OT: HP of an electric motor?

You'll need to make sure any replacement motor runs at the same speed or you'll foul up the cutting speeds :((

Pferdestarke

735.5W 1 PS = 1 CV

Have a look at:

Regards

Phil Gardiner

alt.fan.landrover FAQ compiler:

You should be able to use the smaller motor as long as you are prepared to take light cuts, turn at lower speeds etc. My next door neighbour is using a

2hp motor on a very big lathe for the same sort of reason as you are - no three phase. In my case I run a small lathe (550w) on solar power - they wanted $33,000 to put power on, and that was ten years ago. JD

It's fraught with difficulties. For example, I had a 2HP outboard motor, which I guess would propel my little dinghy a lot faster than a pair of Dutch Warmbloods. But the much larger Dartmouth - Kingswear ferry was, in days of yore, powered by a couple of nags, where my outboard would have been way out of its depth (metaphorically).

Conversely, I think my hundred-and-something HP Disco would be hard pushed to win a tug-of-war against a hundred or so horses, even with a great set of tyres. But even with a very impressive drivetrain, would the herd be able to pull 80mph down the M3?

This all makes me wonder if horses are better at torque than power, but then I've never really understood the differences between them, frankly.

David

It is possible to convert single phase to 3 phase, however my Father is the Electrical engineer, not me. He tells me there is a "cheat" way of doing it. If you're really interested I could ask him, but it is liable to mean purchasing some components and making a large gubbins to do it.

And yes, it'll need a starting capacitor, 2/3hp single phase motors take a hell of a kick on starting.

(jealousy mode on)

On the other had I don't see why I should help you as I don't have a lathe of my own

(jealousy mode off)

Alex

The other way round!

And there are more:

1kw = 1.34102 UK HP 1kw = 1.34048 Electric HP 1kw = 1.35962 Metric HP 1kw = 1.34041 Water HP

Alex

Power = torque x speed.

Power is the thing if you want outright pace. Torque is good if you want an engine that produces good power with less dependence on how many revs you have on the dial. If you think it through, engines that produce max torque at low RPM will have a more constant power delivery than ones that produce max torque high up. An even spread of power through the RPM range means less stirring of the gearbox...

That said, it would be easily to characterise an engine as peaky if it produces max torque at 4000 rpm. However, it may still produce 99% of that max torque at 1500 rpm, so actually be pretty flexible - often overlooked just by reading the engine stats.

BTW, electric motors produce max torque at zero rpm.

Tim Hobbs

'58 Series 2 '77 101FC Ambulance '95 Discovery V8i

The message from "David_LLAMA4x4" contains these words:

Wire in a 30 amp supply to motor point. go to

and order document JEPH13 "run 3 phase on mains" for a circuit costing a few pounds to run the three phase motor. Tip from an engineer I know; get a smallish 3 phase motor with a small flywheel, start this first on the same wireing circuit as the lathe and it will give you a whole lot more starting torque if you turn on the lathe after the small motor is up to speed.

usual disclaimer, if it all goes pear shaped you are on your own! DO NOT TRY THIS AT HOME WARNING ELECTRICITY IS DANGEROUS 3 PHASE IS VERY DANGEROUS AS ARE LARGE CAPACITORS.

On or around Wed, 2 Jul 2003 22:17:16 +0100, "David French" enlightened us thusly:

nothing's that simple...

in an inductive load the voltage and current are not in phase. How much they're not in phase depends on the inductance. There are nasty equations to work it all out.

but practically speaking, as stated above, you may find that someone's measured it and marked it on the motor. Failing that, in theory, you can get an inductance meter and work it out.

On or around Wed, 2 Jul 2003 09:27:38 +0100, "Tony Bartels" enlightened us thusly:

Machine Mart will sell you motors and starters up to 4hp single phase, for a price. not sure if they'll run a lathe, mind - ought to be OK. They're no good for high-torque starting, apparently, but you don't do that on a lathe, mostly

On or around Wed, 2 Jul 2003 18:41:23 +0100, "Adrian England" enlightened us thusly:

see?

seem to be the same as the PK in Belgium - I reckon it's a wimpy euro-spec horse.

Bruce must have been lucky when he had the three phase put in to the workshop when he first moved in, as he only had to pay £1000 towards the costs, about 16 years ago, not long before I met him.

On or around Wed, 2 Jul 2003 07:51:36 +0100, "David_LLAMA4x4" enlightened us thusly:

you have to have a circular path, and an arm which rotates, to which you tie the horse. Horse goes round in circles, thereby making a shaft turn in the middle, which you gear up suitably. Mind you, it occupies a lot of space. On the plus side, it produces good fertiliser for yer roses. Reasonably easy to upgrade it from 1hp to 2hp, and by suitable selection of horses you could get 1.5 hp etc. If you want more than about 4hp, you'd have to make the track longer, or the horses would get too close.

As an alternative, you could have a rank of hamsters in wheels. I suspect you'd need rather a lot of 'em, but the advantage of this system would be that the failure of one animal would make only a small difference to the available power. As an additional benefit, you could, when not running the lathe, use the hamster array (connected to a suitable generator) as a power supply for the PC so as to be able to read news at no extra cost.

In case someone thinks the hamster array sounds cruel, It should be pointed out that hamsters willingly spend considerable time trundling around in wheels - given enough hamsters, you'd have enough of them that most of your power would be available on a voluntary basis.

The big old lathe in the farm workshop runs on a single 13A supply. The drive goes through a countershaft to get enough speed reduction. I'm not sure that I can read the plate on the motor. The old flat belts on the final drive will slip if the load gets too high.

It'll need a bit of figuring to work out required motor speeds for a particular cutting speed on a particular radius.

Or just use a treadmill, which although more mechanically challenging, is more easily adaptable to larger numbers of horses without running into differential problems. (That's the way the Dartmouth ferry used to work.)

Or, you could build on Austin's idea by building a giant hamster wheel for the horse. Getting the horse into it may require a brake though, or a gymnastic horse.

David

A good way to estimate how flexible an engine is from the published figures is to look at the spread in rpm between maximum torque and maximum power - the wider the difference, the more flexible the engine. JD

Not for generating electricity. If the wheel was stationary, the horse may be able to vie with the forces of gravity, up to a point (a la Matrix). But as soon as you spin the wheel, the horse plummets!

They don't call it the wall of death for nothing.