Xref: utzoo sci.electronics:3218 sci.physics:3729 rec.pets:3003 misc.wanted:2539 misc.consumers:5579
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From: learn@igloo.UUCP (william vajk)
Newsgroups: sci.electronics,sci.physics,rec.pets,misc.wanted,misc.consumers
Subject: Re: Need information about metal halide lights
Keywords: Metal halide lights
Message-ID: <770@igloo.UUCP>
Date: 4 Jul 88 23:00:21 GMT
References: <523@rbdc.UUCP> <5164@ihlpf.ATT.COM> <525@rbdc.UUCP>
Organization: igloo, Northbrook, IL
Lines: 26

In article <525@rbdc.UUCP> Andy Pitts writes:

> have had one person tell me that the lamps are interchangable in some ballasts
> which are labeled for use with either type of lamp.  A lot of old street lamps
> have ballasts with little or no labeling and I still would like to know
> if metal halides will work with these ballasts.  

The metal halide ballasts cost a lot more than the mercury vapor variety
because of design considerations. The price of those ballasts usually has
a lot to do with this sort of question which arises from time to time in
my business, electrical contracting.

To be brief, any ballast which might handle both sorts of lamps always
does so at the additional cost of shortened bulb life unless you have
paid a higher price for a ballast with multiple windings especially 
designed for multiple purposes. I've heard of such ballasts, but have
not found any in my collection of catalogs, and have never had occasion
to need one.

If you're technically proficient at design, you might attempt to create
a solid state ballast, otherwise you'll have to bite the bullet and
pay for the standard unit designed for use with metal halide lamps. I
further recommend that you acquire a complete unit with appropriate
shielding for RF considerations. These bulbs are of the arc variety.

Bill Vajk                                                  learn@igloo