Film-Tech Forum ARCHIVE: Optimax II-S melted insulator plate!

This is topic Optimax II-S melted insulator plate! in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Tommie Evans (Member # 2674) on 10-08-2004, 01:54 AM:

Hi, I'm relatively new to the Strong Optimax II-S lamphouse.
Came in this morning to find the insulator plate (positive binding post) has atomised. Any suggestions on how this may have happened or how to prevent. All the connections were tight.
Specs: 4200W bulb running at 145amps 380/440v suffecient cooling.
The bulb still works from the switch underneath the lamphousing but the CNA200 automation 'lamphouse on/auto' switch is dead?

Posted by Leo Enticknap (Member # 534) on 10-08-2004, 02:59 AM:

Interesting... Darren came across a similar problem with a Cinemeccanica lamphouse at a student film society place he was servicing. The symptom was that the lamp either wouldn't strike at all or went out within a few minutes. The problem turned out to be a ceramic insulator plate against a bulkhead through which the anode lead passed. It wasn't totally gone, but had eroded to the point of allowing the lead to short against the bulkhead. I presume the cause was either heat damage or the insulator plate being a duff one to start with.

Posted by Stephen Furley (Member # 1277) on 10-08-2004, 04:57 AM:

quote: Tommie Evans
4200W bulb running at 145amps 380/440v

I don't think that's what you mean, is it? That would be 55.1/63.8 kW! 380/440 is the mains Voltage (phase to phase), not the lamp Voltage. At least I hope it is, otherwise I think you might well vaporise a few things! [Smile]

Posted by John Pytlak (Member # 331) on 10-08-2004, 05:58 AM:

Since the you say the connections were tight, and the wires themselves do not appear to be charred, I suspect that over time, the high voltage ignition had leaked across the insulating block (perhaps due to moisture or dirt), eventually burning it to the point that it began to conduct enough low voltage current to cause the severe damage you now see.

Any insulator for high voltage needs to be kept clean and moisture free, or there could be gradual breakdown, especially for insulators made of plastics. A ceramic insulator might have been a much better choice in this design.

Posted by Steve Kraus (Member # 476) on 10-08-2004, 03:39 PM:

Is there a way to run a line directly from ignitor to bulb without the need for an intermediate terminal?

Posted by Richard Fowler (Member # 893) on 10-08-2004, 03:50 PM:

This is common in older Optimax units: the U.V. from the bulb attacks the insulator and it will weaken. Heat also effects the insulator....nothing lasts forever [Wink]

unless they desire to spend a few more $$$ in components. The route around the 45 degree mirror requires the mid way connection point.

Posted by Tommie Evans (Member # 2674) on 10-09-2004, 05:55 AM:

quote:
I don't think that's what you mean, is it? That would be 55.1/63.8 kW! 380/440 is the mains Voltage (phase to phase), not the lamp Voltage. At least I hope it is, otherwise I think you might well vaporise a few things!

Sorry, that was the mains voltage - thanks for the advice the new part is on order [beer]