HID ballasts have them, so do fluorescent, induction, and LPS ballasts have them?
The three main codes I know of a re H**, M**, and S**
If so, why don't they have codes?

LPS ballasts are HID & lamp must match ballast. Their codes are:

L69 - 18w
L70 - 35w
L71 - 55w
L72 - 90w
L73 - 135w
L74 - 180w

See also http://www.lighting-gallery.net/index.php?topic=117.0
Don't believe there are ANSI codes for fluorescent ballasts but the #, the watt & pin type are nearly always marked on their label.

I have a question: are the dual wattage 35/55 watt autotranny ballasts for 120v dual tapped for wattage or one size fits all like fluorescent chokes?

LPS ballasts are HID & lamp must match ballast. Their codes are:

L69 - 18w
L70 - 35w
L71 - 55w
L72 - 90w
L73 - 135w
L74 - 180w

See also http://www.lighting-gallery.net/index.php?topic=117.0
Don't believe there are ANSI codes for fluorescent ballasts but the #, the watt & pin type are nearly always marked on their label.

Thanks. I wonder why fluorescent ballasts don't have codes? Maybe because there are so many types and multi-lamp ballasts?

I have a question: are the dual wattage 35/55 watt autotranny ballasts for 120v dual tapped for wattage or one size fits all like fluorescent chokes?

I have no reply, except that I've settled this question myself by actually running an LPS 35/55 watt magnetic ballast.

There's only one pair of outputs for the lamp. I've run well both 35w or 55w lamps on the same socket. Similar to fluorescent ballasts, the choke will supply a certain max current to lamp. Looks like both these lamps require similar Amps to run nominally.

Quote from: Solanaceae on September 13, 2015, 03:20:49 PM

I have a question: are the dual wattage 35/55 watt autotranny ballasts for 120v dual tapped for wattage or one size fits all like fluorescent chokes?

I have no reply, except that I've settled this question myself by actually running an LPS 35/55 watt magnetic ballast.

There's only one pair of outputs for the lamp. I've run well both 35w or 55w lamps on the same socket. Similar to fluorescent ballasts, the choke will supply a certain max current to lamp. Looks like both these lamps require similar Amps to run nominally.

heh, I know that now since I have my own. Thanks though, George.

The induction ballasts do not have any codes, because there is no standardization at all, the lamp/couplers/ballast are completely proprietary (the Philips QL lamp works only with Philips QL coupler ans Philips QL ballast, same with other makers).

And the fluorescent ballast do have their codes - they are the in the form of the lamp designator (F32T8 means that ballast is intended for a F32T8 lamp, pretty easy...).

Using the coding system instead of the direct electrical specifications was introduced, because the discharges need quite too much parameters to be compatible to work, so it would be too tedious to match the ballast and lamp, while the number of lamp types in use was rather limited. So it was easier to define each lamp by it's code and have a detailed standard behind describing all the electrical parameters in details.

LED - ballast interface specification is so simple, so just the plain electrical parameters is used - the rated maximum current and the expected voltage drop on the LED modules, and an output current and the acceptable load voltage drop range for the ballast. As these are just three numbers, it is still easy to match and even allow to utilize the variability the LED's allow (driving the LED's below the maximum rating, series combination on a single ballast,...; all pretty straight forward math).
So on a LED you may find "0.7A/20..23V" - that means you may feed it by maximum 0.7A and with that you should expect voltage drop in the 20..23V range.
On a ballast you then find something like "0.5A/16..32V" - that means it feeds the LED by 0.5A and may accept LED's with forward voltage range not exceeding the 16..32V limits.
So these two above are compatible: 0.5A from the ballast is below the 0.7A LED limit, the 20..23V LED drop is within the 16..32V range accepted by the ballast...
Because the LED technology allows great variability of the actual LED current (a 0.7A rated LED module may be used just with 0.3A ballast, if the user just does not need the light output or wants better reliability), so no coding system or so was made.

LPS ballasts are HID & lamp must match ballast. Their codes are:

L69 - 18w
L70 - 35w
L71 - 55w
L72 - 90w
L73 - 135w
L74 - 180w

See also http://www.lighting-gallery.net/index.php?topic=117.0
Don't believe there are ANSI codes for fluorescent ballasts but the #, the watt & pin type are nearly always marked on their label.

Even if North American SOX lamps and ballasts have ANSI codes, SOX lamps are actually not high intensity discharge lamps and are more closely related to fluorescent lamps due to the fact that most high intensity discharge lamps have high pressure discharges while SOX lamps, all other low pressure sodium lamps, and fluorescent lamps have low pressure discharges.

Then, low intensity discharge lamp?

I don't know exactly know how the dual wattage SOX ballast work but I have one that's rated for 35/55w and another rated for 135/180w

I don't know exactly know how the dual wattage SOX ballast work but I have one that's rated for 35/55w and another rated for 135/180w

It is simple: Both listed wattages require tye same arc current, so the ballast just delivers that. Ballast is (in its operating range) a current source, so the current stays almost the same regardless of the load voltage.  The OCV is then designed according to the lamp with higher OCV need, so both are happy...

Thanks !

It is simple: Both listed wattages require tye same arc current, so the ballast just delivers that. Ballast is (in its operating range) a current source, so the current stays almost the same regardless of the load voltage.  The OCV is then designed according to the lamp with higher OCV need, so both are happy...

In some cases, whenever I use different lamps on the same ballast, I sometimes get different current readings based on the lamp that I use.

In some cases, whenever I use different lamps on the same ballast, I sometimes get different current readings based on the lamp that I use.

It depends how the ballasts are constructed.
The ballasts are current source, but not an ideal current source. So the current may somewhat depend on the actual load voltage, how much then depends on the exact design. The SOX is rather tolerant on that (no thermal instability,...), so ballast makers are quite free to optimize their designs the way they see fit.
Some (modern nonelectronic) may use low OCV (e.g. just a series choke on 230V mains and an ignitor) so yield quite strong load voltage dependence, but exhibit low losses and are not that expensive. Drawback is, these then can support only one wattage, as with the other wattage (with the same nominal current) the different arc voltage will cause the current to be off too much (more than the starndard allows)
Other (the older ones) may be designed with high OCV to be able to directly ignite the lamp without an ignitor and so have the output current very independent on the load voltage, so a single ballast may support multiple lamp wattages (they just have to be of the same rated current). The drawback is, these use to be heavier, more expensive and more lossy.

Either way, if the ballast is officially rated for multiple wattages, it means the manufacturer guarantees they took measures to make sure the parameters match any of the listed lamps. It is perfectly technically feasible, so some makers may chose to offer simplification of their customers maintenance logistics by offering one part/stock number supporting multiple wattage lanterns.
With electronic it is even feasible to make just a single ballast supporting both current ratings just by a wiring option, both technically, as well as economically (it would be slightly more expensive than the highest-wattage-only counterpart). It is really where the optimum lies (cheaper ballast construction vs cheaper logistic when having just one-ballast-suits-many products to deal with).

If only one lamp type is listed on the ballast, the manufacturer guarantees the compatibility only with that lamp type. It does not mean it can not run the other wattage as well, it is just not guaranteed (it may imply a restriction in allowed mains voltage tolerance, or the manufacturing spread may lead to a piece that wont fit the specs of the other wattage,...) and the eventual certificates the ballast bears are not covering its use with the other lamp, so become essentially invalid.