# HPS fixture



## shazam (Apr 16, 2007)

Guys are out on the job repairing lamps and ballast in some wall packs.

They have 120v at the base of the lamp but the lamp is not starting.

First thought was, wrong lamp guys. Nope it is the right lamp.

How does this happen? 120v but still won't illuminate??
Just when you think youv'e seen everything...........


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## Joe Momma (Jan 23, 2007)

I'm no expert, but I'm pretty sure you need upwards of 300V to get a sodium light to start.

Perhaps a bad starter in the fixture, but it's likely it's wrapped inside the transformer, so you'll have to replace the entire ballast.


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## Greg (Aug 1, 2007)

The cap (starter) could be external to the ballast. If the ballast is a multi-tap make sure they are hooked to the correct winding. Also make sure the cap and ballast are wired together correctly. I change alot of HPS, MH and Mercury Vapor lights in wall packs and parking lots. When one of the younger guys goes out and it doesn't work, nine times out of ten they wired the cap wrong. They other tenth is usually time clock and/or automation control.


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## John (Jan 22, 2007)

I will second the motion that it's most likely the Capacitor.

Ever hear of the 48/48/4 rule concerning electricity?


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## shazam (Apr 16, 2007)

Well, I haven't been out to see the fixture myself yet.

When I go I will keep the cap and wiring in mind. Thanks


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## Joe Momma (Jan 23, 2007)

So is this a guessing game John?

what's the 48/48/4 rule? 
I have the funny feeling it has to do with percentages?

I've heard of the 90/10 rule of troubleshooting
which says 10% of the system/parts cause 90% of the problems


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## itsunclebill (Jan 16, 2007)

:001_huh: High pressure sodium fixtures have both a capacitor and an igniter. The igniter operates a "tickler" circuit that makes the ballest produce voltage spikes up around 2KV to 5KV until the lamp ignites. If you have a good ear you can hear the noise the igniter produces in the ballest when you have a bad lamp or open circuit. The igniter is typically a small circuit board with plug-on terminals, a plastic frame that plugs in - will have 3 or 4 small components, or a small (half dollar size) tubular part with 3 wires(usually) The igniter is visably smaller than the capacitor.

The first test is try a new HPS lamp. If this fails try a mercury or metal halide of the same wattage, or a 200-300 watt incandescent with a mogal adapter. If the lamp comes on the igniter is bad. Don't do this any longer than necessary to prove a good ballest.

After a HPS lamp has been used a long time it winds up producing an internal gas pressure that requires more voltage than the ballest can supply to maintain the arc. This causes "cycling" where the lamp comes on, heats up, then goes back out. The older the lamp is and the longer it has been in this mode the faster this will happen. If you are doing maintenance on a group of lights turn them on for 15 or 20 minutes to see if any are beginning to cycle.

DO NOT put a meter across the socket connections if the fixture won't light. If the lamp is bad you will see the 2-5KV spikes across your meter.

It's been a while, but if I recall there is a point around 150 watts where the voltage changes from around 88 volts (up to 150 watt) to 100 volts (150 watt up) nominal on the lamp, and the 150 watt is made in both voltages - double check the info on the ballest AND the lamp in these.

Again, it's been a while but it seems to me that the max the ballest will supply to the lamp is around 108 volts, and you can predict lamp failure by checking the voltage supplied to it. Since it's been a while, you can verify the voltages I gave by installing a new lamp in a fixture and checking the voltage after an hour or so, then install a lamp that cycles and check the voltage continuously till the lamp goes off. Anything up in the volt or two of the cut off voltage is a candidate for replacement.

Finally, a yellow iodine color on the inside of the lamp is evidence of a leaking gas tube.:sweatdrop:


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## citysparky (Sep 8, 2007)

Well, I agree with unclebill. It's the starter 9 times out of ten. You can get a universal starter at your supply house.


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## Norcal (Mar 22, 2007)

Buy a ballast kit, less hassle and if another component fails where are the savings? Too lazy right now, but there are troubleshooting tips on the Advance Transformer website.


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## itsunclebill (Jan 16, 2007)

A bit of experience with HID lighting allows effective troubleshooting. Installing a ballest kit when an igniter is the only problem is sorta like stealing from the customer isn't it?


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## John (Jan 22, 2007)

Joe Momma said:


> So is this a guessing game John?
> 
> what's the 48/48/4 rule?
> I have the funny feeling it has to do with percentages?
> ...


*As applied to when changing the lamp in a light fixture.*

48% of the time the lamp will work.
48% of the time the Lamp will NOT work.
4% of the time the light fixture will go up in smoke  

*As applied to a service call to a residential customer*

48 % chance that the wiring was never to code.
48 % chance that the wiring is just old work methods that was to code at one time and just needs to be updated.
4% chance that the wiring IS really FUBAR.  

*As applied to replacing a 3 phase electric motor*

48% of the time, after the motor is hooked it will rotate in the correct direction.
48% of the time, after the motor is hooked it will NOT rotate in the correct direction.
4% of the time the motor will go up in a puff of smoke. 

The list goes on……….:jester: 
Add you own! :thumbsup:


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## Norcal (Mar 22, 2007)

itsunclebill said:


> A bit of experience with HID lighting allows effective troubleshooting. Installing a ballest kit when an igniter is the only problem is sorta like stealing from the customer isn't it?


You replace the igniter and then later fixture quits working ,then what do you tell the customer? Kit it and you have almost the equiv. of a brand new fixture.


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## Joe Momma (Jan 23, 2007)

Norcal said:


> You replace the igniter and then later fixture quits working ,then what do you tell the customer? Kit it and you have almost the equiv. of a brand new fixture.


If it aint broke, don't fix it.
Like Bill said, it's pretty much always the starter, so why replace the transformer under the notion that "it will fail one day". You could probably go through 5 capacitor's before xfmr fails.

I changed one last winter that was an all-in-one unit, the supply house 120 for the exact replacement, or 80 for the individual parts. I opted for the 80 to save the customer a few bucks. Installed it and as I was screwing in the bulb noticed it was Mercury Vapor lamp in a Sodium light.
Well so much for trying to save the customer money, lesson well learned for me anyhow.


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## itsunclebill (Jan 16, 2007)

:wacko: Where do you draw the line on CYA parts replacement? Do you replace motors when the start cap is the only problem? A bearing could seize next week. This isn't any different and is very straightforward.

Outside luminaires of any kind are in a pretty harsh environment. Close lightning strikes will often shorten the life of that brand new kit in the 
fixture to a few seconds or maybe a month or two. How do you deal with that?

If you educate your customers up front about the nature of HID lighting and build a trust you typically don't have to do much explaining to them. People who can get a good handle on the costs of lighting maintenance generally wind up with pretty loyal customers.

Do your homework. Megger the ballast to make sure those high voltage spikes don't have the opportunity to drill a hole that will eventually provide a low voltage short. Measure open circuit voltage to make sure the cap isn't bad or that windings haven't failed. Measure lamp voltage to do some lamp life prediction and verify cap status. Keep bad parts around so you can do hands on training with the help - a LOT of the issues with troubleshooting HPS fixtures are that people unfamiliar with them either don't believe what their test results tell them or misinterpret them.

My nickel's worth, anyway.


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