Electricity; Just Playing

[zenoahphobic]

Using permanent magnets makes the generator free from slip rings, that presumably wearout at a greater rate than the bearings; a not completely free of moving parts system.

I think outboard electricity generation needs to change. At least from the heat point of view, flywheels can be made inverted with the magnets and coils mounted on the top instead of inside the flywheel. This however will require a frame over the flywheel, adding complexity and greater dimensions to an already large package.

As stated wasting horsepower by shunting off electricity is stupid. It is the problem from having large magnets. I can't see why you can't have a system whereby a PMG only supplies the "rotor" current, the rest of the alternator being regulated the more automobile conventional way. Yes more complex but surely more desirable than the outsized development of the permanent magnet generator causing huge heat generation and the waste of fuel and horsepower.

[boscoe99]

Using permanent magnets makes the generator free from slip rings, that presumably wearout at a greater rate than the bearings; a not completely free of moving parts system.

I think outboard electricity generation needs to change. At least from the heat point of view, flywheels can be made inverted with the magnets and coils mounted on the top instead of inside the flywheel. This however will require a frame over the flywheel, adding complexity and greater dimensions to an already large package.

As stated wasting horsepower by shunting off electricity is stupid. It is the problem from having large magnets. I can't see why you can't have a system whereby a PMG only supplies the "rotor" current, the rest of the alternator being regulated the more automobile conventional way. Yes more complex but surely more desirable than the outsized development of the permanent magnet generator causing huge heat generation and the waste of fuel and horsepower.

You would be talking about a brushless generator I believe. More expensive than a brushed type but I would think it would be cheaper than the sum of all of the parts now used in outboard motors that use what they do.

[99yam40]

OK, so it seems if the Yamaha RR is connected to the PMG , not just a rectifier and no load is tied to the RR output the AC is still loaded at 24 amps, just as it is with a loaded tied to the RR.
so the PMG will heat up so long as the yamaha RR is tied into the PMG and spinning, correct?.

I was confused

[boscoe99]

OK, so it seems if the Yamaha RR is connected to the PMG , not just a rectifier and no load is tied to the RR output the AC is still loaded at 24 amps, just as it is with a loaded tied to the RR.
so the PMG will heat up so long as the yamaha RR is tied into the PMG and spinning, correct?.

I was confused

If just the rectifier is attached, and the + and - terminals of the rectifier are not jumpered, there is no current flow.

If just the rectifier is attached, and the + and - terminals of the rectifier are jumpered, then there is current flow. Maximum current flow.

With the Yamaha R/R connected it jumpers itself internally. Trying to keep the voltage at a certain value. Current flow is similar to just what is seen in the rectifier only when the rectifier leads are jumpered.

When there is current flowing out of the PMG it heats up. When there is no current flow it does not heat up.

[99yam40]

Is that heating up what you mentioned in the other thread about letting smoke out?

And what is that rectifier rated for in amps or watts?
I take it is a full wave rectifier

[boscoe99]

Is that heating up what you mentioned in the other thread about letting smoke out?

And what is that rectifier rated for in amps or watts?
I take it is a full wave rectifier

It is a full wave rectifier. I don't know what it is rated for in either amps or watts. Or for how long. It is not cooled so it cannot be too much.

I have two different stators. Using the same permanent magnet rotor with one stator I get high voltage and low amps. With the other the I get low voltage and high amps.

I used the high voltage low amp stator first. With the rectifier drawing ~ 25 amps there was no problem. When I switched to the low voltage high amp stator I notice a bit of smoke coming from the jumper wire that bridge the + and - terminals of the rectifier. In no time at all. I looked at the ammeter and it was indicating 0. Did not make sense. Turned the PMA drive motor off.

I then realized that my clamp on ammeter is rated to only 100 amps. I reapplied power to the PMA drive motor and saw the amps go from 0, up through 100, and back to 0 again. So all I know is that the PMA was outputting more than 100 amps. I won't use that stator anymore.

So far this has been a pretty good learning experience for me. Particularly with respect to stator windings. Fine wires, thick wires, low resistance wires, high resistance wires, wye windings, delta windings, etc.. All have different output characteristics.

[99yam40]

too bad you did not get a voltage reading at least.
What RPM were you turning it.
maybe cut the RPM in 1/2 again to see if you can get current you can measure or
need to get your hands on some CTs so you can measure the output above 100.

I worked around a couple of EEs that were real knowledgeable about all of this electrical stuff.
I could ask a question and they could talk for 30 minutes about stuff I have no idea what they were talking about.
I guess I should have gone to more school instead of just working with my hands
we had them all stumped once on a pump motor variable frequency & voltage drive.
when the engineer from Japan came over to set it up and get it running.
the phase angle of the controls where off from the main power at an angle that they all thought was impossible to get.
they were all scratching their heads for days.
Turned out a transformer we hooked into for the controls was wound in the wrong polarity (addative or subtractive) I do not remember which

we blew diodes and fuses before they figured it all out when someone hooked up the test equipment wrong one day and everything looked in sync. so they hit the start button.

this was a big drive.
built a building for it.
installed a 10 ton A/C system in the building. after we got it running the Jap EE stayed working while the rest of us went to lunch. when we came back he was sweating badly and it was very warm in that building.
seems they sized the A/C for the size of building, but did not account for the heat generated by the drive.

[rodbolt17]

30 some odd years ago, if you gave me the gauss strength of the magnents,the number of magnents the speed of the magnents passing the coil and thje air gap between the magnents and the number of turns and wire size of the coil of the stator, I could have given a rough estimate of max current.
I could desighn a RR that can supply at 500 amps at 14V.
the heat loss will be horrendous.
I can weld at 60 amps.
most modern V6 V8 Yamaha four strokes can make 60 amps.
and that is why the RR is water cooled.
now all I do is deal with the complaint on the W/O and patch the dang thing till next time.
every customer comes in saying it is doing the same thing, is it warrenty??

[rodbolt17]

ya really wanna see something.
google amplydine.
someone shorted the windings of a DC generator and found a result.
and yes I worked on them.

[boscoe99]

too bad you did not get a voltage reading at least.
What RPM were you turning it.
maybe cut the RPM in 1/2 again to see if you can get current you can measure or
need to get your hands on some CTs so you can measure the output above 100.
.

I did not write down the voltage but it was in the 20 ~ 30 range. I have another clamp on meter that registers above 100 amps. I will give it a try.

Will also lower the RPM to see the affect.

From a website I frequent, here are some voltage/amp curves based on the use of different windings within the stator. Same rotor is being used. Clearly the stator makes a big difference.

[99yam40]

You may need a load of some kind instead of just a shorting wire.
space heater or hair drier maybe
You have any idea what RPM it was turning?
does it look like it fit/followed the charts

[boscoe99]

You may need a load of some kind instead of just a shorting wire.
space heater or hair drier maybe
You have any idea what RPM it was turning?
does it look like it fit/followed the charts

I just measured the voltage at 1218 RPM. Less RPM than the earlier test. ~24 volts.

Going out to get some terminals that I need. Will then test with some loads and directly jumpered to see what is to be seen.

I can't correlate it with any of the results on the charts. I only have four RPM's available. Wish I had a variable speed drive motor but don't.

[walleye1]

Can you use a dimmer switch?

[99yam40]

I just measured the voltage at 1218 RPM. Less RPM than the earlier test. ~24 volts.

Going out to get some terminals that I need. Will then test with some loads and directly jumpered to see what is to be seen.

I can't correlate it with any of the results on the charts. I only have four RPM's available. Wish I had a variable speed drive motor but don't.

I was just thinks about if the RPMs you tested showed voltage and current close to what the chart showed.

Can you use a dimmer switch?

we need to know where you think a dimmer switch would do anything on this set up

[boscoe99]

Can you use a dimmer switch?

Not on an AC induction type motor. At 5 HP 220 volts that baby is drawing some serious power as well.