Way back now when our son was a toddler, we discovered he had chronic Asthma. Hospital visits and oxygen tents etc. Well we needed a nebuliser. I forget the cost of them then, but we couldn't afford one. So I looked at what I had in the garage. I found a 12v tire pump I had brought in PNG in the mid 70's, found a dimmer control, a transformer out of a TV and a diode set out of a Holden alternator. using the dimmer control to vary the 240 voltage, then ran that through the transformer and connected two 6volt windings together to get 12v. Put that through the diode rectifier and that ran the tire pump. Mounted the whole lot in a fishing tackle box. Talked it over with the doctor, and as long as the pump used no oil which it didn't it would be OK.
It served us through all the sons trauma as well as out youngest daughter who got exercise Asthma. So it probably worked through about 15 years, until I pulled it apart and used it again as a tire pump. I think the pump has had it now, but I still have it.
The variable voltage (dimmer) worked perfectly, and the pump could work from the car when required.
Just a little story that I thought you may be interested in.
I'm happy it worked for you, but I would think that the transformer would have seen a horrible waveform on its primary. Also, the rectified, unfiltered (?) secondary waveform wouldn't have been very nice for the DC motor. However, I suppose that the usage pattern would have amounted to no more than a few seconds a couple of times per day. Nice work in any case.
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"No friend ever served me, and no enemy ever wronged me, whom I have not repaid in full."
