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150 VAC with generator per leg


Wrknrvr

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 Customer called yesterday with this reading of 159 vac on both legs of power on a 15000 watt Kabota generator.

 

 I will be there on Monday an to take a look at it. The blower fan that cools the generator by blowing air across the generator end and then over the engine and then over the radiator to cool it , is bad. Customer will have a new ac fan blower motor to install Monday am, but I think there is ore wrong with this unit.

 I will need service documents for the unit. I should be able to find them online.

 

 Any thoughts on this subject,.   Thanks,,.    Vern

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Possible voltage regulator, or meter issue. What kind of meter is being used to measure 159 volts? If it's a peak voltage meter, my calculator tells me that translates to 112 RMS  volts. I'm probably overguessing this, and it'll be the regulator. 

I have been wrong before, I'll probably be wrong again. 

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If the voltage reading is accurate, he definitely has a voltage regulation problem. Either of the other posts could be right if the cooling fan is motor driven. That said, cheap meters don't normally read peak voltage but rather average voltage. If measured as average voltage the 120V RMS voltage would be average of 132V. 

  • Vp x .707 = Vrms
  • Vrms = 1.11 x Vavg
  • 1.414 x Vrms= Vp
  • Vavg= .637 x Vp

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

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Before condemning the voltage regulator, check the frequency of the generator, i.e. the RPM of the engine.  If it's running fast many generators will give high output voltage even with a working regulator.

If you don't have a frequency meter a $20 Kill-A-Watt power meter plugged into an outlet works well.

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 Well I went to the job today and the new fan motor will not be delivered till tomorrow.

 

 But I checked the voltage on the coach meter. It is at 150  volts. So I tried to pull the seliniod operated govoner done to slow the generator down. Really hard to pull back. Then clunk, o shiiiiiit.  Dame thing shut off. Now it will not try to start or do anything.

 

 It blew a 10 amp fuse. Repaced the fuse and now it starts. But 150 volts.

 

 Well just for fun I watered the grass and drank beer tonight.

 

 Be back to gen on Wednesday .

 

 Sometimes,.   Vern

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9 minutes ago, Wrknrvr said:

Maybe I will just water the grass,.

I haven't ever worked on a Newell, only drooled over them! Now you have found something that I could help you with, especially if you supply the beer.  😁

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure

            images?q=tbn:ANd9GcQqFswi_bvvojaMvanTWAI

 

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 The customer stoped at a Cat power eguipment shop. They took a quick look. They did not really do anything. I picked up the blower motor the customer ordered at the campground where I first looked at the gent. I was there for another job.

 I told him where I could meet him along the road. They sent the wrong motor. So we started it without a blower motor in the system. Still had over voltage. As I thought it would.

 Customer did not really trust what I was saying about the throttle not floating at the proper rpm for proper voltage. He was talking to someone a Newel that was not on the same page as for how the Rpms are regulated.

 

 The throttle linkage was pulled tight in the open position when the switch was turned on. Ok so then when it starts I really think it should find its rpm and then regulate throttle as power is needed. But it just keeps the throttle pulled wide open.

 

 Customer was flying out on Saturday. And be back in two months. He was going to find someone in Missoula Mt to fix it while he is gone.

 

 

 I will try to get back later with what was wrong.

 

 I am on vacation,.   Vern

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12 hours ago, Wrknrvr said:

The throttle linkage was pulled tight in the open position when the switch was turned on. Ok so then when it starts I really think it should find its rpm and then regulate throttle as power is needed. But it just keeps the throttle pulled wide open.

 

That may not be a throttle as such, even though it would connect to the gas pedal if the engine was driving a motorhome.  As it's opened and closed, it changes the RPM setting of the mechanical governor inside the injection pump, which in turn regulates the fuel delivery until the engine speed matches that RPM. 

I don't have any Kubota experience but I managed several commercial generators with Cummins, White (remember them?) and Caterpillar engines.  They had that arm locked in a fixed position that gave 1800 RPM (60 Hz) under no load and the governor inside the pump kept the engine at that speed as the load changed.

Sounds like something may have happened inside the injection pump that shifted the set point or disabled the governor. 

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  I am on vacation so I will get back with how a Onab diesel generator regulates power. I just thought that I do have a service document on it in my vehicle.

 

 Now someone may want to look it up on Nonan page that I know Kirk has.

 

 I am going fishing.    Then my DW and me are going to the RedAnts Pants country festival at White Sulpher Springs Montana

 

 

 

 will check in on Monday ,.   Vern

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 I think Lou is on to the problem with an internal governor. Just did some research and I learnred something new. Apparently they do have a weight operated governor internal to the injection pump.

 The throttle is connected to injection pump on this unit. When switched on it just pulls the throttle to a set, adjustable setting. Then the weights in the governor assembly controls speed. Which would control voltage.

 

 I really thought the weight governor idea was back in the Steam  engine time.

 The customer is gone for now. Will return in set ember to pick his RV up. He was going to find someone in Missoula Mt to work on it.

 

   There probable is a broken weight spring broken in the governor system.

 Learned something new this week,.    Vern

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  • 2 weeks later...

What you are seeing as a throttle may be an air shut off, instead.  Diesels usually run with an unobstructed air intake path with the speed being controled by the fuel pump which probably has an internal governor. Diesels can be shut down, primarily, in 2 ways: 1- cut off the fuel or  2- cut off the air, or perhaps by cutting both.  Cutting off the fuel may not always work...a diesel can run away because of a turbo bearing leaking oil into the intake system or because of flamable fumes being sucked into intake.  Cutting off the air always will shut a diesel down...IF you can cut off the air. i have seen all sorts of things used to cut the air to a run away diesel: a built in air valve, a welding blanket, pillow, shirt...the list goes on. If a diesel is running away, anything you can lay your hands on,looks like something that may stop or slow the air flow before the engine grenades.  It will be interesting to see what is causing the 150 volts you are seeing.    Charlie

Don't ever tell a soldier that he doesn't understand the cost of war.

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 I will talk to the customer when he returns to Montana . But I did say to him to find a deisel shop to fix it. If it was mine I would fix it.

 

 But I leave in the fall for the south and he will be back in California.

 

 So when there are odd things I just pass on it. Yesterday I had a call about a Onan deisel that was hard to start. He is leaving in a day or two. He can get home without it. 

 

 And I am behind by adopt 8 jobs at this time.

 

 I will respond when I talk to him.

 

 Thanks,.   Vern

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