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 3 1 2 3 >
Topic Options
Rate This Topic
#205629 - 03/14/12 10:07 PM 100 W HPS fixture issue
Merlin Offline
Member
Registered: 01/27/04
Posts: 170
Loc: NW Indiana
I have a customer with a 100W HPS fixture on an outbuilding. The fixture is photoeye controlled. Almost everytime that a large load starts in the house (A/C, sewage ejector pump, ect.), the light shuts off and eventually comes back on.

The outbuilding and house are both on seperate loadcenters and feed from the same main panel at the meter. It appears to me that this is caused by voltage drop. Correct?? I even switch the fixture circuit to the opposite phase and it still does it. Could this be simply a photoeye problem, or utility service voltage drop???? Any suggestions?
Top
Work Gear for Electricians and the Trades
#205630 - 03/15/12 01:02 AM Re: 100 W HPS fixture issue [Re: Merlin]
sparkyinak Online   content
Member
Registered: 07/08/07
Posts: 1309
Loc: Alaska
Possibly the transformer is over loaded by other services. What's the incoming voltage at night? It tends to be a little lower in the evenings then the day
_________________________
"Live Awesome!" - Kevin Carosa
Top
#205632 - 03/15/12 06:34 AM Re: 100 W HPS fixture issue [Re: sparkyinak]
wire_twister Offline
Member
Registered: 07/25/07
Posts: 265
Loc: Georgia USA
+1 with sparky, check the voltage in the evening, and look at the size of the transformer, and its load. Call the POCO and ask for someone to come out and look.
_________________________
Jimmy

Life is tough, Life is tougher when you are stupid
Top
#205633 - 03/15/12 06:58 AM Re: 100 W HPS fixture issue [Re: Merlin]
Merlin Offline
Member
Registered: 01/27/04
Posts: 170
Loc: NW Indiana
This is in a rural area, only service on this transformer. voltage. Under start-up surge from A/C or sewage pump, I saw it drop to 112 for about 1/2 second. I switched the fixture to the "higher" phase (121) and it still dropped out under surge.
Top
#205634 - 03/15/12 07:33 AM Re: 100 W HPS fixture issue [Re: Merlin]
HotLine1 Offline


Member
Registered: 04/03/02
Posts: 6833
Loc: Brick, NJ USA
Merlin:
Did you ck the voltage at the fixture, or the source panel?

Sure sounds like a Vd issue...at the fixture.
_________________________
John
Top
#205635 - 03/15/12 07:37 AM Re: 100 W HPS fixture issue [Re: Merlin]
jdevlin Offline
Member
Registered: 08/07/02
Posts: 402
Loc: welland ontario canada
One side higher than the other would indicate possible loose neutral issue.
Top
#205636 - 03/15/12 09:21 AM Re: 100 W HPS fixture issue [Re: Merlin]
twh Offline
Member
Registered: 03/11/04
Posts: 899
Loc: Regina, Sask.
It's probably voltage drop, but try a new bulb to eliminate that before you spend a lot of money on it.
Top
#205637 - 03/15/12 09:51 AM Re: 100 W HPS fixture issue [Re: jdevlin]
sparkyinak Online   content
Member
Registered: 07/08/07
Posts: 1309
Loc: Alaska
Originally Posted By jdevlin
One side higher than the other would indicate possible loose neutral issue.


I agree with jdelvin that it could be a loose neutral. When A heavy load start on this service, does any lights on the premises get brighter?
_________________________
"Live Awesome!" - Kevin Carosa
Top
#205639 - 03/15/12 05:24 PM Re: 100 W HPS fixture issue [Re: Merlin]
wire_twister Offline
Member
Registered: 07/25/07
Posts: 265
Loc: Georgia USA
I agree with the possible loose neutral situation also. As far as the transformer, My house is the only load on a 15 KVA pole pig, it is about 60 feet from the pole to my meter, every time my 4.5 ton AC compressor starts there is a noticible flicker in the lights. Put this same load on a 10 KVA pot and it could pull down enough to turn the light out. What kind of meter did you use to measure the voltage when AC started? Most DVOMs are not fast enough to catch the dip, so it is likely the reading you got was on its way back up before your meter settled down. Just my 2 cents.
_________________________
Jimmy

Life is tough, Life is tougher when you are stupid
Top
#205640 - 03/15/12 07:32 PM Re: 100 W HPS fixture issue [Re: Merlin]
Tesla Offline
Member
Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
Rewire your High Pressure Sodium fixture across 230 VAC instead of 120 VAC.

I'm presuming it has a CWA ( Constant Wattage Autoformer ) with multiple taps.

I also suspect that the wire gauge used to feed it needs 240 VAC.

You've made no mention of the distance to the outbuilding.

Check if the photo-eye can be replaced with a 230 VAC sensor, too.

Every time its voltage pulls low it changes its logical state -- which is the primary cause for the HPS to cut out.



_________________________
Tesla
Top
Page 1 of 3 1 2 3 >

Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box

Recent Posts
Looking for older post
by sparkyinak
01/23/17 12:27 AM
License exam
by TRUE POWER
01/22/17 11:33 PM
Members: Non-Members: Did you know?
by Admin
01/22/17 02:34 PM
Safety at heights?
by HotLine1
01/21/17 08:51 PM
International Wire Colour Codes
by Texas_Ranger
01/21/17 03:29 PM

Who's Online
2 registered (Admin, sparkyinak), 82 Guests and 12 Spiders online.
Key: Admin, Global Mod, Mod
New in the Gallery:
Desk-mounted "power-board"
Top Posters
gfretwell 9066
Trumpy 8560
pauluk 7693
HotLine1 6833
sparky 5545
Member Spotlight
Tom
Tom
Member Since: 01/01/01
Posts: 1069

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