Film-Tech Forum ARCHIVE: What would be the difference between 70 amps through a 1.6 k and a 3k lamphouse?

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Posted by Cameron Glendinning (Member # 3516) on 01-10-2010, 09:47 PM:

What would be the difference between 70 amps through a 1.6 k cinemacanica x16 and a 3k Eprad lamphouse? Whould there be a noticable difference?

Posted by Demetris Thoupis (Member # 833) on 01-11-2010, 12:26 AM:

Depends on what mirror is being used. Glass mirrors are more light efficient (in theory at least). Cinemeccanica should have a standard metal mirror or a cold light metal mirror (cold light more light efficient).
Demetris

Posted by Cameron Glendinning (Member # 3516) on 01-11-2010, 12:40 AM:

I guess what I was asking is that 70 amps is as bright as 70 amps is no matter what bulb is used in theory, within there published range.

Thankyou for your reply Demetris [Smile]

Posted by Demetris Thoupis (Member # 833) on 01-11-2010, 02:17 AM:

Actually no! [Smile]

For example if using the Ushio High efficiency range, 70Amps are brighter than the standard UXL or CXL lamps. The same goes for the Osram although I would recomend Ushio. Ushio High efficiency can really blind you! [Smile]

Demetris

Posted by Mark Gulbrandsen (Member # 72) on 01-11-2010, 06:35 AM:

The 3 K Eprad is amazingly innefficient! The mirror in it can be replaced with a Super Lumex mirror by cuttinmg the hole in the dividing wall slightly larger to accomodate it. I've done many of these mods. Then you have a fairly decent lamphouse. Parts for the EPRAD are non-existant also...

Posted by Gordon McLeod (Member # 33) on 01-11-2010, 10:37 AM:

My experience with the universal eprad is that it was a very efficient lamphouse and we used a lot of them at one point for one circuit
As for parts most are off the shelf standard items

Posted by Mark Gulbrandsen (Member # 72) on 01-11-2010, 12:48 PM:

It WAS considered efficient in the late 1970's when it came out. The unfortunate thing is that the EPRAD doesn't even hold a candle to the Super Lumex. Installing a Super Lumex reflector which is a fairly easy thing to do and is still an off the shelf part as well... for the EPRAD will get you about 36 to 38% more light on the screen as well as alot flatter illumination field. The EPRAD igniitor was always reliable. Almost all of them in this area have been pulled from service in favor of much more efficient lamphouses so if you need any more of them just let me know.

Mark

Posted by Mike Croaro (Member # 3123) on 01-11-2010, 06:43 PM:

Hi Folks:

I think I know what Cameron is trying to say is:

Example - three different wattage lamps:

2000 60-84 amp range
2500 70-92 amp range
3000 60-110 amp range.

If you run each lamp at, lets say, 80 amps, will you have the same brightness, as the 2000 would run very high, the 2500 in the midrange, and the 3000 down low. Assume each lamp is the same brand and style.

Make sense?

Mike

Posted by Gordon McLeod (Member # 33) on 01-12-2010, 09:24 AM:

Actually you would not have as much light from a larger lamp run at a lower current due to the electrode design and arc concentration
what you do get is longer lamp life typically