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Title: Transformer from grow lamp power unit - Useful? Post by: WB6NVH on February 07, 2020, 05:20:49 AM I hauled home a grow lamp type power unit from the dump as it has a nice steel enclosure for a power supply project I have in mind. I noted that there is a big transformer in it rated at 430 Watts with tapped primaries, going to a capacitor and some kind of starter unit in a tubular housing. I think this is for the metal halide lamps.
I was wondering if anyone has tried re-purposing these things. Unfortunately there is no center tap and I don't know the secondary voltage until I get some spare time with a VOM. I am wondering whether this is just a standard power transformer or something with special core magnetics or configurations making it unsuitable for something like a medium sized transmitter power transformer. All I find on the web on the subject is unrelated fussing from marijuana growers. Geoff WB6NVH Monterey CA Title: Re: Transformer from grow lamp power unit - Useful? Post by: Detroit47 on February 08, 2020, 09:38:42 PM About 10 cents a pound scrap.
Title: Re: Transformer from grow lamp power unit - Useful? Post by: w4bfs on February 09, 2020, 01:45:44 PM just to protect your dmm or vom from unexpected hv, start the 120V primary with 10V or so from a variac... current monitoring very informative :-X
Title: Re: Transformer from grow lamp power unit - Useful? Post by: WB6NVH on February 14, 2020, 11:38:09 AM I just wanted the enclosure so anything else was gravy.
Turns out the secondary, which is isolated from the primary, is about 165 Volts, not useful for much although with a variac in the primary it could possibly make an isolation transformer as it is rated 400W. In the meantime it may very well wind up as a doorstop. Title: Re: Transformer from grow lamp power unit - Useful? Post by: W2PFY on February 14, 2020, 04:01:44 PM Well a lot depends on the color of the box?
Title: Re: Transformer from grow lamp power unit - Useful? Post by: WD5JKO on February 14, 2020, 04:43:40 PM Geoff, I used to work in R&D for a company that built ballast transformers for Mercury, Metal Halide, and High Pressure Sodium lamps. The only one of the three that needed a starter was High Pressure Sodium, several KV as I recall. I was on a TAC Transistorized Arc Control project where we used some early generation FET's from International Rectum Frier (IR) as we used to call them. This was for Mercury and Metal Halide lamps. At the 400 watt level, these lamps when hot took about 140v at around 3 amps RMS. When cold, the current needed to be limited since the arc voltage was low, perhaps 50v cold, and as the bulb plasma warmed, the arc voltage rises. The point being, your transformer is more of a sloppy current source than a voltage source. Not real useful if you like a stiffly regulated voltage source. If this Tranny comes apart, then perhaps there is hope to reconfigure things (remove the "Shunts" and have the windings one over the other). Question: in the day (1970's), they used to weld the lamination's together to simplify and lower the cost of assembly. Then due to the high Eddy current losses, they changed the insulation to Class H which has a very high temperature rating. Marketing ran with that, "Uses Class H Insulation" when our competitors do not! Jim Wd5JKO |