The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Page 1 of 2 1 2 >
Topic Options
Rate This Topic
#124700 - 12/01/06 05:27 AM Strange lightbulb
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Ever seen something as weird as this?.
Rated at 15W at 230V, the thing is, it has 3 pins, not two as your standard Bayonet cap bulb.
BTW here is the pic:



Sorry the other 2 pins are out of the frame, but this is not the first time I have seen lamps with this configuration.
Why would you have 3 pins on a lightbulb?.
Your guess is as good as mine so, go ahead!.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

Top
Tools for Electricians:
#124701 - 12/01/06 06:13 AM Re: Strange lightbulb
techie Offline
Member

Registered: 05/17/05
Posts: 240
Loc: palo alto, ca usa
Do you folks have the same 3-way lamps that we have over here? (dual filaments of differing wattages, which are run either individually or combined, for 3 different wattages. ie: 50/100/150)

Top
#124702 - 12/01/06 09:18 AM Re: Strange lightbulb
mamills Offline
Member

Registered: 11/30/01
Posts: 739
Loc: Wharton, Texas, USA
May be a silly response, but assuming that the other two pins look like the one shown, could they be for the purpose of keeping the bulb seated in the socket - a sort of bayonet device (push the bulb in and rotate it a short distance to the right or left?

Wild decorating on the outside, too...

The three way lamps we have in the USA start off with the same type of medium base screw shell, with the difference being the construction of the "button" in the insulating middle of the shell - a small button in the center, and a somewhat larger "ring" that encircles the space between the button and the shell. Shell is common to both filaments, with button as hot for one filament and the ring as hot for the other filament.

Mike (mamills)

[This message has been edited by mamills (edited 12-01-2006).]

Top
#124703 - 12/01/06 09:36 AM Re: Strange lightbulb
SvenNYC Offline
Member

Registered: 08/19/02
Posts: 1685
Loc: New York City
The pins on the sides of the cap are just to latch the bulb in the socket.

Electricity goes to the filament via two contacts (solder blobs, essentially) at the bottom. Similar to the center contact in a screw-base lamp.

The third peg on the cap was probably a way to thief-proof the bulb -- nobody would bother stealing it if they couldn't latch it into their socket at home. The theory would be similar to left-handed screw-in bulbs.

I can't explain the wacky paint job, though.

Top
#124704 - 12/01/06 01:14 PM Re: Strange lightbulb
Beachboy Offline
Member

Registered: 09/02/06
Posts: 26
Loc: Wamego, Kansas USA
As for the "wacky" paint job, I've seen very similar paint jobs on bulbs here in the USA. You can usually find them at Wal-Mart and places like that, usually 25 watt bulbs with wild paint decorations. They are sold as novelty "party" bulbs, just meant to be displayed in open fixtures, strictly for their decorative appeal.

Top
#124705 - 12/01/06 04:11 PM Re: Strange lightbulb
ShockMe77 Offline
Member

Registered: 06/11/05
Posts: 823
Loc: Rahway, New Jersey
Patridge Family anyone?

I'VE NEVER SEEN A bulb like that, no.

Top
#124706 - 12/01/06 04:26 PM Re: Strange lightbulb
Hemingray Offline
Member

Registered: 04/19/05
Posts: 195
Loc: Lehigh Acres, FL
SunBeam made bulbs like that here in the USA, generally rated 25W/120V. They were made in all sorts of wacky designs, Sold as "Art Bulbs" Commonly found in WAL-MART.
_________________________
Cliff

Top
#124707 - 12/01/06 05:24 PM Re: Strange lightbulb
allen476 Offline
Junior Member

Registered: 02/21/06
Posts: 7
Loc: Elmira,NY
I actually saw a bulb very close to this the other day. It was an orange color with the same type of size and base. When I asked what it was out of the customer replied that it was out of an electric fireplace that came from Europe. Also he said that the bulb made a flickering type of light.

Allen

Top
#124708 - 12/02/06 09:43 AM Re: Strange lightbulb
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Groovy color scheme..... If you weren't "down under" I'd think it came right out of the Haight-Ashbury district!

In line with Allen's comment, I've seen porcelain/brass BC lampholders in old electric heaters which have the three locating pins instead of the usual two. I don't recall ever seeing any bulbs in them though -- Possibly because they are no longer available?

Why a domestic electric heating appliance ever needed such an oddball configuration is anybody's guess. Plenty of other heaters had the regular BC lampholders and "Fireglow" or similar flickering amber/red bulbs for those are still obtainable.

Top
#124709 - 12/02/06 04:24 PM Re: Strange lightbulb
gideonr Offline
Member

Registered: 12/18/04
Posts: 152
Loc: Edinburgh, Scotland, UK
Three pin bayonets can be found on mercury vapour lamps:
http://www.lamptech.co.uk/Spec%20Sheets/Philips%20MLU300.htm

But this is more likely to be a fire glow lamp:
http://www.firstlightdirect.com/scp/Fire_Glow_Lamps/Special_Fire_Glow_Lamps.html


[This message has been edited by gideonr (edited 12-02-2006).]

Top
Page 1 of 2 1 2 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals