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Topic: What is a tungar bulb and its use?

Dave Ganoe
Expert Film Handler

Posts: 119
From: Point Marion, PA
Registered: Jun 99

posted 07-22-2002 01:17 PM

What is a tungar bulb and what is it used for? THanks.

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Jeff Taylor
Jedi Master Film Handler

Posts: 601
From: Chatham, NJ/East Hampton, NY
Registered: Apr 2000

posted 07-22-2002 01:35 PM

A tungar bulb is a vacuum tube type rectifier. I can't give you the actual specs, but have seen them used in old carbon arc setups that weren't large enough to require an mg set. Perhaps someone else can give a more detailed technical explanation.

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 07-22-2002 01:51 PM

Some links:
http://www.netcomuk.co.uk/~wwl/mercarc.html
http://www.tubecollector.org/list.php?L=-Z&M=Y&H=Rectifiers
http://www.dundeecoll.ac.uk/sections/cs/staff/al_radio/tungar.htm
http://www.du.edu/~etuttle/electron/elect27.htm#Diodes

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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Jeff Taylor
Jedi Master Film Handler

Posts: 601
From: Chatham, NJ/East Hampton, NY
Registered: Apr 2000

posted 07-22-2002 02:09 PM

TUNGsten / arGON= Tungar. Half wave, low voltage, low frequency rectifier. I can't say that it was preying on my mind, but it's nice to know! Thanks, John.

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 07-22-2002 06:27 PM

I have such a rectifier: http://steve.filmteknik.com/tungar.html

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John Anastasio
Master Film Handler

Posts: 325
From: Trenton, NJ, USA
Registered: Sep 2000

posted 07-22-2002 08:24 PM

They were just heavy-duty half-wave rectifiers. They had huge filaments and enormous tungsten plates to handle the high current and gave off a warm glow. I remember them being used in battery chargers in addition to small rectifiers for carbon arc lamphouses. You could put them in parallel to increase the current for larger lamphouses (up to a point...then you needed a motor/generator)

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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999

posted 07-22-2002 09:08 PM

We used to have a Tungar-tube exciter supply at the Clover Cinema back when it was a single screen...

-Aaron

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 07-22-2002 11:08 PM

The Cape Cinema (pics in the gallery) is using Strong tungar rectifiers to power the carbon-arc lamps. They switched from M-G sets at some point.

I've also seen tungar exciter supplies, which seems to be their more common use, although every place where I have worked has used the modern Kelmar or Smart exciter supplies....

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Kenneth Wuepper
Phenomenal Film Handler

Posts: 1026
From: Saginaw, MI, USA
Registered: Feb 2002

posted 07-23-2002 06:44 AM

OK, time for a 'historic' use of the Tungar bulb rectifier...

Used in the projction room end of the theatre where two bulbs provided full wave rectification for the 'field coils in the stage loudspeakers'.

Field coils were the pre-cursor to permanent magnets on the back of loudspeakers. Both the bass speakers and the horn drivers were powered by DC of the 12 to 20 volt type. When one Tungar burned out, you got a lot of "HUMMmmmmm" in the system. Even with the amplifiers off

When used to power the sound exciter lamps, the power supplies contained 2 Tungar bulbs and 20 or 30 oil filled capacitors of 10 microfarad capacity. That oil could leak out and the fumes were sickening.

That was over 50 years ago. Seems like yesterday.

KEN

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Jeff Taylor
Jedi Master Film Handler

Posts: 601
From: Chatham, NJ/East Hampton, NY
Registered: Apr 2000

posted 07-23-2002 07:43 AM

My only "hands on" with a tungar rectifier was in Jr. High School where we had an old carbon follow spot. Can't remember much about it almost 50 years later, but the thing was damn old even then. It used to crack me up that we had carbon arc for the spot but had to get by with an RCA 400 Jr. running 1200 w incandescent for film presentation. A porto arc projector sure would have been nice.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 07-23-2002 08:41 AM

Carbon-arc followspots are still pretty common, especially in sports arenas. Strong was making carbon-arc Super Troupers well into the 1970s; perhaps Pat can give us the exact date when they stopped. My college still had some (and a supply of carbons) at least as of a couple of years ago in their basketball arena, which was built in the mid-'70s.

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Matthew Bailey
Master Film Handler

Posts: 461
From: Port Arthur,TX
Registered: Sep 2000

posted 07-23-2002 11:06 AM

I'm not sure but I think I have some 1930's Audel's books & other
electrical books from those decades. Just a moment I'll run to my room & get them. Okay,I have a book from the 1930's by the Inernational Textbook Company in my lap titled RECTIFIERS, CONVERTERS,MOTOR APPLICATIONS. I am looking at Fig. 36 on page 53 of tungsten filament argon gas rectifier bulb & schematics involving it's use. I'll send the drawings that I will draw from it since I don't have a scanner.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 07-23-2002 08:38 PM

Tungar battery chargers were very common
In the 70's I ran a old theatre that had tungar tube rectifiers for the arcs and the excitor lamps

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Phil Hill
I love my cootie bug

Posts: 7595
From: Hollywood, CA USA
Registered: Mar 2000

posted 07-23-2002 09:19 PM

Tungar rectifiers were also used in electro-magnetic tool holders and "chucks" and in electro-plating like in copper and chrome.
They were used wherever AC needed to be converted to relatively low-voltage and very-high-current DC. They were replaced by selenium rectifier stacks and then with germanium and then of course with the silicon diode.

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