Electricity; Just Playing

[boscoe99]

I set up a test rig to measure AC and DC output from a permanent magnet generator. Similar to a Yamaha rotor and lighting coil. Results for two rotor speeds are shown below. Got two more to do. One at 2318 RPM and one at 3032 RPM.

Difference being that in my PMG the magnets are on the inside of the coil whereas on a Yam the magnets are on the outside of the coil. Faster spinning magnets create more electrical power.

My rig only has 7 magnets whereas a Yamaha has up to 12. A Yam turning 6000 RPM with 12 magnets will have a serious frequency. 1200 Hz if my math is correct.

Gonna power a Yam R/R with isolater lead functionality to see what happens.

I can see someone (me) killing themselves with this much AC voltage if not careful.

[99yam40]

question, what does this PMG come off of?
I have been out of the automotive repair for a long time, but had no idea they had PMG in them if they do

[panasonic]

I like the bungee cord belt tensioner!

[boscoe99]

question, what does this PMG come off of?
I have been out of the automotive repair for a long time, but had no idea they had PMG in them if they do

It is an AC Delco alternator that has had a rotor with permanent magnets that replaces the conventional eletromagnetic rotor. Damn strong magnets I might add.

[boscoe99]

I like the bungee cord belt tensioner!

Quick and easy to take tension off the PMG so that pulleys can be changed to vary the speeds. Wish I had a variable speed motor but it was too much bucks.

[zenoahphobic]

Interesting, powerful permanent magnets of today make the alternator more efficient as no electricity or power is required to the rotar. On the other hand you have a hell of a time regulating the output that looses that efficiency very rapidly.

I wonder if you could adjust the speed of the alternator (by the pulleys) to get the maximum power output; that is maximum current at 14.5volts over the engine Rpm range from 900 to 6000, if you are trying to simulate a Yamaha engine and using a Yam R/R. It would be interesting how stable the output can be made over that range and what minimum wastage (shunting to earth) in the regulator can be achieved.

I guess what was available to vary by Yamaha designers was the diameter of the flywheel, the number of magnets (or strength), and the turns in the windings of the stator to achieve maximisation of power output. I wonder how well they have achieved that objective?

[99yam40]

It is an AC Delco alternator that has had a rotor with permanent magnets that replaces the conventional eletromagnetic rotor. Damn strong magnets I might add.

what vehicles run these PMGs and what are they rated at current wise?

what kind of rectifier/regulators do they use in the vehicles they are installed on?

How long have these PMGs been around?

[boscoe99]

They are not used on any car or truck that I know of. They are intended to be used for either wind power (wind mill) or hydro power (damned up water) electrical generation. Mostly to recharge batteries. For use out in the boonies. Where it is not fit for man nor beast.

Current is a function of the generator speed. I am going to be testing mine to see what is the maximum current output at four different speeds. There are much bigger ones available. I bought what I have to fit my budget and just see what happens and when.

https://mwands.com/

[99yam40]

You fixen to move out away from everyone?

[boscoe99]

No, but I would not mind being there.

[99yam40]

Do you think that that elect motor will handle the load at the upper output?
I think I remember that it took about 7 HP to run an alternator an a automobile.
but that was many years ago

[boscoe99]

Do you think that that elect motor will handle the load at the upper output?
I think I remember that it took about 7 HP to run an alternator an a automobile.
but that was many years ago

Good point. I started with a washing machine motor. Stalled out when a load was applied. Got a 1 HP Craftsman air compressor motor at a yard sale. Stalled out under load. Took the 2 HP air compressor motor from my compressor. Stalled out under load. Got the 5 HP 240 volt motor. Have not tried it yet. If it stalls I am going to be seriously disappointed.

An automotive alternator only makes the electrical power that it needs, when it needs it. Might be nil power or might be 100% power using 7 amps to do it. A PMG makes all of the electrical power of which it is capable, all of the time. What a waste running around paying for 5/7 HP all of the time if not needed. At the risk of frying a R/R.

Remember, the electric motor will be powering the PMG. It will be making full power 100% of the time. Damn, I won't sleep tonight. Gonna go see what happens in the morning.

If it is not one damn thing it is something else.

[boscoe99]

Output of the alternator matters with respect to HP required to turn it per the innerweb. I can see a big honking one requiring 7 HP. My car needs lots of electrical power what with the electric power steering I suppose.

https://alternatorparts.com/how-much...ator-make.html

[99yam40]

are you going to hook up some type of resister/load bank?
Just wondering how you will determine max load output.

Interesting says 1 hp per 25 amps, but my guess is that is at 14 volts DC
not sure what voltage you are going to be outputing in DC

does that PMG have a wattage rating?

Since these things are for wind or water powered, they must not be turning very fast unless there is some gearing involved to speed up RPM which I am sure they would have.

seems like that PMG would have some kind of specs showing RPM and output

[ausnoelm]

Not exactly sure what you are trying to prove or "myth bust" but, output voltage with no load means very little, please explain what your experiment is attempting to achieve.