Increasing Stator Output - Rewinding Stator.

[Motogiro]

"Dictionary of Automotive Terms
Alternator
A device which produces alternating current (AC) by converting the engine's turning (mechanical) energy into alternating electrical current at all engine speeds. The AC must be rectified (converted from AC to DC) before reaching the car's electrical system . The alternator is driven by a belt at the front of the engine. Alternators replaced the direct-current (DC) generators used up to the 1960's because they were less efficient especially at idle. The electrically demanding options like air conditioning forced the use of alternators over generators. "

The story I heard on the development of the alternator was that service vehicles like milk trucks and other delivery vehicles that did a lot of stop and idle, would suffer dead batteries so they developed the alternator that was much more efficient at idle than a generator.

Also, in the days of the generator it was and still is today, a common practice to disconnect the wire from the battery, while the engine is running, to see if the charging is system is working. If the engine died your charging system was at fault. If it stayed running it was your battery that was at fault. :don'tknow:
Do Not do this with today's cars or any car with an alternator!!! It's not the same as the old generators and you can cause a lot of damage to other voltage sensitive components in the system as well.:spank:

 

[bmccrary]

I talked to Gary today and he said he pulled apart the stator today. Apparently this stator has an interesting wind which make its more difficult to get power out of. He feels certain that he can get something out of still, but not sure how much.

 

[bmccrary]

Ok guys I got the stator back.

I bolted it up, ran the bike with it unplugged and measured the output AC voltage. I have some numbers but I need to back them up against a stock stator. The shop manual only refers to resistace to measure the stator.

After talking to Gary, the owner of Custom Rewind, he wants me to get voltage readings from mine and a stock unit to compare the two.

So if any of you have access to a multimeter and are comfortable disconnection your stator from under the fuel tank and running the bike and taking some readings please contact me.

I need readings from idle, 2500 and 5500 rpms.

Ill be back and forth all afternoon so shoot me a PM for more contact or post something if you have it.

Thanks guys

-bryan

 

[Motogiro]

Ok guys I got the stator back.

I bolted it up, ran the bike with it unplugged and measured the output AC voltage. I have some numbers but I need to back them up against a stock stator. The shop manual only refers to resistace to measure the stator.

After talking to Gary, the owner of Custom Rewind, he wants me to get voltage readings from mine and a stock unit to compare the two.

So if any of you have access to a multimeter and are comfortable disconnection your stator from under the fuel tank and running the bike and taking some readings please contact me.

I need readings from idle, 2500 and 5500 rpms.

Ill be back and forth all afternoon so shoot me a PM for more contact or post something if you have it.

Thanks guys

-bryan

Assuming "unplugged" means we'd be looking strictly at the stator out put with out the Rectifier/Regulator hooked up. This could be a little tricky because with out being rectified the type of signal we're seeing can have so many variables. I would think you want to look at power, volts x amperes. This would normally be done by loading the output of the charging system and measuring current and voltage. If you look a couple of posts back you will see where we are talking about a shunting type regulator. It would have a heat sink because it has to dissipate heat. If your stator output is considerably more output you might have a little problem because the wattage at the shunt regulator is going be higher needing a larger amount of heat dissipation. It's not field regulation as is found in most regulated charging systems today.

I was talking to a guy who had a VFR and he said that the VFR was known to have regulator problems and needed them replaced often compared to other models. I couldn't think of a reason why until I became more educated by researching for this thread and finding that a lot of bike use shunt regulation.

I'm sure there's a good engineering reason to do it this way on bikes but....?

Here's hoping you're not getting a lot more power output because now you need to think about more current through the rectifiers and shunt.

 

[bmccrary]

How will there be multiple variables? I am confused. All that is happening is measuring the AC voltage coming from the stator as the motor is running. There is a 3 pin connector under the fuel tank that connects the stator to the wiring harness. Disconnect that and measure the voltage coming from the stator as the bike runs.

I cant really determine what other modifications need to be performed until I know how much extra I am getting. I have a feeling its not much more that what comes from the factory, but untill I have something to compare it to I really dont know.

Just need someone who is comfortable working on their bike to disconnect the stator and run the bike and determine the AC voltage output and/or current as well coming from the stator.

-bryan

 

[Fred]

I can test my bike. PM sent.

 

[bmccrary]

I can test my bike. PM sent.

PM sent back! Thanks Fred!

-bryan

 

[urbanj]

I can throw it on the avr tester and see what it puts out. any alternator/generator is only going to put out as much as it needs to maintain its specified voltage. so it needs to be load tested to see it's max output.

by looking at the manual it states the rectifier capacity at 25A. The ac magneto at 14V 310W at 5000rpm. and the no load regulated voltage at 14.1v-14.9v

It doesn't seem there is that much wiggle room before the rectifier gets angry.

 

[bmccrary]

Sounds like Fred is going to take care of it this weekend and we will see what he turns up. Keep in mind the numbers you are mentioning are DC voltage. The generator puts out AC voltage. That and the stator continues to generate voltage up to the red line. The faster the crank spins the more juice that comes out of it.

However, what the you are refering to is the that at ~5000 RPM the stator has produced enough AC voltage to max out rectifier at 14v, the rest of the power generate is disipated as heat. Now what rewinding the stator has done, potentially is lower the RPM range at which the recitifer is maxed. So, instead of charging the batter at 5000, I could potentially be charging the battery sitting at a red light....

I understand the fears about the excess heat. Only time will tell what will happen there. I am continuing the talk to Gary and determine a solution for this, as this is his specialty.

-bryan

 

[ant_mb]

Sounds like Fred is going to take care of it this weekend and we will see what he turns up. Keep in mind the numbers you are mentioning are DC voltage. The generator puts out AC voltage. That and the stator continues to generate voltage up to the red line. The faster the crank spins the more juice that comes out of it.

However, what the you are refering to is the that at ~5000 RPM the stator has produced enough AC voltage to max out rectifier at 14v, the rest of the power generate is disipated as heat. Now what rewinding the stator has done, potentially is lower the RPM range at which the recitifer is maxed. So, instead of charging the batter at 5000, I could potentially be charging the battery sitting at a red light....

I understand the fears about the excess heat. Only time will tell what will happen there. I am continuing the talk to Gary and determine a solution for this, as this is his specialty.

-bryan

So basically all you've done is lower the RPM range at which you charge?

 

[Motogiro]

How will there be multiple variables? I am confused. All that is happening is measuring the AC voltage coming from the stator as the motor is running. There is a 3 pin connector under the fuel tank that connects the stator to the wiring harness. Disconnect that and measure the voltage coming from the stator as the bike runs.

I cant really determine what other modifications need to be performed until I know how much extra I am getting. I have a feeling its not much more that what comes from the factory, but untill I have something to compare it to I really dont know.

Just need someone who is comfortable working on their bike to disconnect the stator and run the bike and determine the AC voltage output and/or current as well coming from the stator.

-bryan

For one I think it would be better if we developed a standard for the measurement. If your using a Fluke FL-1234 and I'm using a a Radio Shack RS-1234 digital volt meter we might not have accurate standards for comparison. That's just the meter alone. Then there are things like inductive reactance. Electrical reactance - Wikipedia, the free encyclopedia

I won't even begin to talk about these measurements with different meters at different frequencies/rpm multiplied by the inductive reactance and so on.

I promise, I'm not trying to be negative. Yes there are many variables, and hopefully all is good with your new stator, and what ever the wattage increase, it will be okay with your Regulator/Rectifier.

I'm just thinking the measurement at an open stator (star configuration) may not be the result you're looking for, to prove what increase in total wattage you're getting. You'll be looking at voltage with a fairly high impedance instrument. I'm not understanding how you will derive the needed information when you're not measuring current but only the voltage.

I hope I'm being helpful and all the best on this great project :surrender::noworries:

 

[bmccrary]

For one I think it would be better if we developed a standard for the measurement. If your using a Fluke FL-1234 and I'm using a a Radio Shack RS-1234 digital volt meter we might not have accurate standards for comparison. That's just the meter alone. Then there are things like inductive reactance. Electrical reactance - Wikipedia, the free encyclopedia

I won't even begin to talk about these measurements with different meters at different frequencies/rpm multiplied by the inductive reactance and so on.

I promise, I'm not trying to be negative. Yes there are many variables, and hopefully all is good with your new stator, and what ever the wattage increase, it will be okay with your Regulator/Rectifier.

I'm just thinking the measurement at an open stator (star configuration) may not be the result you're looking for, to prove what increase in total wattage you're getting. You'll be looking at voltage with a fairly high impedance instrument. I'm not understanding how you will derive the needed information when you're not measuring current but only the voltage.

I hope I'm being helpful and all the best on this great project :surrender::noworries:

I am not sure how it is going to work. I am simply doing as I am told by the guy at Custom Rewind. He informed me to measure the AC voltage from the stator and compare it to the stock values.

We can assume that all your stators are the same as they have been produced with the same amount wire and wire type and winding pattern. I just need to have some to base the increase, if any upon. Once I have the stock values, I will contact Gary again and see what else is needed to determine the overall increase.

I never said you were being negative. I am just struggling to understand everything that is going on here. Electrical stuff is not my strong point I will admit so I am learning as I go. I appreciate all input that is put into this topic! I really hope something is discovered here that will help out those of you that are needing the extra power for heated gear and such.

-bryan

 

[Motogiro]

I am not sure how it is going to work. I am simply doing as I am told by the guy at Custom Rewind. He informed me to measure the AC voltage from the stator and compare it to the stock values.

We can assume that all your stators are the same as they have been produced with the same amount wire and wire type and winding pattern. I just need to have some to base the increase, if any upon. Once I have the stock values, I will contact Gary again and see what else is needed to determine the overall increase.

I never said you were being negative. I am just struggling to understand everything that is going on here. Electrical stuff is not my strong point I will admit so I am learning as I go. I appreciate all input that is put into this topic! I really hope something is discovered here that will help out those of you that are needing the extra power for heated gear and such.



-bryan

Thanks Bryan,
I also have a little more info on what you're trying to accomplish since my last post (been running back and forth with post window open while you've been posting more info) and have a better understanding of what you are expecting and the concept seems a lot more relevant knowing that you're talking about increased lower rpm output. That would truly be an excellent mod to accomplish with these charging systems. I hope you're successful with this cuz I'll be the first to jump on this mod. I'm also,always learning!

Thank you again!

 

[bmccrary]

So basically all you've done is lower the RPM range at which you charge?

Basically, yes. With the voltage regulator/rectifier in the loop, it really is the limiting factor. If I get more than 22amps or 14.4 volts I risk blowing the battery, lights and everything else in the electrical system.

So in essence, yes I hopefully have just lowered the RPM range at which it is fully charged. Depending on how much juice, and how low the RPM range I have dropped will determine the real increase. I mean being able to fully charge at idle will be amazing! You could easily run more lights and heated gear with that as you would be able to maintain the charge on the battery easier and sooner.

-bryan

 

[bmccrary]

Ok so I just spent some time researching the power equations for an AC circuit.

When taking the measurments off the stator I was using a Fluke 83-III or something. (G/F's mom is a electrical engineer, borrowed hers)

I took the voltage readings at three different RPM ranges, including idle, 2500 and 5500. The voltage across the stator output terminals was found to be, 23.5V, 35.0V and 83.0V, respectfully.

Using the calculations I found to be Vrms = Vpeak/sqrt(2)
Pavg = Vrms^2/R

where R is 0.5 ohms, the resistance in the stator winding.

With these values and those equations I am getting my output at idle to be 552 watts, and at 5500 RPM's 6889 watts. So Im not really sure on these calculations at this point. Seems a bit high to me?

-bryan

 

[bd43]

Those voltages were taken on open ended leads? The formulas which include resistance are across a known resistive load. No load, no power.

 

[bmccrary]

Those voltages were taken on open ended leads? The formulas which include resistance are across a known resistive load. No load, no power.

So the resistance in the stator doesn't count? Then how in the world did the manufactures figure out how much power is being supplied to the rectifier?

-bryan

 

[RJ2112]

So the resistance in the stator doesn't count? Then how in the world did the manufactures figure out how much power is being supplied to the rectifier?

-bryan

...... with a load applied of known resistance/impedeance.....

 

[bmccrary]

and those values are? lol.

This is proving more difficult that first imagined. Im hoping Gary has something up his sleeve when I give him these voltage values.

-bryan

 

[Cloggy]

You might find some useful info here: Electrical generator - Wikipedia, the free encyclopedia
Good luck with your project :thumbup: