easy way to generate an ac signal

[The Natural Philosopher]

The signal then needs to be processed, that bit I can handle.

bet a cheap brushless motor from somewhere - model aircraft type. That gives 3 phase AC

[Dave Plowman (News)]

Where on earth did you get that daft idea?

[Bill Wright]

So, you're one of these lefty/greeny Guardian-reading schoolteachers who are brainwashing our children into believing all the global warming bollocks are you?

Windmills my arse.

Bill

[polygonum]

Bill,

You are leaping to conclusions. The experiment, if done well, would show that windmills are not the answer.

[Bill Wright]

Mine don't seem to.

Bill

[Bill Wright]

Or a hub dynamo.

Bill

[misterroy]

No, I'm pretty pro nuclear and anti feed in tariff. I try and give them a propaganda free view, but that is not what I am supplied with.

[misterroy]

shed that you can modify to get the AC out.

one to spin the other. Or it to the back of a PC and run it from the fan in that.

shed that you can modify to get the AC out.

one to spin the other. Or it to the back of a PC and run it from the fan in that.

shed that you can modify to get the AC out.

one to spin the other. Or it to the back of a PC and run it from the fan in that.

I have an old dynamo in the shed, knew it would come in useful, (looks like today is someday). I'll put it on the scope at work tomorrow. ta

[Onetap]

Where do you think? From trying to jump start a car with a totally knackered battery. I've done it dozens of times before, this was the only time I've had a problem; new alternator required.

I looked into it and found a web page about alternators with external diodes for use in light aircraft. Apparently flicking off one of the isolators (battery I think) required in an aircraft would wreck the diodes in a conventional alternator.

[Onetap]

Mine didn't either for the past 30 years. I THINK the essential difference was this battery was totally US and I didn't know it.

[Andy Champ]

The signal then needs to be processed, that bit I can handle.

Have you still got the Nuffield kits we used all those years ago to make electric motors? Make one with more than the usual number of coils, and you should be away.

Andy

[Dave Liquorice]

A lot of modern car User Manuals warn against jump starting but not the reason(s) why it is not recomended.

[Andy Dingley]

using a drill.

Brushless motor. Under a tenner from eBay. It's a 3 phase alternator, just = like you might use for a real wind turbine. Then 6 diodes give you a bridg= e rectifier and DC output.

Otherwise almost any sort of fixed coil and a whirling rare earth magnet.

You can even make your own wind turbine. A crude 3' diameter (flat plywood = or Correx plastic blades) makes a workable demo. Use the Tim Piggott design= (search the web for a US site building them with Volvo 240 front hubs). Y= ou can make a simplified version of this in a CDT class - use a bike hub or= similar, especially if you can get one with a disk brake.

[Jules Richardson]

No, the experiment will show that windmills can work, but only if you have a drill of approximately the same size as the windmill.

[polygonum]

Indeed. Windmills do work in one sense of "work".

[tony sayer]

Umm .. why should jump starting a car with a flat battery fry the alternator diodes?...

[Dave Plowman (News)]

I'd say the type I mentioned easier to mount on something and drive with an electric drill?

We are talking about a school teacher so need to keep things as simple as possible. ;-)

[Dave Plowman (News)]

That was probably why the battery was flat...

With the engine running?

[Dave Plowman (News)]

My BMW with boot mounted battery has contacts on the engine specifically for jump starting.

[The Natural Philosopher]

battery to inverter to bulb.

Just get a cheap brushless motor.

e.g.

magnets round a fixed three phase winding.

Like to be driven at many thousand RPM for decent voltage tho.

but an ac motor would be a neater solution and it would be possible to mount the blades. The turbine has to generate an AC signal.