8mm Forum: HIGHER VOLTAGE?

This is topic HIGHER VOLTAGE? in forum 8mm Forum at 8mm Forum.

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Posted by Marty Pinkerman (Member # 1523) on April 06, 2009, 05:30 PM:

Does anyone know how to increase the line voltage (lamp)
from 12v to 24v
on an Elmo ST-180e? I want to use an elc lamp on this machine.

Posted by Steve Klare (Member # 12) on April 06, 2009, 06:30 PM:

Many people that do this kind of thing disconnect the lamp from the internal transformer and plumb in an external power supply.

Since incandescent lamps are pretty inefficient the question then becomes how well will the machine get rid of the better part of 150 Watts (or 2.5 times designed) extra heat in that same space? A friend of mine who did something similar added cooling air capacity too, but this was only for 150W in a 100W machine.

The lamp current would be 1.25 times normal.

The socket would need to be different too.

Posted by Paul Adsett (Member # 25) on April 06, 2009, 07:25 PM:

Steve has correctly stated the concerns in going to a 250 watt ELC lamp. First, there is no way that you can power a 250 watt lamp from the existing transformer in the projector - you will have to use an external 24 volt 250 watt transformer dedicated to just the lamp. Second, heat is a BIG problem. You will certainly need to hook up an external fan with sufficient air flow and air pressure capability to dissipate the 250 watts of heat. This will require very careful selection of the fan and the design of the fan ducting, and the fan must be electrically interlocked with the lamp power and the drive motor so that there is no possible way that the lamp can be powered up without the film running and the external fan running. It's all a real significant engineering job, fraught with the real possibility of destroying your projector if you don't have significant engineering know how. You might be better off forgetting it - and buying a GS1200.

Posted by Graham Ritchie (Member # 559) on April 06, 2009, 08:53 PM:

Marty
I also own a ST180 projector which uses the EFP 12V/100watt and a while ago did a side by side test on the GS1200 with its EJL 24V/200watt. That little ST180 was by far brighter so although we sometimes think fitting a higher wattage lamp will give a brighter picture this might not be the case, the same thing might happen with the ELC 250watt, as Steve and Paul have mentioned you stand to do a lot of damage to your projector with all that extra heat. The ST180 is a really nice projector and one thing I would recommend is replacing the 1.3 standard lens with a 1.1 this in itself will increase the light on the screen.

Graham.

Posted by Antonis Galanakis (Member # 1455) on April 07, 2009, 12:14 AM:

Have you try the 12v 100w Osram Xenophot? Less working hours but 20% more light.

Posted by Graham Sinden (Member # 431) on April 07, 2009, 07:09 AM:

Marty, You would be better off fitting a 2-blade shutter, coupled with the Xenophot bulb [Smile]

Graham S

Posted by Steve Klare (Member # 12) on April 07, 2009, 12:33 PM:

The Xenophot sounds interesting.

How many hours is it rated for?

Posted by Antonis Galanakis (Member # 1455) on April 07, 2009, 01:15 PM:

50 Hours.
Correct! Only 50 Hours. But who cares? It is 20% more light, only by just replacing the lamp! In 50 hours you can enjoy a lot of films. Buy two to have a spare. I did it. No engineering job at all!

Posted by Steve Klare (Member # 12) on April 07, 2009, 01:35 PM:

50 Hours is fine: the conventional EFP is also rated for 50 hours.

I'm due to stock up on lamps, maybe I'll grab some of these!

Posted by Mark Norton (Member # 165) on April 08, 2009, 01:34 PM:

CHC Had an ordinary looking ST180 for sale at the Tadley convention many years ago, but it had been modified to 250w lamp. I remember because I nearly bought it!

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