I ordered a Phillips 75W MV off of eBay(https://www.ebay.com/itm/163615449518) and I want to know what the best way to run it is. There are listings for H43 ballasts on ebay but they are all 277v. So what is the best cheap way to power this bulb as I only have access to 120v 60hz

Some may disapprove but I would just use a standard 70W M98 metal halide ballast (without the ignitor connected) and call it a day. MV is very tolerant to imperfect ballasting (or so I hear).

Looking at the specs for such a ballast, the OCV should be high enough. But the arc current is 880 MA, versus the 660 MA that a 75w MV is rated at. This probably isn't that bad, especially considering the bulb is a lifeguard bulb. Now call me stubborn but I'd rather have the arc current be a bit lower. I just don't want to take risks and/or lower the lifespan of the bulb.

MV seems to always have a higher running arc voltage that MH and that might help remedy the current issue to a certain extent. But, with this being a quality Lifeguard lamp, I would feel really bad treating it so poorly. I power my 100W MV lamp from a 100W MH ballast, but it is just a cheap GE one so I don't really feel bad, so I see where you are coming from.

I just looked at your gallery and saw that you have a 400W CWA HPS ballast. This ballast appears to be a multi-tap ballast from what I can see of the label. Make sure nothing else if connected to the ballast (no ignitor or lamp!), then wire up 120V to the COM and 120V wire as usual. Then, you will be able to use the COM and 277V wire to get 277V out of the transformer. Do not use the secondary winding for anything, just the primary. You can use this 277V output to power anything (400W or less), but in this case you can hook it up to a genuine 277V mercury vapor ballast for your Lifeguard lamp.

You can also do the same thing with the other voltage taps present (208 and 240) to get the other stupid difficult voltages you may need for things in the future. I used to use this method with a 400W MH ballast before I got my 3kVA converter transformer with all of the voltages I need.

Hope this helps!

You need a 50W (M110) metal halide ballast with the igniter removed to run your 75W mercury lamp. I’ve been running one like this for 5-6 years in dusk to midnight service and it still works nicely and has not significantly dimmed. Just make sure you disconnect the igniter.

@Multisubject is this ballast OK? https://www.ebay.com/itm/183860205506
Also, might sound dumb but MV can be run in any operating position without any issues right? I just don't want to damage this bulb.

Yes, the eBay one here is the official one. However, you need 277V mains to run it. You can use another HID ballast that is high wattage and multitap and use the 277V tap, or you can go the 50W MH ballast route.

Also, might sound dumb but MV can be run in any operating position without any issues right? I just don't want to damage this bulb.

Yes, that ballast will work just fine with the multi-tap trick.

Yes, all MV lamps are universal burn. Any position is fine. Unless the lamp specifically says otherwise, which I have never seen.

Just asking for clarity but with the multi tap ballast trick I disconnect everything from the secondary, connect the common from the wall to the common on the ballast and use it as the common for the output. Connect 120v mains to the 120v tap and use the 277v tap as an output. But do I, need to connect the common to the ballast in this setup? I'd assume so.

Another technique is to use a European 70W T8 preheat fluorescent choke ballast with a step up transformer with a 220-240V secondary as European 70W T8 preheat fluorescent choke ballasts also work well. Plus, North American multi tap HID ballasts with a 277V tap can also be used as a crude step up transformer for running the 277V 60Hz 75W H43 mercury vapor ballasts as well.

Additionally, here is a transformer that you can use to run the 277V 60Hz 75W H43 mercury vapor ballasts listed on eBay too:

https://www.ebay.com/itm/256804128066

They are not that expensive compared to other ones.

Here is one of the 277V 60Hz 75W H43 mercury vapor CWA ballasts listed on eBay that can be used with the transformer listed above:

https://www.ebay.com/itm/152820384554

Additionally, an 8 microfarad capacitor is also needed to be wired in series with the lamp:

https://www.ebay.com/itm/126344158326

I hope this parts list helps.

Additionally, If you are interested, here is a decent listing for a European 70W T8 preheat fluorescent choke ballast that should also run North American 75W H43 mercury vapor lamps perfectly:

https://www.ebay.com/itm/384500919180

It can also run okay on the 240V tap or 277V tap of North American multi tap HID ballasts as it is rated for 240V 50Hz.

Thanks for the part list, but it would be cheaper to buy this ballast https://www.ebay.com/itm/183860205506 and use my 400w CWA HPS ballast as a step up autotransformer to get the right voltage. It would be cheaper and this MV ballast is new and doesn't require a capacitor. Overall it would be cheaper. Also being a 400w ballast it should have a 400va power capacity when run like a transformer.

Sounds like a good idea. Those cylindrical ballasts are normally intended for post top fixtures.

Cool. One question though. The schematic for it shows the lamp with a capacitor symbol inside the circle representing the lamp, is this just representing the electrodes or does it need a capacitor? I wouldn't think so because it doesn't say anything about one on the label but I just want to be sure.

In that case, I do not think a capacitor is needed.

OK good. I will definitely buy this soon.