HMI lamp instead of Xenon in lamp house

[Jonathan Wood]

Hello ,

I was wondering whether anyone has ever made use of a HMI lamp in a 35mm lamphouse?
The lamp in question is the 575watt double ended one, very similar in shape and size to an equivalent Xenon.

The reason I am considering this is that I don’t have a spare single phase rectifier but I do have the ballast /power supply for the HMI lamp. I have also found a suitable ignitor. The lamp house is the old small Philips one that took I think a maximum 500watt xenon. Another reason is that HMI’s seem quite a bit cheaper and have a similar safe burn time . Also perhaps it’s possible to use the HMI ballast with a Xenon?

Any help or advice will be gratefully received.

[Gordon McLeod]

Is the ballast a square wave output as HMI run on AC and if a 60Hz sinewave type then you will have strobing

[Jonathan Wood]

Hi Gordon,

it’s this one
https://cvp.com/product/arri_l2.76184kh_1000hz_ballast
it’s not a magnetic type and is designed to synchronise with 50hz (uk) electronic shutters in pro video cameras to provide flicker free filming . I appreciate a mechanical 48hz shutter is a very different thing !

I believe that they operate broadly on the same principal as Xenon: HV ignition followed by low voltage high current DC to provide the arc? I could be wrong though .
thavks for your reply .
jon

[Randy Stankey]

I agree with Gordon about strobing but I was also thinking about color balance.

The HMI lamps that I have used in follow spots on stage seemed a little bit blue when photographed or recorded on video. If yours was designed for use in photography it might be okay or at least passable for your purposes.

If your lamp syncs at 50 Hz and your shutter runs at 48 Hz the difference between them is evenly divisible and you MIGHT get lucky enough to have run in phase but, depending on relative starting times they might not. When it comes down to it I think it would be, pretty much, a crap shoot.

Because, in your case, you aren’t doing mission critical work, you have the luxury to experiment. If you are feeling up to doing some tinkering you can try it and see what happens.

What’s the worst that could happen? Your colors will be a bit off and you get a flicker at two beats per second. Right?

If you are willing to tinker around with it, you might get a solution that’s close enough for horseshoes and hand grenades.

I’d say it’s up to you and whether you want to go by the book or use Yankee Engineering.

Like I said, you don’t have an auditorium full of customers depending on you and a boss looking over your shoulder to give you Hell if things don’t work perfectly. You get to decide how to do things.

[Gordon McLeod]

You could buy a used super lumex and switcher probably for that price

[Jonathan Wood]

Yes I know , but it was given to me ages ago and I’m hoping I can repurpose it

[Mark Gulbrandsen]

While the color temp is a way better choice than Incandescent, there will for sure be a flicker issue.

[Jonathan Wood]

Does the arc burn off AC then ?

[Gordon McLeod]

yes all hmi lamps are ac