I have a Kubota generator that runs great but has no output. I opened the generator end cap and found some burned area of the voltage regulator. I was able to find an aftermarket part and installed it but still no output. I tried the re-engergizing trick with another battery and the idle picked up and voltmeter went slightly negative. Any help would be appreciated.
AVR6500-B runs but no output
- Thread starter montvaleplace
- Start date
This is a tractor forum, but what the heck.
Does the generator have brushes or does it use a capacitor?
Check the circuit breakers with a VOM. Gen not running of course.
Next ohm from neutral in a receptacle to its hot. Do this with gen off. Take the leads on the VOM, put one in the receptacle and the other in the same receptacle. You should measure 0.01 ohms. This will check from the receptacle thru the windings.
If the gen has brushes, carefully loosen the brush assy and take it off - don't let the springs behind the brushes fly out. Visually check the brushes and ring.
If capacitor, check the capacitor with a meter to see if it is working.
Report back with what you find, and we'll try from there.
By the way, don't flash it again.
Does the generator have brushes or does it use a capacitor?
Check the circuit breakers with a VOM. Gen not running of course.
Next ohm from neutral in a receptacle to its hot. Do this with gen off. Take the leads on the VOM, put one in the receptacle and the other in the same receptacle. You should measure 0.01 ohms. This will check from the receptacle thru the windings.
If the gen has brushes, carefully loosen the brush assy and take it off - don't let the springs behind the brushes fly out. Visually check the brushes and ring.
If capacitor, check the capacitor with a meter to see if it is working.
Report back with what you find, and we'll try from there.
By the way, don't flash it again.
Welcome to the forum from Alabama. I really like your area especially in the fall when the trees turn. I used to arrange to go to training at Data General at that time of the year.
Thanks for the response, I checked resistance between neutral and hot and the meter reads 0. The unit does use brushes which look ok, and the slip rings look ok also. I read the resistance at the brush terminals through the brushes and armature windings and got 82 ohms. with the motor running It reads about 35volts a/c at the 110 outlets. I have tried to find some schematics and service manuals but it seems next to impossible to access. If you know how to find that info I could really use it.
I don't have any docs for your particular gen. Best I can do is walk-thru for a generic gen.
The output frequency needs to be checked. If you don't have a meter, then check at the big box stores for a "KILLAWatt" which will plug into a standard 120VAC receptacle and read out Hz. Idle freq should be 62 to 62.5 Hz.
With gen off. There should be 2 main stator windings and one excitation winding. With the cover off, see if there are conductors going to a terminal block or the like. Disconnect and isolate these wires. Now check if any of these are grounded - they should not be. The excitation pair may not be on the terminal block but on a separate connector. They will be headed for the AVR.
Another check. With the gen running, measure the voltage for Line1 L1 and Line2 L2. Are they both 35VAC?
The Automatic Voltage Regulator (AVR) should be adjustable. You may have to open it to find the adjust. Is it accessible? Please resist the temptation to crank on it before the other checks.
Let us know what you find.
The output frequency needs to be checked. If you don't have a meter, then check at the big box stores for a "KILLAWatt" which will plug into a standard 120VAC receptacle and read out Hz. Idle freq should be 62 to 62.5 Hz.
With gen off. There should be 2 main stator windings and one excitation winding. With the cover off, see if there are conductors going to a terminal block or the like. Disconnect and isolate these wires. Now check if any of these are grounded - they should not be. The excitation pair may not be on the terminal block but on a separate connector. They will be headed for the AVR.
Another check. With the gen running, measure the voltage for Line1 L1 and Line2 L2. Are they both 35VAC?
The Automatic Voltage Regulator (AVR) should be adjustable. You may have to open it to find the adjust. Is it accessible? Please resist the temptation to crank on it before the other checks.
Let us know what you find.
The workshop manual for my Honda unit has this simple test which should work on any brush type generator.
Disconnect any wires to the brushes and then apply 12 volt 12 from a battery to the brushes which by passes all the controls which can be suspect. Unit should produce 60 to 70 volts AC which then shows that the voltage regulation stuff is no good. If you get no output then unit is likely scrap.
Dave M7040
Disconnect any wires to the brushes and then apply 12 volt 12 from a battery to the brushes which by passes all the controls which can be suspect. Unit should produce 60 to 70 volts AC which then shows that the voltage regulation stuff is no good. If you get no output then unit is likely scrap.
Dave M7040
If you are getting ac voltage at the 110 outlet, it could be as simple as increasing engine speed until you get 110.
Hi Jim L. with the gen running there is 35v a/c at each 110v outlet. I wrote the wrong resistance value in the above post about the brushes and armature, it reads 57 ohms not 82. I have not checked the stator windings yet but I will and get back to you. On the terminal block there are 8 wires, 4 that go into the stator and 4 that go up into the control panel on the front of the gen. Am I supposed to put an ohm meter from each stator wire to the gen case or am I going across stator wires? The excitation wiring I'm not sure of, there is a 4 wire harness that comes out of the regulator and goes into the stator. Is that where I'm checking for ground also? I read in another posting that the armature and brushes should read between 55 and 60 ohms, so they seem ok.
Hi Dave-eng, I tried the test you suggested also and with 12v going into the brushes and gen running there was .6v at the outlets.
You want to isolate the two stator main windings. So the 4 wires going to the stator are the ones you want. One test lead to each stator wire in turn. The other test lead to ground. You're checking to see if either stator winding is shorting to ground - if it is that's a problem.
Same with the excitation winding. It is probably in the 4-wire harness from AVR to stator. Likely it would be two wires with the same color code. If you can't determine the excitation winding, then go ahead and check all 4. Again, you're checking if the wire(s) is shorted to ground. So you are checking the stator side of the connectors.
Same with the excitation winding. It is probably in the 4-wire harness from AVR to stator. Likely it would be two wires with the same color code. If you can't determine the excitation winding, then go ahead and check all 4. Again, you're checking if the wire(s) is shorted to ground. So you are checking the stator side of the connectors.
I will have to test the stator wires tomorrow, but I did notice that where the original regulator was there is blackened area on the front of the stator that I assumed was just from the regulator burning out. I hope the stator isn't melted.