TWO-COLOR TELEVISION SYSTEMS, Part 6

Hawes Mechanical Television Archive

by James T. Hawes, AA9DT

Two-Color Television Systems, Part 7

Gould 3D: Camera & Monitor Formulas

• NOTICE. For more information on a topic, you may click the related footnote number. (Example: [3.])

Photo:
Marquee of old television service shop

(stock photo)

Propeller Motor & Horizontal Scanning
From the patent [1.]... Propeller Motor, rps= (frames / second) / Number of PE tubes (See the drawing, right. [2.] The motor is in the cutaway, just above the propeller.)
Then, rpm= [60 x (frames / second)] / Number of PE tubes

Worked Formulas for Cameras
*(stock photo)*	20 fps x 60 sec per minute= 1,200 rpm 1,200 / 2 cameras = 600 rpm pps= 20 Number of PEs= 2 rps= 20 / 2 = 10 rpm= (10 x 60)= 600

Monitor Formulas I [3.]

Provided Quanta
fps= 20 (given) Lines per frame= 240, vertical scan (given) Lines per camera drum revolution= 40 (given) Number of glow tubes= 2 (given) Glow tube rotation speed= 600 (given)	**Gould 3D monitor [4.]**
Worked Formulas for Monitor
Drum revolutions per 360-degree scan= [ 240 / 40 = 6] Camera drum rotation speed= (600 rpm x 6)= 3,600 rpm Frame Scan= 1,200 / 2 = 600 rpm ➔(Same as propeller speed of cameras) Motor 118 speed= 1800 rpm ➔(Opposite direction of tube rotation)

Monitor Formulas II

Drum slots = 60 (given)
Number of drum rotations per picture= 4
Drum governs LINE scan ➔(faster scan; vertical scanning)
Tube rotation governs FRAME scan ➔(slower scan)
Glow-tube speed, ignoring drum speed= 600 (given)
Drum speed, ignoring glow-tube rotation speed= (600 x 4)= 2,400
Drum speed with rotating glow tubes= (2,400-600) = 1,800 (CHECKS)

If Drum Slots Number 40...

Number of drum rotations/picture= 6, giving 240 lines
Drum must then attain speed of (6 x 60)= 3,600 rpm
With rotating glow tubes, the drum speed would then be
(3,600 - 600)= 3,000 rpm

♦ CAUTION: No 3,000-Hz sync motor is available in the U.S.A. Reason: Sync motor speed depends on the line power frequency. In the U.S.A, the line power frequency is 60 Hz. (The standard speed nearest to 3,000 Hz is 3,600 Hz.)

In the UK and Europe, 50-Hz power is standard, and 3,000-Hz sync motors are available. (See the table, Sync Motor Formulas, below.)

Number of Drum Slots. Apparently, motor availability is the reason that Gould chose to increase the number of monitor drum slots to 60.
With a 60-slot drum, Gould could reduce drum rotations to only four. He could then still obtain 240 lines: Meanwhile, revolving neon glow tubes (analogous to the propeller in the camera) would complete a revolution at 1,800 rpm.

Monitor Formulas III

Camera drum speed= 600 rpm (given)
Formula A:

240 lines / 60 slots

= 4 drum revolutions per frame
Formula B: (4 x 600)= 2,400, if neon tube rotation speed is zero
Formula C: (2,400- 600 neon tube rotation speed)= 1,800 (CHECKS)

Sync Motor Formulas
According to Audel Electric Motors: “The speed of a synchronous motor depends on the frequency of the current supplied to it and the number of poles in the motor. The equation for speed is revolutions per minute= frequency x 60 / number of pairs of poles ” [5.], [6.] The formulas below apply to Gould 3D, and derive from the formula above...
Formula	Example
•60-Hz countries: Max rpm= 60² •50-Hz countries: Max rpm= (50 x 60)	60²= 3,600 (50 x 60)= 3,000
•rpm= Max rpm / No. of pole pairs	3,600 / 3 = 1,200 rpm
•No. of pole pairs= Max rpm / (60 x fps)	3,600 / (60 x 20) = 3 pole pairs
•fps= Max rpm / (60 x No. of pole pairs)	3,600 / (3,600 / (60 x 3)) = 20 fps

About: Gould's Lost Creations
Gould was an amazingly resourceful engineer. What else did he invent? For years, the answer to this question has been lost in the U.S. patent office in Washington, D.C. After a thorough investigation, our author has unearthed more of Gould's fascinating creations. Don't miss The Lost Creations of Leslie Gould!

Footnotes

1. Leslie A. Gould, Television Apparatus and Method [3D patent], U.S. Patent 2,058,681 filed June 16, 1932, and issued October 27, 1936, 3, Column 1, Line 20. (Referring to Figure 3.) Assignee: Radio Inventions Inc.
https://patents.google.com/patent/US2058681A/en?oq=U.S.+patent+2%2c058%2c681
•Re: Math formulas that relate to Gould's camera mechanism, including variations. Applies to Motor 112, which sets horizontal scanning speed in RPS (revolutions per second).

2. N.A., “Television Projected in Three Dimensions,” Television News, May-June 1931, 132. •Re: (Graphic) Propeller motor for Gould 3D, two-color television. Television News article includes illustrations & brief description. Author has retouched & slightly altered propeller graphic.

3. Ibid., [3D patent], 3, Column 2, Line 45.
https://patents.google.com/patent/US2058681A/en?oq=U.S.+patent+2%2c058%2c681
•Re: Math formulas & commentary about Gould's 3D monitor.

4. Ibid., [3D patent], Figure 4.
https://patents.google.com/patent/US2058681A/en?oq=U.S.+patent+2%2c058%2c681
•Re: Figure 4 of Gould's 3D television patent: Monitor diagram.

5. Rex Miller & Mark Richard Miller, Audel^™ Electric Motors: All New 6th Edition (Indianapolis, IN: Wiley Publishing, Inc., 2004), 40. •Re: Synchronous motor formulas for speed & number of pole pairs. (Discussion continues on pp. 41 & 176.)

6. Austin Hughes & Richard Drury, Electric Motors and Drives: Fundamentals, Types and Applications, 5th ed. (Oxford, UK: Newnes div. of Elsevier, 2019), 165 & 309. •Re: Sync motor formulas for speed & number of pole pairs. Gives formula in slightly different form than in Audels book above. (Refers to poles, instead of pole pairs. Formula gives same answer, either way.) Hughes & Drury formula...

N_S=
120f / p

where...
N_S is synchronous speed
f is supply frequency
p is pole-number of winding (Must be even integer!)