Dayton 4lm38b with generac rotor/stator no power output

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mjr46
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So i have a 20kw dayton generator whole home set up with a generac power unit(stator/rotor) this thing has been down for almost 2 years, no one near me will service it. last summer i fired it up and noticed the ac voltage gauge registered 0 ish and the frequency was past 65/off the meter reading......and noticed the dc meter would read 12v/not charging.....i also would notice a chirp noise from the stator area then the hertz meter would go back to 60ish/normal and the dc voltmeter would read 14v/ charging, this cycle continues for a minute or 2 until the generator shuts off and red fault light lites up.....also i notice is sequence with the chirp from the power unit the red led lights briefly on the voltage regulator then goes out when the chip happens and it continues to do this cycle until the generator shuts off after a minute or two......all the while no voltage output..........now fast forward to last night/1 year later= i had not started the generator in at least 8 months.....for giggles i said awwww heck, powers out and i know the generator is broke but maybe it has fixed itself by sitting..lol ....yeah right......to my surprise i fired it up and boom.....it had voltage and frequency looked good, so i threw the transfer switch and what do you know ......let there be light.....for 10 minutes it worked fine then i noticed the garage lights got brighter than normal for a few seconds then really dim then off = no power, generator continued to run for a minute while i heard the chirping coming and going then generator cuts off and fault light on....went back tonight to test it and no voltage output....and the chirping and led on the voltage reg comes and goes in accordance with the chirp from the rotor/stator. i checked the brushes, they looked good....i also tested voltage at the 90 amp main breaker and before the chirp it is 15 volts, after the chirp it goes to 19 volts and continues to do such until the generator shuts off......i also tested the field breaker = tested okay.............does this sound like a bad voltage regulator? i need to get this fixed it's been 2 years and no worky!! any help is appreciated and what and how should i test anything else??
mjr46
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guys this generator runs on liquid propane if you need to know and i saw another thread and mine is doing exactly what his is, only mine registers frequency but nothing else and my control panel area looks just like his only my motor is a mitubishi 1.5 liter not fiat...... here is his thread:

viewtopic.php?f=7&t=577
Chris
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I would start with a rotor resistance test. The center 2 wires on the AVR should be removed and measured for resistance with a good digital meter.
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mjr46
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Chris wrote:
Fri Jan 24, 2020 8:13 pm
I would start with a rotor resistance test. The center 2 wires on the AVR should be removed and measured for resistance with a good digital meter.
so if i go inline from top to bottom that'd be 3 and 4 pin? also i have a blue point dvom.....it by no means is a cheapy , what spec /ohm should i be looking for?
Chris
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Those rotors are normally in the 10 ohm range if I recall correctly.

Yes, pins 3 and 4, but you're measuring the wires removed from the regulator, not still attached.
Generac tech for over 12 years. I'm here to help!
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mjr46
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Chris wrote:
Sat Jan 25, 2020 9:07 am
Those rotors are normally in the 10 ohm range if I recall correctly.

Yes, pins 3 and 4, but you're measuring the wires removed from the regulator, not still attached.
thanks, i'll do it today and report back!! :)
mjr46
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Chris wrote:
Sat Jan 25, 2020 9:07 am
Those rotors are normally in the 10 ohm range if I recall correctly.

Yes, pins 3 and 4, but you're measuring the wires removed from the regulator, not still attached.
so my wife ran off with my car today and in the car was my good meter...so i had to use a small craftsman 82141 dvom i have and set to the 20k ohm scale it read .04 kohm which is 40ohms so where do i go from here??
tbonini
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That indicates that you have dirty slip rings that will need to be cleaned. I would order a new brush set as well as they will need to be removed to get to the slip rings and getting to them is a lot of work so if you are performing the tear down anyway, it makes sense to just replace them since they will be worn and are rather cheep as far as parts go.
mjr46
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tbonini wrote:
Sat Jan 25, 2020 4:06 pm
That indicates that you have dirty slip rings that will need to be cleaned. I would order a new brush set as well as they will need to be removed to get to the slip rings and getting to them is a lot of work so if you are performing the tear down anyway, it makes sense to just replace them since they will be worn and are rather cheep as far as parts go.
the brushes are easy to get to on this unit......i've already had the brushes off and looked at them.....they are not that worn and have plenty of tension and the slip ring surface is easy to see.....how does one clean the slip rings?
tbonini
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I guess that your Gen is different from mine because I don't remember being able to see the slip rings until I removed the rear bearing carrier and then they were fully exposed. To clean mine I sprayed them with electrical contact cleaner and then removed any stubborn spots with crocus cloth. If you can see yours, what do they look like? They should be copper colored and somewhat shiny. If they are copper colored and dull they are probably ok but if they are black like mine were, then they need to be cleaned.
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