Film-Tech Forum ARCHIVE: Can IREM N3-X75 be used for 2500W bulb

This is topic Can IREM N3-X75 be used for 2500W bulb in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Marin Zorica (Member # 1716) on 01-03-2009, 08:30 AM:

I have one X75 from irem, I hear the rectifier can be used for 85A (2500W) bulb without problems, only to change diodes and put some higher than are inside now, also I was think to add two fan at bot on so they can suck air inside to cool it better. Any experiences in doing this?

Posted by Louis Bornwasser (Member # 3063) on 01-03-2009, 09:27 AM:

I would probably agree to try this using 60 Hz current. HOWEVER, these run much hotter on 50 Hz than on 60 Hz. For that reason, I would be concerned about the health of the transformers themselves.

Remember the n3x75 is only rated at 1600 watts in Europe/2000 watts in the USA.

Bulb ratings:(Max)

70 amps 1600 watt

80 amps 2000 watt

95 amps 2500 watts

Of course you should actually figure the watts using the volts times amps formula. Louis

Posted by Marin Zorica (Member # 1716) on 01-03-2009, 09:40 AM:

It's actually rated as 4 KVA rectifier, so I think it would be possible, one thing more is that this is changeover booth, so it won't be operate as is for plex or whole show.

Posted by John Hawkinson (Member # 1135) on 01-03-2009, 10:19 AM:

I'd think you want a fan on top, not the bottom.
A fan on our two IREM P1-X80s makes a huge difference in its temperature, but it's probably being overdriven at 2 kW.

--jhawk

Posted by Richard Fowler (Member # 893) on 01-03-2009, 11:23 AM:

Even though the design of the N3-X75, in a vertical position, with disperse heat like a chimney; I have in many situations, cut holes on one of the side panels to mount (3) 220V 50Hz muffin fans cooling each transformer stack, with enough air flow to help the diode heatsink.....I would power them up via the 220V terminals on the Irem connection panels.

Posted by Mark Gulbrandsen (Member # 72) on 01-03-2009, 12:30 PM:

Yes, it should work ok especially considering that you more ethen likely have 50HZ 380 volt 3 phase which is what the windings on these older IREM's were usually wound for... Many of these rectifiers will barely light a lamp when run off of 208 volt three phase unless you install a booster circuit. I also second Richards idea of adding fans to the unit... they are way under heat sinked anyway.

Mark

Posted by Marin Zorica (Member # 1716) on 01-03-2009, 01:39 PM:

quote: Mark Gulbrandsen
Yes, it should work ok especially considering that you more ethen likely have 50HZ 380 volt 3 phase which is what the windings on these older IREM's were usually wound for... Many of these rectifiers will barely light a lamp when run off of 208 volt three phase unless you install a booster circuit. I also second Richards idea of adding fans to the unit... they are way under heat sinked anyway.

Yea it's 380V/50Hz and I run it on that voltage, normal for Europe [Wink]

But I was think also good thing would be to replace diodes with stronger one, they don't coast much but it will be safer.

Posted by Mark Gulbrandsen (Member # 72) on 01-03-2009, 02:25 PM:

Yes, Semikron makes a large but still size compatable diode that is actually shipped in all new IREM's. It's available in either english thread or metric. I highly reccomend that diode... SKR something er other I think... the exact number escapes me at the moment... I still also second the fans.

Edit: Check this one out... Big Honkin Semikron Diode

Mark