Internal Alternator windings

Not sure where you are going with this. More details would be helpful. A normal car alternator with an external regulator needs more than 10.5V to activate the filed circuit. Output is really regulated by adjusting the field current not the voltage.

yeah, elnav is right. Going to need the rpm of the alternator and the load that is across it when you want to start it. Even the age (well, the amount of dirt in the stator) is going to be a factor.

What kind of regulator are you using?

We have been testing at rpm's from 600-1000 rpm. Cleaned all of the rotor & stator surfaces. We are now wondering if there needs to be a load, and what kind of a load, in order for it to actually produce?

We have been toying with getting more out of an alternator. I was told that one can get three-phase out of a unit if the right things were done. We took out the regulator, bypassed the diodes and tailed out the three winding taps. After cleaning the sliprings and reassembling the best we can get out of it is .5 volts. We put a 900 ah, 12 volt battery on the rotor connections to hopefully create enough flux to get things moving, but it did not work as we had hoped.

Sounds like there is an internal problem.

Greyhound used to use our alternators with no regulator to run their air conditioning.

The field was simply fed by the output. Output voltage could go up to around 90 volts as I recall. If you put an adequate load on, it will max out at the rating of the machine if all is well.

good luck

Are you talking about more voltage or more current? When you gutted the alternator what exactly did you do about the field winding?

Many alternators require regulated current through the field winding to generate any output. Only those that are "self excited" have sufficient residual magnetism in the rotor pole pieces to generate enough energy to feed back to the regulator and field windings to produce usable output. Many models do not.

We just tailed out the connections for the brushes and tried a 12volt battery to excite it. But nothing over .55 volt AC between the windings ever was seen. I wolud have thought that it would have created enough field in the rotor to induce more of an output from the stator windings. We have been spinning it up in a lathe to about 1000 RPM. Could it be too fast?

I don't know what to do now. Any ideas?

1000 rpm isn't too fast. It could be on the slow side. Alternator runs at ~ 2 x engine speed so can easily do 10000 rpm.

Codey

The 12Volt was a jumper battery, 900Ah. I did not check the current. I will try to spinit up higher & meg the rotor winding.

Interesting.

Presumably there is no break in the rotor winding? 0.5 volt output sounds like what you'd get from the residual magnetism in the rotor. What field current did the 12 volt supply give?

I suppose it's a 12 volt alternator, and with 12 volt applied to the field it should produce > 12 volt at anything above ~ 1000 rpm.

It doesn't matter whether the 3-phase is connected to a load, it should still give volts. Elementary, but I trust you're using an AC voltmeter?

Cheers....Codey

Checking the voltage with a digital auto-ranging meter. I will change over to another.

It is a 12volt bus alternator. We wanted to try to make one of those Stanley Meyer Hydrogen cells. We built the frequency box to dial-in the 12volt pulse freq. to the field winding, but we can't get the alternator to do sqwat even on its own, without the box.

I'd expect rotor resistance 3 - 4 ohm (~ 3 amp at 12 volt). If the rotor winding is OK I don't see you shouldn't get about 12 volt between any 2 stator leads (at 1000rpm, a lot more if you run it faster).

I'm not familiar with Stanley Meyer Hydrogen cells and I don't know know what We built the frequency box to dial-in the 12 volt pulse freq. to the field winding means. All the field (rotor) wants is direct current. I assumed from earlier message you were putting the 12 volt battery straight on, which should be OK. Please explain a bit more.

Cheers.........Codey

What the box does is sends the 12 volts in a pulse at an adjustable rate or frequency which then, in Mr. Meyers build, created the HHO in a more productive fashion that is with less amperage draw.

http://en.wikipedia.org/wiki/Stanley_Meyer

The regular HHO cells which are all over the internet now due to the high cost of fuels, pull down the cars electrical system too much to be really effective. With this system it will be less strain on the regular alternator and produce more fuel gas. Really not a new thing, it's been used & patents issued back in the 30's

Is that 3-4 ohms as measured directly on the slip rings, or at the terminals on the outside?

OK I understand a bit more now, at least the pulse frequency box is on the output side, I thought maybe it was messing up the field supply.

But first things first, I think you need to make sure you have 3-phase AC output before connecting to the pulse frequency box.

Is that 3-4 ohms as measured directly on the slip rings, or at the terminals on the outside? - difference should be negligible, as the brushes and leads have low resistance. If there is a difference - higher resistance at the terminals - it suggests a problem with the brushes/leads. 3 - 4 ohm is my best guess, but I've got several alternators and parts of at home, I'll take a measurement this evening and drop a post.

Also, while I said earlier I'd expect ~ 12 volt at 1000 rpm, you won't get much current at that speed (assuming it's connected to a load, say a flattish battery). The current rises rapidly with increasing speed.

Cheers......Codey

Rotor resistance - checked it and got 3 - 4 ohm (it's a basic ohmeter reading to nearest ohm, no decimal, and it flicked between 3 and 4).

Also dug out some literature (old but I doubt it's changed) which said 3.35 - 5 ohm depending on model and make - Lucas, Bosch, Femsa.

Cheers......Codey

There are two thresholds needed. One is to have enough revolutions per minute to get any meaningful output and the other is field current.

When I worked at Leece Neville back in the '60s, we would tie the field to the output and crank them up on a variable speed drive. Most of the commercial automobile types would reach full output voltage capability at around 600-700 rpm. The max current capability was determined by the current in the field and the winding resistance of the stator. They would self excite after flashing the field only once on a battery. Most of the machines were capable of 10,000+ rpm and that is where we would life test them.

Hey Satcom Bill, did you ever work on the VFL series alternators?

No, not familiar with VFL acronym.

I take it hat VFL is Variable Freq. Level?

That would be just the ticket for us. Higher frequency is much more productive....

Normally you need to excite these windings with a little over 12 v. in a 12 v.

system.One way is to hardwire a line from the battery through an alternator

switch , then to the windings.