Onan 5kva generator

DiamondHead

DiamondHead

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Joined
12 Mar 2006
Messages
39
www.powerpoint.com.mt
Hi,
I have onan 5kva in excellent condition, engine runs fine but the genset is giving an output of 190-200v instead of 240v.
Wiring is OK. When I adjust the voltage regulator on front panel, I manage to get 210v. Could this be that engine is running at lower rev than required to pbtain 240v? example could it be a fuel starvation problem? Any ideas will be appreciated.
Regards
Joe
 
I assume this is with no load?

I have to ask. Has anything been changes or touched? Has the fuel system had a problem? Why did you notice the problem? What happened in the previous 1/2 hour?

One cause could be the field circuit breaker. The residual magnetism would be able to generate some output on no load.

If it can be connected to any non-sensitive equipment to load it would help. I mean a light bulb. They are far more stable if you take a bit of power from them.

Do not allow any sensitive electronics like chargers to be connected while it has a problem and you are adjusting the voltage.

As for the speed. Check the filters etc. A poor mans tacho is to set the main engine to 3000 and see if you set up a beat frequency with the generator noise.
 
The generator was last used in october 2006. Since then it was not used. However in the meantime we changed the front oil seal and the fuel pump top cover had to be removed. There are no throttle adjusters inside and nothing has been changed. Underneath this cover there is only a spring that acts as a tensioner to retract the throttle lever, and this spring has no settings.
From my experience, I judge that engine is running much below 3000rev. So I would like to know how to increase the engine revs on this engine. This will be done after I have inspected the fuel system for a good flow of diesel. It could also be a clocked fuel filter.
Thanks
 
There should be 2 levers on the left of the engine. Looking at the belt end. One is the stop and has a solenoid and the other is the throttle. There should be a screw adjuster.

However, that is not the answer. Unless the screw is loose the change of speed is due to another problem. Changing that will just ruin the factory setup.

Get a meter that has a frequency scale measure function and check it is 50Hz on the output.

I would still check that field breaker has not been touched. The little one on the left of the panel with the voltage adjuster.

I would also disconnect the main breaker and run the engine until nice and warm if it has been idle that long.

I assume it is running nice and smoothly and not hiccupping or stuttering?
 
It is a 3000rpm Gen. However I find it strange that revs have changed without a good reason so I do agree this is not the cause. I tried agjusting the voltage regulator on front panel and I get a max 210v, and some lights could work. The engine runs smooth and no hiccups. Could it be a swap wire of the small circuit breaker?..or this controls only the 12v circuit.?
 
Before you do anything you need to check the engine speed is 3000rpm, You can do this with a tacho or a multimeter that read's frequency. you should also make sure the main circuit breaker is open so you a not powering anything in the boat at this time. the engine rpm should be set at 52Hz or 3120rpm with no load. you can adjust the engine speed by the set screws on the injection pump top as per the Onan service manual,
 
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