Dead Stator...RM Stator

[tom203]

Dead simple technology? ok, Why don't you show this shop the size of these stators and see how excited they get about rewinding it. These stators are tiny compared to what most shops work on.
I wonder where most of this wire is being made now ? probably the far east where standards have a way of being loosely adhered to.
But you bring up a point about oil that concerned me. When I did my stator (gs 650 ), I was surprised at lack of oil and oil stains inside rotor cavity. Later after putting it back together, I used a level to determine that maximum oil level would just touch rotor bottom- running would be less. Splashing oil would be nice, but stator is nested inside rotor, so I have my doubts about cooling oil even ignoring oil is 200 degrees. Most cooling comes from stator cover- maybe we should add cooling fins.

[bluewool]

200F is not warm.

I did show them the core of mine. He knew what it was right away. Even one of the outside sales guys knew what it was. They had no trouble rewinding these for years until it became unprofitable to deal with off shore imports. The old guy actually showed me where the "automotive division" used to be, it was a 1/4 of the 20000square feet. These are the simplest windings, this is the sort of thing they use to get 1st year apprentices to wind.
My comment about the "cooling" was this... people think that 200F is hot. It is not. Not when it comes to the temperatures the internals of alternators/generators, or electric motor sustain. I am not under the illusion that somehow a semi enclosed stator sitting in a half full sump is "oil cooled" 200F oil coming in contact with a 300F windings could have no effect other than to cool it.
No need for cooling fins just a series r/r.

[bluewool]

oh, and he said he would rewind it. 3hr @ 100/hr(standard shop rate). 1 week turn around(because all the apprentices were at BCIT). Obviously I declined.

[posplayr]

I am not under the illusion that somehow a semi enclosed stator sitting in a half full sump is "oil cooled" 200F oil coming in contact with a 300F windings could have no effect other than to cool it.
.

Why only 300 DegF, Did you ask what temp it takes to discolor the powder coating?

It takes close to 400 DegF just to get the PC to flow and cure

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

Curing
When a thermoset powder is exposed to elevated temperature, it begins to melt, flows out, and then chemically reacts to form a higher molecular weight polymer in a network-like structure. This cure process, called crosslinking, requires a certain degree of temperature for a certain length of time in order to reach full cure and establish the full film properties for which the material was designed. Normally the powders cure at 200°C (390°F) in 10 minutes. The curing schedule could vary according to the manufacturer's specifications.
The application of energy to the product to be cured can be accomplished by convection cure ovens or infrared cure ovens.

[Nessism]

Why only 300 DegF, Did you ask what temp it takes to discolor the powder coating?

It takes close to 400 DegF just to get the PC to flow and cure

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

How do you know that blue stuff is power coat? And if it is, how do you know it cures at 400F? There are various grades and types of powder.

[posplayr]

How do you know that blue stuff is power coat? And if it is, how do you know it cures at 400F? There are various grades and types of powder.

Because it takes over 500 degrees to make $hit burn

And our resident expert on stator rewindings suggested that is what it is (Matchless)

Ed, I think you will find in YOUR research that thermal epoxies cure right in this temperature range.


I think I hear quacking and something waddling around .................wonder what it might be

[bluewool]

I was using 300F(150C) because it's the low side of internal temperatures for alternators/motors. No specifics on the particular GS winding.
If yours are running 400-500F that's a ton of extra heat!! That's much hotter than I would have expected any sane person to design!! have you ever checked the temperature of the side case after a long fast run? it would be interesting. I will try to at some point.

[posplayr]

I was using 300F(150C) because it's the low side of internal temperatures for alternators/motors. No specifics on the particular GS winding.
If yours are running 400-500F that's a ton of extra heat!! That's much hotter than I would have expected any sane person to design!! have you ever checked the temperature of the side case after a long fast run? it would be interesting. I will try to at some point.

with the hand at least it is very hot using SHUNT R/R.

I think the power disappation requirements for the stators are: "out of sight out of mind."

[tom203]

with the hand at least it is very hot using SHUNT R/R.

I think the power disappation requirements for the stators are: "out of sight out of mind."

When my stator failed (short to ground ), out of curiosity the next day I started it up. Within 1 minute the stator cover was VERY hot as the short circuited windings had their fun.
I'm still absorbing the Compufire info, but my initial impression is that it was originally designed to boost output at low rpm on behemoths , but it's ability to open circuit stator output seems interesting. But when all is said and done, the stator has to pump out 150 (?) watts just to keep up with power needs.

[posplayr]

I was using 300F(150C) because it's the low side of internal temperatures for alternators/motors. No specifics on the particular GS winding.
If yours are running 400-500F that's a ton of extra heat!! That's much hotter than I would have expected any sane person to design!! have you ever checked the temperature of the side case after a long fast run? it would be interesting. I will try to at some point.

It just occured to me that at some point while I still had the FET R/R installed I held a thermocouple a different spots on the engine*just by han d so not very accurate). It may have been after a ride or after doing those current measurments but the stator cover was at least as hot as the head measured near the combustion chambers.

[posplayr]

When my stator failed (short to ground ), out of curiosity the next day I started it up. Within 1 minute the stator cover was VERY hot as the short circuited windings had their fun.
I'm still absorbing the Compufire info, but my initial impression is that it was originally designed to boost output at low rpm on behemoths , but it's ability to open circuit stator output seems interesting. But when all is said and done, the stator has to pump out 150 (?) watts just to keep up with power needs.

without knowing where it shorted hard to conclude much but say voltage has dropped. Short to ground short to winding??

The need to get high current/voltage at low RPM drove the design to become more efficent that is correct.

I dont really understand your last statement. I provided a simplified explaination of the SERIES v.s. SHUNT operations which show the current and stator power disappation of both.

http://www.posplayr.100megsfree3.com/FH012AA_Charging/RR_Tutorial.pdf

when using a SHUNT R/R the stator has to carry almost twice as much current as when running the SERIES R/R

[tom203]

My dead stator still showed .9 ohm between any two phases.I cut the wye connection and found that two phases were shorted to ground. I measured wire size at .040 inch- probably 20 gauge figuring something for insulation.
As for Compufire, I did ponder your link, but I think it's a little misleading.When the series r/r is in regulating phase, I think it is switching stator current flow on/off mucho times a second to limit effective maximum current- if it just open circuited it, there would be no power from stator. This is a good idea as you don't need 25 amps running thru it as could happen with shunt r/r dump.
The problem seems to be that to get decent output at low rpm, you have too much at high rpm. The Compufire idea makes sense.

[posplayr]

As for Compufire, I did ponder your link, but I think it's a little misleading.When the series r/r is in regulating phase, I think it is switching stator current flow on/off mucho times a second to limit effective maximum current- if it just open circuited it, there would be no power from stator. .

sorry to mislead with providing cycle by cycle voltage and current waveforms

[Darkstang]

Ok, back from a weekend of camping and doing NOTHING...

WHERE can I get one of those fancy compufire r/r? I can find the 32 amp one but not the 40. Dennis Kirk is out of stock.

On the heat issue, I will take pic with my thermal camera when I get it running... my job is running Vibration Analysis and Thermal Imaging routes and an Alltrade Mechanic for a large paper plant.

I have an associate degree in electronics and one of the pet projects i designed years ago with my old boss for our personal use was a circuit to run axuillary lighting for our 4x4's that ran the lights off a 12vdc square wave. We could run about a 75% duty cycle before the light out put got dimmer. Fillament would cool down any shorter.

I got out of the surface mount and Electronics Design aspect a long time ago. I am more at home with large AC and DC drives, motors and PLC's.


Ken

[tom203]

sorry to mislead with providing cycle by cycle voltage and current waveforms

Golly, those diagrams and graphs are sure pretty, and show that it works but how about the hows and whys? I hope it's not magic , cuz my faith in science is already strained.