HID lamps means HPS and pulse-start MH lamps. But as the output current of this ballast is HF AC, it would cause acoustic resonances in the arctube that cause violent failure.

But then why does it run Probe Start MH with no problem?

Try to restrike a probe-start MH lamp with it, and you would see arcing inside the outer, as well as a bluish glow discharge in the arctube. This ballast isn't for probe-start MH lamps.

Try to restrike a probe-start MH lamp with it, and you would see arcing inside the outer, as well as a bluish glow discharge in the arctube. This ballast isn't for probe-start MH lamps.

Does it strike before the ignitor destroys the lamp when you first turn it on?

The HV pulses might distroy the lamp

The ballast would produces the HV pulses anyway.

Then why is the lamp OK when you first turn it on?

The main arc strikes, so it immediately limits the overvoltage. Allthough there is still overvoltage that the lamp is not built to handle, but it still survives it as long as it is cold and strikes immediately. Dont test your luck with it tho

The main arc strikes, so it immediately limits the overvoltage. Allthough there is still overvoltage that the lamp is not built to handle, but it still survives it as long as it is cold and strikes immediately. Dont test your luck with it tho

Why not connect an MOV?

There is no ballast that can used with both HPS lamps and probe-start MH lamps. Probe-start MH lamps needs 320V OCV for starting and different voltage/current than HPS lamps. HPS lamps also requires a HV pulse, if they aren't of the self-starting types. Probe-starts that restrikes after more than 20 mins, are usually these 1500W and 1650W for stadium lighting. I've seen a heavily blackened 1000W probe-start that restrike after 10 mins only on an autoregulator ballast, after a power interruption in the past.
Also, ballast for HPS lamps, are usually HX and not CWA, as HPS lamps voltage rises during life until they cycles, and this can allow CWA ballasts to run the lamps at dangerous high loadings. There are special non-cycling HPS lamps for CWA ballasts for mercury lamps, which don't suffering from voltage rise during life.

Actually, I think 1kw HPS ballasts can also operate halides. I once found a 1kw HPS/MH box at restore (was $120 so I didn't get it) but it had a switch that turned the ignitor on and off for HPS or MH.

Quote from: dor123 on July 29, 2016, 08:45:31 AM

There is no ballast that can used with both HPS lamps and probe-start MH lamps. Probe-start MH lamps needs 320V OCV for starting and different voltage/current than HPS lamps. HPS lamps also requires a HV pulse, if they aren't of the self-starting types. Probe-starts that restrikes after more than 20 mins, are usually these 1500W and 1650W for stadium lighting. I've seen a heavily blackened 1000W probe-start that restrike after 10 mins only on an autoregulator ballast, after a power interruption in the past.
Also, ballast for HPS lamps, are usually HX and not CWA, as HPS lamps voltage rises during life until they cycles, and this can allow CWA ballasts to run the lamps at dangerous high loadings. There are special non-cycling HPS lamps for CWA ballasts for mercury lamps, which don't suffering from voltage rise during life.

Actually, I think 1kw HPS ballasts can also operate halides. I once found a 1kw HPS/MH box at restore (was $120 so I didn't get it) but it had a switch that turned the ignitor on and off for HPS or MH.

And MH could mean MV?

But then why does it run Probe Start MH with no problem?

The fact it appaar to work does not mean there isn't any problem:
Normally when you start only cold lamps, the discharge within the lamp prevents the voltage from reaching any dangerous level (for the lamp), so in that way it may work long years.
Also you may be happy with even a hot lamp, when the arc get ignited within the arctube first, again preventiing any other damage.
But the things may change, once the lamp either ages a bit, or when it fails (even after a long life) and someone puts there another lamp, which won't happen to be that tolerant anymore (the difference could well be just manufacturing tolerances of exactly the same type).

So definitely it is not safe to let the ignitor operate into a probe start lamp not rated for that high voltage.

With magnetic ballast and a classical ignitor, I would say if it is not possible to remove the ignitor, so lets put there a stack of two series "240VAC" (with about 400V clamping voltage, so about 800V together) VDR's parallel to the lamp, so these will imit the ignition pulses to below 1kV, so what should these lamp survive.
But with an electronic ballast that could be tricky, as the electronic may use resonance to generate the HV with rather high power capability and so overheat the VDR's (with short pulses typical for the magnetic ballasts and even some electronic the energy has plenty of time to dissipate before the next pulse).
The problem with electronic is, there are just too many possibilities, how the ignition is performed. And each of them would need a different method to become eliminated...

Ballast says HID lamps, which for the applications it was made for, means HPS and MH. The HPS means it is a Pulse Start ballast, and therefore the mentioned MH is Pulse MH. No Probe MH, No Merc, No maybe. Just NO

The label is not accurate, as it is indeed not suitable for all HID lamps, but that is what you can expect from a label on a Chinese ballast. On some products it happens that they put the label to reassure you that it is ok for your grow lamp (to convince you to buy it), rather than to specify what types of lamps exactly it is for. The voltage ratings are there so the label dont look too empty (allthough they are probably correct)

MOVs are a "just in case" device, that have limited sinking capability and limited life resource. It will fail very soon, if not immediately in this application

Ballast says HID lamps, which for the applications it was made for, means HPS and MH. The HPS means it is a Pulse Start ballast, and therefore the mentioned MH is Pulse MH. No Probe MH, No Merc, No maybe. Just NO

The label is not accurate, as it is indeed not suitable for all HID lamps, but that is what you can expect from a label on a Chinese ballast. On some products it happens that they put the label to reassure you that it is ok for your grow lamp (to convince you to buy it), rather than to specify what types of lamps exactly it is for. The voltage ratings are there so the label dont look too empty (allthough they are probably correct)

MOVs are a "just in case" device, that have limited sinking capability and limited life resource. It will fail very soon, if not immediately in this application

So I have a ballast for CMH lamps. Awesome!

Even when there may be ways to overcome the HV pulses, I have to agree with Ash:
There is really NO safe way of operating a probe start lamp on a ballast designed for pulse start lamps.

So really the only option is to really deactivate the HV generating feature within the ballast. If that is not possible (even just because you haven't figured out how to do it), then sorry, no way to safely operate a probe start lamp on that ballast.


And indeed, CMH's should work fine...

Even when there may be ways to overcome the HV pulses, I have to agree with Ash:
There is really NO safe way of operating a probe start lamp on a ballast designed for pulse start lamps.

So really the only option is to really deactivate the HV generating feature within the ballast. If that is not possible (even just because you haven't figured out how to do it), then sorry, no way to safely operate a probe start lamp on that ballast.


And indeed, CMH's should work fine...

We have solved a mystery.
Wouldn't it be as simple as cutting the wires and covering them in a typical magnetic ballast?

In Magnetic yes. Or you could just remove it completely

There still may be issue of Probe and Pulse lamps of the same power having different arc Voltage/current ratings, but sometimes that difference is not too far off so might still work (allthough you have to be carefull, both for lamp and for overheating of the ballast). Especially Mercury lamps, those can be underpowered by quite a lot without adverse effects, in part because there are no Halides to form a corrosive liquid pool even when the lamp is not at full power