Comment by silexia

2 months ago

I am a farmer with giant water pumps and center pivots that run on 3 phase 480 volt power. One of my pumps has 85 horsepower. I wonder if I could wire up some sort of custom made tea kettle and get water to boil in five seconds?

15 comments

silexia

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quickthrowman  2 months ago

You could run (10) of these 9kW 480V three-phase immersion heaters [0] in place of your 85 HP motor, assuming ~110A FLA @ 480V = 91.5kW. The 9kW immersion heaters are 10.8A each at 480V three-phase (would be 75A if it was 120V single-phase!)

Just make sure you have somewhere for the steam to go, it takes up a bit more room than water ;)

Is your three-phase a corner-grounded delta service? I’ve never seen one in the wild but I hear they’re used for three-phase ag service drops that are strictly used to run motors. A and C are tapped normally on the secondary but the B phase is bonded to ground and also a line conductor, conductor color is white for B phase instead of orange.

[0] https://iseinc.com/_shop/480v-3ph-9kw-immersion-heater-47-14...

wcoenen  2 months ago

For a small amount of water, I would be afraid of flashing the water into steam, and the resulting steam explosion.

  • mesrik  2 months ago

    Well, that's about what happens in Sauna with electric stove.

    In Finland we do it every day and have done decades already.

    Those who may not know electric stoves have been about fifty years common use at least in urban environments. Stoves have anything from three, one in each of three phase current used heating elements (resistor coils) 400V 6-8 kW power draw commonly in small house stoves and 2-3 times that swimming baths saunas stoves.

    While sitting topmost sauna benches bathing, we throw fresh water from bucket with a sauna laddle (saunakauha) water to stove(s) anything from small drippings to a pint with trying to little spread it out. This is to get steam and make it pleasant relaxing 'löyly' as we call it.

    The stove is usually heated about an hour or so before starting bathing to get temperature somewhere 70°-100°C (158-212°F).

    It's not advisable to have stove showing those red hot glowing elements peeking out behind stones, but it does happen if stones were not laid properly. But even if water gets directly to elements those will not break or get any damage as they are made intentionally to resist that.

    So boiling water practically immediately does happen, it's not particularly dangerous when applied in circumstances where equipment is made to withstand that is nothing miraculous. And that really happens millions of times each day in Finland and some other places where that kind of sauna culture is practised both at people private homes and also public swimming baths saunas alike.

    I will be observing it next time about in 14 hours from this writing as I'm going swimming as usual tomorrow morning at 6:00 am. when pool opens early tomorrow, and then likewise twice more (Wed, Fri). Also once more (Thu) evening sauna reservation slot i've got this flat I live.

    There is a quite good english page about Finish sauna in Wikipedia, but to get a glimpse what modern sauna and stoves look Harvia a long time stove manufacturer web pages you get some sense what I'm writing about.

    - https://www.harvia.com/en/

    • buildbot  2 months ago

      It’s a good point but there might be a pretty big difference in force because the ladled pint of water is not contained on any axis. A pint of water in a cup, with up as the only exit, subjected to the full current of a 3 phase 480v circuit is probably going to generate a good size jet of steam straight up.

      1 reply →

4gotunameagain  2 months ago

For sure, you could use six 240V heating elements wired in series in three pairs to get their rated power.

Of you can wire 240V elements directly to 480V to quadruple the power, as shown in the video ;)

ahartmetz  2 months ago

There is something like that in the original video - running a 120 V kettle at 240 V makes it boil four times as fast. But only a few times.