I was thinking about making an HPMV arc tube thinner than the snandard sizes and replacing the argon buffer gas with krypton like it was done with 18, 36 and 58 W fluorescent lamps.
Would it be possible to make for example a 72 W high pressure mercury vapor lamp to replace 80 W ones like 36 W fluorescent tubes replaced 40 W ones?
The only reason I could think of why this wouldn't work is because the starting voltage would be higher so the lamps would need to be pulse start instead of probe start.
Or would krypton have no advantage over argon in high pressure discharges as opposed to low pressure discharges?

In regards to the energy saving mercury vapor lamps that have actually been made, I have not been able to find electrical specifications for the Westinghouse 300W energy saver mercury vapor lamps for North American 400W H33 mercury vapor ballasts as well as the Mitsubishi 375W energy saver mercury vapor lamps for Japanese 400W mercury vapor ballasts. However, I have been able to find electrical specifications for National/Panasonic’s energy saver mercury vapor lamps.

For your reference, here is what I have found out regarding National/Panasonic’s energy saver mercury vapor lamps for the Japanese market:

235W mercury vapor for replacing Japanese 250W mercury vapor:

140V 1.9A

Full power Japanese 250W mercury vapor is 130V 2.1A

280W mercury vapor for replacing Japanese 300W mercury vapor:

140V 2.2A

Full power Japanese 300W mercury vapor is 130V 2.5A

375W mercury vapor for replacing Japanese 400W mercury vapor:

145V 2.8A

Full power Japanese 400W mercury vapor is 130V 3.3A

660W mercury vapor for replacing Japanese 700W mercury vapor:

145V 5.0A

Full power Japanese 700W mercury vapor is 130V 5.9A

940W mercury vapor for replacing Japanese 1000W mercury vapor:

145V 7.0A

Full power Japanese 1000W mercury vapor is 130V 8.3A

I sourced the information from pages 1088-1095 of the 1992-1993 National Facilities and Outdoor Lighting catalog shown below:

https://esctlg.panasonic.biz/iportal/CatalogViewInterfaceStartUpAction.do?method=startUp&mode=PAGE&catalogCategoryId=&catalogId=792140000&pageGroupId=1&volumeID=PEWJ0001&keyword=&categoryID=&sortKey=&sortOrder=&designID=retireOut_sp&designConfirmFlg=


An interesting thing to note about the energy saving National/Panasonic mercury vapor lamps is that they have virtually the same published initial lumen outputs as their full power counterparts while Westinghouse’s 300W energy saver mercury vapor lamps have substantially lower initial lumen outputs compared to their full power counterparts.

I have sourced information about Westinghouse’s 300W energy saver mercury vapor lamps for 400W mercury vapor ballasts on pages 47 and 49 of the 1975 Westinghouse catalog shown below:

https://www.scribd.com/document/112839524/Westinghouse-1975-Large-Lamp-Catalog

More information can also be found in the following post:

https://www.lighting-gallery.net/gallery/displayimage.php?album=lastup&cat=14606&pos=3&pid=265870

How these reduced wattage MV lamps saves energy? Have they different buffer gas or something?

So far, I have not found any information on how they achieve energy saving. If one shows up on Yahoo Japan Auction or Mercari Japan, it would be nice for one of the collectors to use a proxy service to import one into their collection to study its spectrum throughout the warmup process to see if there are any additional buffer gases present.

Making a lamp that draws a different wattage is easy - just change the arc voltage by any means you see fit, be it the arc tube dimensions, fill pressure or fill gas composition

Lower voltage (vs. a standard lamp which arc voltage is not particularly high) will result in lower power draw of the lamp and increased ballast current. How low you can go would be limited by how much overload the ballast can be expected to withstand long term

High voltage within some range will reduce the current provided by the ballast, and reduce the power that way. However, this will very significantly narrow down the range of input voltage variation that the lamp can work with, resulting in a lamp that would go out and cycle for any minor dip in the line voltage, have unstable current that will vary a lot with small changes in line voltage, and probably stability issues over the lamp life. The ballast however will be running cooler with such lamp

The other question is did the lamp actually provide an efficacy upgrade ? Keep the light output of the full power lamp or at least not reduce the output as much as the input power, or just existed as a simple way to reduce the power and light together on existing gear

@Ash, From what I have read in the 1992-1993 National Catalog, it was mentioning that the energy saver mercury vapor lamps were somehow rated for the same lumen output as the lamps they were intended to replace.

The reality is that the so-called “Energy saver” mercury lamps are also “lumen savers”.  In fact, their efficacy is always worse than the lamps they replace, so if the power is reduced by 25%, the lumens drop by more than 25%.  Moreover, the ballast efficacy is also reduced, so the system efficacy is even worse.

Changing the arc tube fill from argon to krypton or xenon would have no significant difference.  During operation the rare gas filling is not ionised.  In HPS lamps we can improve arc tube efficacy by using higher pressures of higher molecular weight gases, because they reduce heat conduction losses to the arc tube wall.  But general lighting mercury lamps are not wall stabilised, there is much less heat loss to the wall, so the opportunity to improve efficacy by the same technique is absent. Possibly however the life could be extended.

@James, For some odd reason, I have been seeing that the 1992-1993 National Catalog claims that their energy saving mercury vapor lamps have the same lumens as the lamps they intend on replacing.

For example, I see that both the National 250W HF250X and 235W HF250X/235 lamps are rated for 12,700 initial lumens.

Additionally, I also see that the 300W HF300X and 280W HF300X/280 lamps are both rated at 15,800 lumens.

The 400W HF400X and 375W HF400X/375 lamps are both rated for an initial lumen output of 22,000 lumens.

The 700W HF700X and 660W HF700X/660 lamps are both rated for an initial lumen output of 41,000 lumens.

Lastly, the 1000W HF1000X and 940W HF1000X/940 lamps are both rated for an initial lumen output of 59,500 lumens.

I wonder why National decided to rate their energy saving mercury vapor lamps to have the same initial lumen output as the full power lamps they intend to replace. The information can be found on pages 1088 to 1095 of the 1992-1993 National Facilities and Outdoor Lighting Catalog.

See here:

https://esctlg.panasonic.biz/iportal/CatalogViewInterfaceStartUpAction.do?method=startUp&mode=PAGE&catalogCategoryId=&catalogId=792140000&pageGroupId=1&volumeID=PEWJ0001&keyword=&categoryID=&sortKey=&sortOrder=&designID=retireOut_sp&designConfirmFlg=

It seems to me that this catalog contains totally false information.

I am suspicious that they are just making use of the allowed tolerance of 10% on luminous flux claims.

It is possible though that they used a phosphor coating having higher efficacy than the common yttrium vanadate.  Same principle as the Philips HPL-4 which kept same power but higher lumens.

@James, If any one of us encounters one of those National energy saver mercury vapor lamps, one of us can probably take the time to possibly import one to conduct a spectral analysis and also measure its lumen output. These values would be compared to those of a National full wattage counterpart lamp.

That would be very interesting!  To measure the lumens would first require ageing for about 1 week, and even then no two lamps are ever the same or usually aligned with the nominal spec value.  But we could see if s different spectrum is present.  I will have to keep an eye open for these on the Japanese websites.

I am suspicious that they are just making use of the allowed tolerance of 10% on luminous flux claims.

It is possible though that they used a phosphor coating having higher efficacy than the common yttrium vanadate.  Same principle as the Philips HPL-4 which kept same power but higher lumens.

Interesting, i have a hpl-4 sitting around!