Every standby (and sometimes main) boiler feed pump on every single power station in the country, gas circulators on AGR's, circulating water pumps and the boiler fans... all induction motors, mostly supplied at 11kV or 6.6kV
500kW a piece for an AGR gas circulator, same for a circulating water pump and a boiler fan, 5MW for a standby boiler feed pump
I can't recall what UK site has (or had) an electric rather than steam driven main boiler feed pump but it was rated in the region of 10MW.
You're probably thinking of that damned Parkside PGI 1200 A1 inverter genset. :-)
Told ya!
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Never mind, if you hurry, you'll probably still be able to get hold of one of those inverter gensets that went "on offer" today. :-)
If the extra 30 quid had represented an electric start option over the later PGI 1200 B2 version they'd been flogging two months ago, I might have been tempted. Personally speaking, the retro chic 1990s two stroke
720W genset styling, which I assume to be the reason for that 30 quid price hike, just doesn't "Do It" for me.
Petrol mowers stall then you have to start them again. Electric mowers = you just ease off the work it has to do if it begins to slow down. An e= lectric motor by it's very nature gives out more power when it runs slow= er. Oh and you don't have to maintain the bloody engine! I do love wat= ching people having trouble getting them to start - they're not like car= s with 4 or more cylinders. They have one cylinder, which means they n= ever bloody start. And AFAIK they use carburettors instead of injection= like modern cars. If you're old enough to remember carburettors in car= s, you'll know why these should be avoided at all costs. They're like w= omen, they get all flustered easily and flood the engine. The only adva= ntage people claim for petrol mowers is there's no cord to get in the wa= y. Well that isn't a problem if you have the slightest bit of common se= nse. You plug the mower in at the edge of the lawn (say your garage or = house or whatever), then simply mow up and down the lawn =
moving away from the electrical outlet. The cord just drags behind you,= at no point do you ever have to shift the cord out of the way.
Max torque for an induction motor is at 25% slip (which is around 80% free running speed), but you don't design for that high a load because you are too near to stalling. Normal max design slip is 20% slip (around 85% free running speed). This is why it's perfect for cutting grass - max torque is still at a high enough speed to cut grass.
Max torque for a universal motor is locked rotor (stalled, stationary). In the normal region of operation where speed is high enough to cut grass, the motor's torque is lowest, which makes maintaining that grass cutting speed under load much less likely. The motor is unlikely to completely stall because the torque gets very high as it gets close, but the torque is low at minimum effective cutting speed, so it easily drops below effective cutting speed with load, and thus not so suitable for grass cutting.
Hum, maybe you are confusing induction motors with synchronous motors, used for old mains clocks and timeswitches?
Serious power motors are *exclusively* induction motors - no other type is used.
We are away in the caravan in a three acre field. When we arrived the farmer had just given up on trying to mow it, because his full size tractor / mower was constantly choking up with cuttings.
Mowed my lawns this morning. Was quite a load as it's gown a lot in
2 weeks. Just after I started with my electric mower, I heard next door's petrol mower start up, and then stall as soon as it hit the grass. Then lots of tugging on the starter and it's off again, only to stall when it hits the lawn again. This cycle continued until after I finished mowing my lawns, and was still going on as I went out. Couldn't help thinking of this thread!
Back now after a lovely 2 hour cycle ride which included lunch out, and either they've managed to finish their lawn, or they've given up (I can't see it over the fence), because there's no more mower sound.
Can?t help thinking that it?s either a particularly feeble mower or very long grass. I guess if it was a self-propelled one it might have just been driving forward too fast for the length of grass.
I?ve certainly never regretted moving from an electric mower to petrol.
On the other hand, my electric hover-mower struggles badly with long grass and is extremely tiring to use. Today I was given a petrol mower that was no longer needed (parents' French holiday being sold). Started on the second pull and it cut grass that should have been mown a month ago with ease. No hesitation, no pushing hard to move it (it has driven wheels) and the whole garden was done in a quarter of the time that it would have taken with the electric mower - and that was with a second cut (that I don't normally do) on a lower height setting! I was amazed at the ease. The large grass collector meant only emptying it twice, compared to 5 or 6 times for the electric mower too.
A petrol mower is a bit of an overkill for our size of garden, but when it's free and makes it so much quicker and easier to mow, I'm willing to sacrifice a bit more storage space for it - the electric mower hung on the wall.
Lots of industrial motors are driven directly from 50Hz (or 60Hz for some installations).
The largest motor I have had on a piece of equipment was a compressor drive. It ran fixed frequency on a 50Hz supply and a variable speed drive would have been redundant in this use - and damned expensive on an
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