This thread has got me thoroughly confused,(remember I'm not a lighting expert). What is the difference between a European H38 mercury lamp and an American H38 mercury lamp clear or coated? Or an H44 versus H44 lamp for that matter??
The ANSI rating is not used in Europe, so technically no H38 exist there at all...
But otherwise the MV lamps of same wattages have the same specs on both sides (all MVs are designed around 220V OCV induvtive ballast characteristics, so arc voltages start from 95V of a 50W, till 140V of the 400W), just to make the lamps compatible world wide (230V mains allows way more efficient and simpler series inductor as a ballast, if the lamp arc voltage is around half that mains so around 100V, while the 100V is not that far from the optimum, so lamps were made that way).
Just only few wattages reached wider spread in Europe (50, 80, 125, 250 and 400).
HPS are a different story, there the lamps are very (arc tube) temperature sensitive, so need more extensive match between lamp and ballast characteristics, not only in the OCV and nominal point to be stable.
Because the side effect benefot of a CWA (the suppression of mains fluctuation) was widely exploited in many US installations, there was a need to make the lamps sothey are stable on this gear.
On the other hand the series reactor common in Europe is rather limited in OCV, so needs lamps made more robust in that way.
These differences mean it was not possible to design a single lamp suitable for both gear type, so it made no sense to stick to common nominal arc voltage ratings.
Because the CWA cost the same and has the same losses regardless of the designed arc voltage, the US lamp arc voltages were set to really reach the maximum efficacy (except the low wattages, where the optimum was not that far away from 55V, so it became beneficial to design them with 55V arc for a simple series reactor), so that is why each wattage has so different nominal arc voltage.
The series choke ballast in Europe just yields all arc voltages in the 70..110V range.
So the US and European HPS lamps became very different, so you need to design the ballast from scratch when moving some lamp across the pond.
The US guys have the task a bit simpler, because of the pulse start MH gear is to big extend compatible with some EU HPS (50..250W range)
The probe MH were originally designed to run on an MV gear (that would make the US vs EU compatible), but it soon popped out the 220V OCV was not enough. That means the US ballasts had to be redesigned for higher OCV (no problem for MVs, just a bit higher ballast losses) and was practically a show stopper for this concept in Europe.
European answer for the OCV problems was to lower the arc voltage a bit (except 400W) so the 230 OCV suffices and move to a pulse start concept. Because the HPS were already pulse start and a bit lower arc voltage, these MHs were designed along the existing HPS ballasts.
That set a rating standard which became usable in the 120V area as well, so these tend to be the same.
Now how to match lamp vs ballast if they are not rated so? Following is
You have to look to basic properties:
Does the lamp needs a HV ignition pulse? Easy to adapt - disconnect/add an ignitor (to add, you need to find a superimposed type, which does not need any tap on the ballast)
What is the rated arc current? What deviation the lamp allows?
What is the required OCV? These last two are the crucial, but you may combine components to get what you need (e.g. connecting different fluorescent chokes in parallel to get the arc current).
Is there a restriction on the ballast output V-A loading characteristics? (Mainly important for saturated vapor lamps to make the setup stable and tolerant to parameter variations)
That means you may find already a few compatible combinations:
- 100W MV runs OK on a 70W pulse MH with ignitor deactivated
- 175W MV on 150W pulse MH or S56 HPS, again deactivated ignitor
- S56 HPS will run on 150W pulse MH
- 150W pulse MH may run on S56, may be less reliable to start; would need higher voltage ignitor
- 80W MV on 50W pulse MH deactivated ignitor
- 80W MV on two same phase F40 ballast outputs in parallel
And by going through different ballast characteristics you may find many more.
Anyway, these combinations are technically not using a matching ballasts, but designing the ballast from other components. That implies many of the certificates on the existing ballasts are void, so the contraption may become not compliant with the code because of the missing certificates.