120v 400w Metal Hallide HID Light running on 100v line?

[hippyskitz]

So I'm trying to run this 400w HID light in Japan (which has 100v output) but the ballast for the light is rated for 120v-240v.

I want to know if the light will still operate, albeit at lower output, or if there is risk of damaging the light.

 

[MJPD29]

Not in line with what the manufacturer has stated, so regardless of whether it will work or not I would not do It.

 

[Lucien Nunes]

As the 'ballast' accepts a range of voltages, I assume it is an electronic 'lamp power supply', i.e. an SMPSU rather than a wirewound ballast. This is an important distinction. An LPSU runs at constant power and will normally drive the lamp correctly at full power or not at all. The lamp would not be underrun, as it would be with a 120V wirewound ballast. However, when the supply voltage is too low, the input current will be increased and at some voltage, the unit will shut down to protect itself. Or it should; there is a possibility of blowing its internal fuse in the meantime.

Most 120V equipment will work in Japan so long as the voltage is actually around 100V and not affected too much by drop in the wiring; 85V might be pushing your luck. It will depend on how well designed and built the LPSU is.

Many years ago I remember a new and very expensive piece of kit that kept shutting down due to undervoltage when we were using it in Tokyo on its 120V setting. In a bit of a hurry, I nicked the transformer out of something else less important and reconnected it as an autotransformer, with part of the secondary working as a boost winding to make 120V from 90.

 

[hippyskitz]

As the 'ballast' accepts a range of voltages, I assume it is an electronic 'lamp power supply', i.e. an SMPSU rather than a wirewound ballast. This is an important distinction. An LPSU runs at constant power and will normally drive the lamp correctly at full power or not at all. The lamp would not be underrun, as it would be with a 120V wirewound ballast. However, when the supply voltage is too low, the input current will be increased and at some voltage, the unit will shut down to protect itself. Or it should; there is a possibility of blowing its internal fuse in the meantime.

Most 120V equipment will work in Japan so long as the voltage is actually around 100V and not affected too much by drop in the wiring; 85V might be pushing your luck. It will depend on how well designed and built the LPSU is.

Many years ago I remember a new and very expensive piece of kit that kept shutting down due to undervoltage when we were using it in Tokyo on its 120V setting. In a bit of a hurry, I nicked the transformer out of something else less important and reconnected it as an autotransformer, with part of the secondary working as a boost winding to make 120V from 90.

Thanks for the detailed answer. Just for reference, this is the ballast in question.
I suppose it's not work the risk then, considering HID lights need to be regulated fairly specifically to be stable.

My next question then, would this transformer work? It says 100v to 110-120v 500w.
And this is the cheapest one I could find. Why are these transformers so damn expensive.

 

[Lucien Nunes]

Yes, it looks suitable. I think the LPSU might well be fine on 100V and it has an external AC input fuse which can be replaced easily if it doesn't like the increased supply current. But if you don't want to fiddle around testing and need max. reliability, get the transformer.

I guess the price reflects the fairly small market for that particular configuration - there can't be that many overseas electrical products imported into Japan, and of those, many will work satisfactorily on 100V anyway. Hence the reviews often mentioning US-made audio equipment, which has a cult following in the Far East and owners would be keen to ensure exactly correct operating conditions as valve amps typically have no internal regulation.

BTW I love the katakana 'ステップアップトランス' (Suteppuapputoransu).