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#61164 - 01/18/06 10:28 AM Mercury Vapor bulbs  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
In some parking lot bulbs I'm replacing, will a 250 watt (M138) run in a 400 watt 277/480 volt mercury vapor fixture?


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#61165 - 01/18/06 11:04 AM Re: Mercury Vapor bulbs  
mshaw  Offline
Member
Joined: Jan 2006
Posts: 44
Fairborn, Oh, USA
I do not think so. I believe that the ballast and the lamp are matched so only a 400 watt lamp will work.


#61166 - 01/18/06 11:22 AM Re: Mercury Vapor bulbs  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
I'd advise against trying. While the bulb might fit in the socket, the igniter, capacitor, and ballast are all sized to the bulb. Having the wrong bulb in is likely to result in a very short life for the ballast.

While you're changing ballasts- why not upgrade to Metal Halide? MH bulbs do not decrese in brightness as they age, as mercury bulbs do, yet still give a clean white light.


#61167 - 01/18/06 11:31 AM Re: Mercury Vapor bulbs  
Old Town  Offline
Member
Joined: Nov 2005
Posts: 21
Dallas,TX USA
About 3 years ago I relamped about 10 70W med. base HPS lamps. I was out at the same place a couple of months ago and I had to replace a ballast. Much to my suprise the ballast was 100W. Lamp and ballast life seem to be uneffected by this mismatch. But I would not reccomend it.


[This message has been edited by Old Town (edited 01-18-2006).]


#61168 - 01/18/06 12:10 PM Re: Mercury Vapor bulbs  
CTwireman  Offline
Member
Joined: Feb 2002
Posts: 840
Connecticut, USA
Quote
MH bulbs do not decrese in brightness as they age, as mercury bulbs do, yet still give a clean white light.


That's not true at all. All HID lighting sources have declining lumen output as they age. HPS has the best lumem maintenance, followed by MH and then MV.

The basic probe start MH lamps have poor lumen maintenance, especially as they near the end of their rated life. However, pulse start and the newer ceramic metal halide systems have pretty well conquered this problem.

Peter


Peter

#61169 - 01/18/06 01:11 PM Re: Mercury Vapor bulbs  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
mshaw, I think you might be right. Also, both sockets are the larger Mogal base type.


The Golden Rule - "The man with the gold makes the rule"

#61170 - 01/18/06 01:15 PM Re: Mercury Vapor bulbs  
aldav53  Offline
Member
Joined: Aug 2001
Posts: 545
Chandler, AZ USA
Also, it says 480 volt on the fixture, did not measure it but it must be 277 volt. Don't think those are 480 from socket to center. Gotta be 277v.


The Golden Rule - "The man with the gold makes the rule"

#61171 - 01/18/06 03:08 PM Re: Mercury Vapor bulbs  
mxslick  Offline
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Joined: Oct 2004
Posts: 803
Atomic City, ID USA
The voltage referrs only to the fixture's input voltage, not the voltage seen by the lamp. IIRC merc vapors operate at around 80 volts once the arc is struck.

And the 250 watt bulb in the 400 watt fixture is an extremely bad idea. If you're lucky all that will happen is the lamp won't light. Otherwise you could easily have bulbs exploding or ballasts going down in flames.

Either get the right bulbs or get rebuild kits that will have the bulb, ballast and any other essentials.


Stupid should be painful.

#61172 - 01/18/06 05:24 PM Re: Mercury Vapor bulbs  
Rewired  Offline
Member
Joined: Jan 2006
Posts: 558
Hamilton, Ontario, Canada
If you are going to change everything you might as well go to HPS if colour is not an issue.. I believe the "lumens per watt" is greater for HPS than metal halide or old school mercury...
Also, double check your input voltage.. I once put a ballast in a fixture that was labelled " 230V". and had a " 115 / 230V" dual rated ballast.. too bad for me the input WAS 600V!
it looked spectacular for about 6 seconds when everything was turned on! [Linked Image]


#61173 - 01/18/06 08:16 PM Re: Mercury Vapor bulbs  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Aldav, I admit I was surprised the first time I encountered it, but there ARE ballasts out there that take 480v...two 'hots'...for their input voltage.
I was working on such a system just last week.


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