phases and rotor repair

[scandle]

[h=2]Phases and rotor repair[/h]

Generator is Devilbiss GBV7000 with a B+S 14hp motor.
Problem: The insulator on the rotor broke and the winding came in contact and shorted to rotor shaft. Generator only puts out 120Vac. The shorted winding read 0 ohms to shaft. I unwound the wire repaired insulation and then rewound the rotor winding coil. With the rear cover removed I read 120vac between the green and red wire and also beteween the black and orange wire I have 120vac. So far so good two seperate 120VAC sources. The 2 phases only measure 18-20vac to each other. The 2 diodes on the rotor are good.

Question Is it possible that I wrapped the rotor winding in the wrong direction CW vs CCW?
I did try reversing the diode and with the diode reversed the stator windings read from green to red 10vac and orange to black 10vac. I have since soldered diode back in with original polarity and now am back to 120vac on both stator windings.
It appears as if the two legs of 120vac are in phase with each other thus when one is high the other is also rather then at the low and thus the low reading from phase to phase. Would winding it in opposite direction cause the phase to invert and make the peak to peak voltage read 240? Im really at a loss and just guessing at this point.​

 

[scandle]

rewound

rewound

Ok I wound the rotor winding in a clockwise direction during my repair. The opposite winding is in a counterclockwise direction. I have removed the wire and rewound the coil in a CCW direction. I put some epoxy cement on the wires for security. I will allow a couple of hours drying time and post my results if positive. Otherwise im bailing out. Just exceeds my knowledge level and time.

 

[hardworkingstiff]

I look forward to seeing your results.

 

[scandle]

some results

some results

I started the generator and read 70vac from thr green and red and 70vac between the orange and black. I then reversed the polarity of the dione for the coil in question and now find myself with 120vac between the points above.

Correct me if im wrong
The capacitor creates current in the exciter winding, and when the rotor is spun across the field it causes current flow in the coils on the rotor. The diodes ensures flow in a single direction which establishes the N and S poles. These poles being spun by the engine induce a voltage into the stator windings which output from the generator.
Could I be looking in the wrong place as the problem? Maybe the rotor is just fine and the problem is somewhere else.

Dont forget there are 2 schools of thought with respect to economics.
A Keynesian and the Austrian point of view.
in other words "what your taught" and "what you should be taught" respectively
steve out

 

[GoldDigger]

I do not see any way that changes to the rotor could affect the relative polarity of the two stator windings.
Getting incorrect polarity on half of the rotor might conceivably cause the output frequency to be 30 or 120 Hz instead of 60, with all sorts of associated voltage regulation problems.

Sent from my XT1080 using Tapatalk

 

[scandle]

I think the problem is me

I think the problem is me

Just thinking about this. There is a coil of wire with a diode connecting the ends and when induced by a field generates current and creates a magnet. Lets say with a clockwise winding and diode flow in same direction we get a North and South pole. Reversing the diode causes the S and N pole layout. This expliains the voltage loss with reversing the diode. The results where typical in CW and CCW winding. Reversing the diode places the N/S poles in the same location within the stator and without the opposing forces no current is induced in the windings.

So now I have a winding with 2 seperate 120vac outputs. What I have been doing wrong is trying to measure voltage between these outputs with nothing in common/reference between them. Im feeling a little sick to my stomache and my head hurts.

When I was in the Navy I was taught one of the "assumptions" made in corrective maintenance was "two different components wont fail at the same time giving the same indications"

I always thought the components they were talking didn't include me. I better check the wiring harness plugs etc before all my hair falls out

wish me luck
steve out

 

[scandle]

I do not see any way that changes to the rotor could affect the relative polarity of the two stator windings.
Getting incorrect polarity on half of the rotor might conceivably cause the output frequency to be 30 or 120 Hz instead of 60, with all sorts of associated voltage regulation problems.

Sent from my XT1080 using Tapatalk

I have always wondered about the frequency. The generator directly coupled to a shaft spinning 3600 rpms with a single N/S pole. I might be crazy but what I see happening is electrons being pushed and pulled. The farther they move the higher the voltage, a sine wave. Correct? Where I get lost or confused is if im looking at this with an oscilloscope I would see a frequency 3600hz with a single magnet. This is what I seeing in my head I single cycle of a sine wave for each rotation.
What how why where

 

[gar]

131212-2027 EST

scandle:

3600 RPM is 60 revolutions per second, and therefore, for a 2 pole alternator the output frequency is 60 Hz.

Also see http://en.wikipedia.org/wiki/Alternator

A V-8 4 cycle internal combustion engine has a spark pulse rate of 400 Hz at 6000 RPM. Thus, the ignition coil in a single coil engine has to produce a spark 400 times per second. This is derived from (6000/60)*(8/2).

Ford won the famous patent case brought by Seldon against Ford because Seldon's patent claimed a 2 cycle engine and Ford cars used a 4 cycle engine. This should never have gone to trial.

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