unnecessary emergency light

[jimingram]

In our new state of the art school I noticed that the exterior recessed luminaires have a second lamp in the them. The factory rep. told me that this second halogen lamp is an emergency lamp. The luminaires are 70 watt MH with a 120/277 volt ballast. They operate at 277 volts. The second emergency halogen lamp has a transformer connected to the secondary of the MH ballast. It operates at 120 volt. When the 70 watt MH is on, the halogen is on. Normal operation for these luminaires is dusk to dawn.

These luminaires also have backup power. Backup power is provided by a Liebert battery pack. There are two circuits to these luminares, each coming from a different panelboard. One circuit is from a normal power panelboard and the other is from an emergency panelboard. The two circuits connect to a relay in a lighting control panel. From this relay one conductor goes to the luminaire. This one conductor has either normal or back up power on it. Also of interest, I have observed that the battery power is capable of operating the 70 watt MH lamps.

It seems to me that the second emergency lamp is unnecessary and wasteful. The factory rep. said that these emergency lamps were only suposed to come on with the back up power. This is not so. If there's power on the one conductor, normal or emergency, both lamps are on. Why not remove the emergency lamp? The MH lamp will operate on emergency power.

Your thoughts please.

Jim

 

[rblack]

local 58 wireman

local 58 wireman

when there is a power interruption, the metal halide lamp fixture has to cool down before it will relight. this is not acceptable for en emergency light. but the halogen light will relight immediately so no one is in the dark. hope this helps.

 

[maghazadeh]

when there is a power interruption, the metal halide lamp fixture has to cool down before it will relight. this is not acceptable for en emergency light. but the halogen light will relight immediately so no one is in the dark. hope this helps.

I agree with rblack, also the em halogen lamp should only be lid when normal power is intrupted.

 

[roger]

The factory rep is right, the fixtures are wired incorrectly if the restrike lamp is burning continuously.

Roger

 

[iwire]

Why not remove the emergency lamp?

Please do not do that it is required as others have mentioned but normally there is a small controller included in the fixture that only operates the re-strike lamp when needed. It should not be on full time.

 

[Strathead]

Normal sequence of operation:

There is a time delay relay that closes on denergizing, remaining closed upon power application and then times out and opens after a set time. This relay, in my experience has a 120 volt coil and is wired to the 120 volt hot and nuetral of the ballast. If the fixture is wired to 120 it is in parallel with the ballast feed, if any other voltage it gets power via the inductive properties of the transformer. That way you don't need a different relay coil for each voltage.

 

[ken44]

We also have this type of fixture in one of our 15 parking garages (soon to be retrofitted to LED) and while the emergency lights work properly, BEWARE around these fixtures as I have found that you must be careful because the lamps will burst into hot molten glass which is why they are encased by a glass cover. Handle with care and dont operate without the cover in place.