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Posted By: rmiell dc lamps - 05/07/04 09:49 PM
This may be a dumb question, but I guess I have not thought about it before.

Can I put a regular incandescent lamp (120v, 100watts) on a 125vdc circuit?

I looked quickly through a couple of lamp catalogs, and did not find any DC rated lamps, the voltage rating were just listed as 120v, or 12v.


thanks

Rick Miell
Posted By: cpalm1 Re: dc lamps - 05/07/04 11:12 PM
yes, you can put a standard bulb on that circuit. however, you may wish to use "commercial" 130V bulbs rather than 120V bulbs since your circuit is 125V
Posted By: Bjarney Re: dc lamps - 05/08/04 04:34 AM
Incandescent lamps run fine on DC. One hitch though—most flush toggle switches are AC only. For tungsten-lamp switching, a DC {“T”} tungsten-rated switch is needed. They make plenty of racket during operation …none of that quiet AC-only stuff. They are listed as AC-DC General Use Snap Switches — UL Guide WJQR.
Posted By: frenchelectrican Re: dc lamps - 05/09/04 03:10 AM
Rick.

most indscent lamps can run on dc with out any troble but bear in mind that the dc verison will run slightly dimmer but not a whole alot but bulb life will be little longer too also.. i am not sure if you know this or not when bulb fail they do flash over pretty good btw just like 277 volts ac bulbs go out simuir idea so i dont know but i will guess you allready knew this or not put a over current device there to prevent serouis arc falut.

as far for switch use the genral usage snap switch .

merci , marc

p.s. i did work on one tug boat before it ran everything on dc before so i got pretty good idea how it react with it .
Posted By: pauluk Re: dc lamps - 05/09/04 08:51 AM
Filament lamps run on DC just fine, and if connected to a 125V DC supply you will obtain the same amount of illumination as on a 125V RMS AC supply.

Switches need to be the "quick-break" type for DC operation. The common "tumbler" switches used in this country when DC supplies were common employed a spring-action contact and opened and closed with a really noticeable clunk. The quiet AC-only switches will end up with burned contacts if used on DC.
Posted By: Joe Tedesco Re: dc lamps - 05/09/04 12:37 PM
Will these switches work too?

[Linked Image from joetedesco.com]
Posted By: rmiell Re: dc lamps - 05/10/04 05:56 PM
Ok, Thanks guys.

These lamps will be run thru a contactor, so switching will not cause a problem.

I knew you guys would give me a straight answer!!!!

Rick Miell
Posted By: Mean Gene Re: dc lamps - 05/11/04 03:57 PM
Joe, what were you doing at my mother's house? [Linked Image]

She still has a few of those and they work like brand new. Amazing, for being 80 years old now.
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