# Metal Halide Coming On and going Off



## 480sparky (Sep 20, 2007)

Loose connection somewhere in the circuit.


----------



## alpha3236 (May 30, 2010)

Faulty Photocell?


----------



## Wiredude (May 14, 2010)

First thought would be the ballast, but having 3 doing that in unison is beyond improbable.
Are all the poles on the same controls (photocell and/or timeclock)? Or are they split up?
If they are all on the same control I'm goin with 480's response, but if theyr'e on a seperate control, I'm thinking their light is tripping the controling photocell for that pole, or something like that.


----------



## Mr Rewire (Jan 15, 2011)

Do you have a single ballast controlling all three lights?


----------



## JohnR (Apr 12, 2010)

It is likely to be the lamp. It has a faulty weld, and when it heats up fully, cuts the power. Repeat. 
If they are not all the same time that is, still could be, if they are just close to the same time, look for loose pole or heads then.


----------



## Magnettica (Jan 23, 2007)

I'm going with the lamp is bad and should be replaced.


----------



## drsparky (Nov 13, 2008)

Voltage drop and current starvation. As the lights power up they rob power from the other lights and all shut down.


----------



## 480sparky (Sep 20, 2007)

Magnettica said:


> I'm going with the lamp is bad and should be replaced.



All 3 of them?


----------



## Magnettica (Jan 23, 2007)

480sparky said:


> All 3 of them?


Probably not if all three are coming on and going off at the same time.


----------



## The Lightman (Jan 9, 2010)

The photocell is wired backwards. Swap the red and black.
The other possibility is three capacitors that need to be replaced.
MH lamps do not normally cycle as HPS do unless the capacitor fails.


----------



## 220/221 (Sep 25, 2007)

I believe that pulse start lamps will cycle like HPS lamps when they are bad.

Troubleshooting 101 says:

1. Check power

2. Replace lamp

3. Replace ballast/cap and starter (PS or HPS)


----------



## OaklandElec (Jan 4, 2011)

Bad ballasts. Unless all three are going out at the exact same time, then you need to check the time clock, photocell etc. MH and HPS ballasts will cycle on and off as they heat/cool when the ballast goes. That's why you gotta sit there for 20 minutes after you fire them up to check for bad ones.


----------



## electronasized (Mar 4, 2011)

If the photocell or photocells are getting some of that light shed on em they might flash each other on and off ... is that pornographic?


----------



## Brechi98 (Jan 26, 2010)

I would say a loose connection or bad photocell. If it looses power for a split second, they won't start until the bulbs cool down, which would be around 5 mins. If not one of those, a large inrush to another load will drop the voltage enough to cause the bulbs to shut off until they cool.


----------



## miller_elex (Jan 25, 2008)

I like DRSparky's reply,

but I want to up the ante: DR's theory, but caused because the pole base shifted, snapped the pipe, and there's only a couple strands in the wire left completing the circuit, thereby drastically reducing the cmils.

Parking lot lites around here are always on the parking lot sub panel, which is downstream of a fat contactor. That contactor might be on a mechanical timer, might be on an astronomical timer, might have a photocell in there too, but I don't see photo-cells ontop of pole lights in decent size parking lots.


----------



## The Lightman (Jan 9, 2010)

miller_elex said:


> I don't see photo-cells ontop of pole lights in decent size parking lots.


You will be seeing more and more. Check out the Roam system. Twist lock photocells with a chip that communicate through satellite to control and report diagnostics. It's pretty unbelievable technology. They are going for municipalities with street lights first, then they'll be everywhere. 
http://www.roamservices.net/system.html
Ray Nagin installed a thousand of them.
ROAM works by allowing the equipped lights to receive information on neighboring lamps. If a street light is no longer working, the failure will register with nearby lights. This information is then transmitted to a network operations center. The Public Works Department and its contractor can access at any time through a secure internet web portal. 
Each working light can also send reports on its own status, 4 times daily or, on demand. These reports are possible through a combination of intelligent photocontrols, machine to machine communications (M2M), wireless communications, mobility technologies, and network management services.


----------



## miller_elex (Jan 25, 2008)

The Lightman said:


> ROAM works by allowing the equipped lights to receive information on neighboring lamps.


Is that a Zigby wireless mesh or an echelon chip network over powerline?


----------



## The Lightman (Jan 9, 2010)

Looks like it uses ZigBee Protocol. Click the link, it's pretty cool.


----------

