Lamp replacement on Mack bridge

[Richard]

I watched a part of the episode of Dirty Jobs showing the replacement of the flashing red lights at the top of the Macinack Bridge. Curious was when the new lamp went into it's socket it was immediately illuminated. Okay, so the base stays energized, what effect to the system when the lamp is removed from it's base? I have no idea of the wattage or voltage but I bet it's big.

 

[gismo]

I watched a part of the episode of Dirty Jobs showing the replacement of the flashing red lights at the top of the Macinack Bridge. Curious was when the new lamp went into it's socket it was immediately illuminated. Okay, so the base stays energized, what effect to the system when the lamp is removed from it's base? I have no idea of the wattage or voltage but I bet it's big.

I suspect the lamps are in the few hundred watt range but I don't see why there'd be any effect on the "system" (flasher?) unless it was designed to keep the filament warm between on periods. This is commonly done to reduce the initial surge that occurs when full voltage is applied to an incandescent lamp because the cold filament typically has 20 to 100 times less resistance than when it's lit.

Older flasher designs (it wouldn't surprise me that the flashers on the Mackinac bridge are as old as the bridge) likely didn't incorporate such a keep alive and relied on on an inductor and/or wire resistance to limit the surge to a level that wouldn't harm the flasher. If that's the case conneting the lamp "live" would have no ill effects.

 

[TangoWhiskey]

Okay, so the base stays energized, what effect to the system when the lamp is removed from it's base?

I can't help myself.

The correct question would be "watt effect" would it have?

 

[geneseib]

Typical lights on towers are 600 watts at 120 volts. Removing the bulb should not affect the system, because it's the same effect you'd get if a bulb burns out.

I watched a part of the episode of Dirty Jobs showing the replacement of the flashing red lights at the top of the Macinack Bridge. Curious was when the new lamp went into it's socket it was immediately illuminated. Okay, so the base stays energized, what effect to the system when the lamp is removed from it's base? I have no idea of the wattage or voltage but I bet it's big.

 

[Jack Spectre]

Typical lights on towers are 600 watts at 120 volts. Removing the bulb should not affect the system, because it's the same effect you'd get if a bulb burns out.

Correct. If they are wired in parallel you'll see no effect on the other bulbs. Some Xmas lights are wired in series and when one burns out, the circuit is broken.

 

[gismo]

Typical lights on towers are 600 watts at 120 volts. Removing the bulb should not affect the system, because it's the same effect you'd get if a bulb burns out.

Assuming the lamp was already "burned out", removing wouldn't do anything beyond exposing the socket's contacts and for that reason I speculated about the effects of inserting the replacement. And it seems like removing a working lamp while it was on would be kind hard for the fingers unless some sort of insulating gloves were used to protect the hands from the high temp.