ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
AreMetal Ladders Ever OK For Electrical Work?
by gfretwell. 01/22/18 01:15 AM
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 5 guests, and 7 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
ballast question #2331
07/01/01 07:08 PM
07/01/01 07:08 PM
R
Redsy  Offline OP
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Can you operate a 250 watt HID lamp on a 400 watt ballast of the same type?

Work Gear for Electricians and the Trades
Re: ballast question #2332
07/01/01 08:39 PM
07/01/01 08:39 PM
S
silverbk  Offline
Member
Joined: Feb 2001
Posts: 60
No you cannot, hid ballasts are sized for their particular lamp. You also cannot run a mercury vapor lamp in a metal halide ballast of the same wattage. I have even had problems with using different manufacturers lamps in certain ballasts same wattage and type.

You can however change the ballast and the lamp to 250 watts with a retrofit kit. Both those sizes use a mogul base and are readily available.

Re: ballast question #2333
07/02/01 06:06 AM
07/02/01 06:06 AM
R
Redsy  Offline OP
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Silverbk,
This is just theoretical. I don't intend to try it. My thoughts were that the ballast coil would operate satisfactorily with a lighter, but not heavier load. Similar to a regular transformer. Does the ballast itself, or the lamp determine current flow?

Re: ballast question #2334
07/02/01 06:30 AM
07/02/01 06:30 AM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,264
Fullerton, CA USA
It's the ballast's job to regulate the current. (for a very good explanation go to Scott35's "choke transformer" in the Theory section of this site)
BTW, The Mercs do burn w/ a MH ballast, as evidenced by the fact that if you order a replacement ballast for the Merc you will receive a MH ballast. We've replaced them many times. It's not a "bright" idea, though. If you can replace the Merc w/ a MH lamp & ballast, you'll get a much more efficient light.

[This message has been edited by electure (edited 07-02-2001).]

Re: ballast question #2335
07/02/01 07:22 PM
07/02/01 07:22 PM
S
silverbk  Offline
Member
Joined: Feb 2001
Posts: 60
You are correct to some extent there are some MH and MV ballasts that are the same. In respects to a Mercury vapor in a MH ballast. But a Metal Halide will not work in an old Mercury vapor ballast, they require more voltage to start.

The newer MH lamps do not have a third starting electrode, making them and their ballasts incompatible with mercury vapor.

I have also had problems between brands, same wattage, ansi type, etc. Different lamp manufactuers use different materials for their arc tubes making them incompatible with other manufacturers balasts.

In my experience it is best to stick with kits when retrofitting hid fixtures, preferably prewired ones like Sola, takes out any guess work.

Re: ballast question #2336
07/02/01 09:05 PM
07/02/01 09:05 PM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,264
Fullerton, CA USA
Yes, but you said a merc lamp w/ a MH ballast earlier. [Linked Image]
Yes, I've experienced the same compatability problems as you have. We always replace the entire guts and lamp when we need to make a ballast change. It's not economical to return with a boom truck or a $300 a day rental boom lift to replace a capacitor or igniter in a fixture that you've previously repaired.

Re: ballast question #2337
07/03/01 09:26 PM
07/03/01 09:26 PM
S
spkjpr  Offline
Member
Joined: Dec 2000
Posts: 218
Sedalia,MO, USA
We just replaced the lamps at the factory I work at. We changed from mercury to sodium and Have been replacing ballasts on a regular basis even though the distributer said the ballast would be OK. Easy to say since he is not the one in the boom lift soaked in sweat replacing them.

Re: ballast question #2338
07/20/01 12:53 AM
07/20/01 12:53 AM
T
tajoch  Offline
Member
Joined: Feb 2001
Posts: 54
Quinlan texas, usa
Glad some one else mentioned that a merc lamp will light in a MH fixture....
My company is slowly replacing all the old merc fixtures with metal halide fixtures, but todate, they refuse to buy metal halide lamps....lol


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Theelectrikid
Theelectrikid
Levittown, PA
Posts: 810
Joined: April 2004
Show All Member Profiles 
Top Posters(30 Days)
Admin 21
sparky 16
Potseal 15
Popular Topics(Views)
243,592 Are you busy
180,388 Re: Forum
170,861 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.017s Queries: 14 (0.003s) Memory: 0.9912 MB (Peak: 1.1523 MB) Zlib enabled. Server Time: 2018-01-22 10:15:54 UTC