harry Goldman)
8" + arcs from Portable Tesla Coil project
Arcs will actually reach 12" if ground discharge were mounted further away at base of unit
(Photo courtesy of Harry Goldman)
Harry next to his low powered double ended Tesla coil. Produced 6-8" discharges.
(Circa 1950's, in case you couldn't tell)
Old Diathermy Converted To A Tesla Coil
(Photo courtesy of Harry Goldman)
Old Diathermy machine converted to a nice Tesla Coil
(Notice the nice, adjustable spark gap!)
(Photo courtesy of Harry Goldman)
Constructed from new, used, and fabricated parts. Present
arrangement (2/2008) produces 12" arcs. (16" to base)
(Photo courtesy of Harry Goldman)
Same unit shown with collector removed and base open for making inspection or adjustment. Base was originally used for an electronic timer. Motor is a vacuum cleaner motor, speed adjusted by a solid state control (similar to a light dimmer). Uses a removable computer cord for connection to 115 volt circuit. Note banana plug for connection to grounded sphere.
(Photo courtesy of Harry Goldman)
Ground sphere
11" sphere is a planter mounted on 3" PVC pipe. 31" tall as shown but can be varied up or down several inches. Banana plug for ground wire.
(Photo courtesy of Harry Goldman)
Vacuum Tube coil in early stages of construction
Description of Vacuum Tube coil (so far):
Plate & grid coils: 12-13 turns (commercially wound)
Secondary: #26 or #28 Cotton covered magnet wire on a 3" X 25" form
Tubes: Most likely 805's but, not as yet determined
Date of completion: unknown
(Photo courtesy of Harry Goldman)
Circa 1960's vacuum tube Tesla coil using two 701-A tubes. Fluorescent tubes would glow at 4-5' !
(Photo courtesy of Harry Goldman)
Same unit with the builder, Harry Goldman
(Photo courtesy of Harry Goldman)
Nikola Tesla's "Egg of Columbus" demonstration
(Photo courtesy of Harry Goldman)
Ruth Goldman experiencing Ed Wingate's "Cage of Death"! -- NY Teslathon (8/2002)
(Photo courtesy of Harry Goldman)
Traveling Arc (Jacob's Ladder*) project using a 1000 Watt bulb. Case is an old Hi-Pot tester
bought at a hamfest for $1.00. Powered by a 9 kV/30 mA NST. The tubes are Z15WB (actually, 15 Watt bulbs)
on a light dimmer to make them glow like the filament of a transmitting tube. They can also be made to alternate
at full glow (but I like the fake transmitting tube arrangement). Choke is to suppress parasitic oscillations (ha ha!).
The meter actually reads 5 kV (150 volts full scale). Large dial controls nothing (but looks impressive).
Insulators and discharge spheres are fakes.
(* This project originally appeared in the TCBA News, Vol. 14, #4, pg. 16 as "Dicta-Robotron II" by Louis Maury. The "Dicta-Robotron" was an idea Harry had after watching the Ed Wood movie, "Plan 9 From Outer Space". This device was also inspired by Hollywood's famous special effects master, Ken Strickfaden, of "Frankenstein" fame. "Louis Maury", one of Harry Goldman's pen names, was a combination of names taken from actor, Paul Muni's many films.)
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Copyright © 2008 -- Steve T. Cole
Last revised on Saturday, May 3, 2008