1000w MH lamps - BT56 vs. BT37

[milemaker13]

Quick question..
I replaced two 1000 watt MH lamps. The one I removed is Sylvania M1000/u. M47/S. BT56 large envelope bulb.

The one I replaced it with is Philips M1000/u/BT37. M47/E. BT37 reduced envelope bulb.


I ordered 1000 w MH and these are what arrived.



Are these operationally the same in parking lot lighting?

 

[Electric-Light]

Quick question..
I replaced two 1000 watt MH lamps. The one I removed is Sylvania M1000/u. M47/S. BT56 large envelope bulb.

The one I replaced it with is Philips M1000/u/BT37. M47/E. BT37 reduced envelope bulb.


I ordered 1000 w MH and these are what arrived.



Are these operationally the same in parking lot lighting?

Put it side by side with the base against the same surface and compare the height of the arc tube. If the fuxture uses reflectors, the location of the arc needs to line up or it wouldn't make the correct beam pattern and waste the light

 

[milemaker13]

While the arc tube itself looks to be the same size, it is about 3" lower measuring how you described.

They seem to be doing OK this morning lighting up the parking lot, but that is compared to no lights at all. The fixture has a large glass lense and the entire lamp is visable. While not centered in the reflector, it is a flat sheet that curves around the lamp (like a big soda can cut open).

I think I will re-order the correct lamps. However, since these are already burning I won't be able to return them. Are these ok to leave in there until I get a chance to re-lamp again? Depending how the weather holds out this may be awhile (cold & sunny yesterday, but freezing rain today so I can't bring the lift out side without getting stuck).