Yanmar L 100 Generator voltage drop

[Terry Cooling]

Hi. I have a Yanmar L 100 Generator 4.5 KVA driving a Trace 2.5 KVA inverter/charger, on connecting to the inverter/chager at 220 volts the voltage quite quickly drops to around 195+ volts and the inverter/charger drops out. generator then returns to 220 volts and the cycle starts over again.
Any ideas please, ive tried adjusting the pump timing but if set to the scribe mark genny will not start, so have to off set from the scribe mark.
The only way I can keep the inverter/charger working is to quickly adjust the throttle before it drops out.
Regards Terry.

[wellandpower]

Did this ever work?
or did it just start to fail recently?

[Terry Cooling]

Hi. Yes this was OK for three years with no problem,now as soon as the inverter/charger connects the voltage slowly drops beyond the voltage required for the inverter/charger,I say slowly, maybe over 20 seconds, then when the inverter/charger drops out the voltage returns to 220 volts and the process starts all over again, I have a Gas genny that im using at the moment and all is ok on that one.
Ive replaced the capacitor on the alternator but no change.
Terry.

[merryengineer]

The engine speed is falling at the same time?

[Terry Cooling]

Yes, the engine slows.
Terry.

[Terry Cooling]

HI. Still having problems with this L100, Ive had two mechanics looking at it, latest one today and both say its the alternator, todays one was Catalan, so I struggled to comunicate but he insisted it was the alternator, I disagree and am sure its timing, as when the voltage drops I can over ride it by adjusting the throttle, it will then stay stable and charge.
Does any one know the procedure for timing an L100 AE, IE: flywheel, governor,the manual isnt very clear.
Regards Terry.

[wellandpower]

I think it is almost certain that what you are experiencing is expected and normal.

The fact that your generator is 4.5kVA and the item you are powering is 2.5kVA does not mean everything will work fine. This is not the grid and a generator has limited power.

Making some assumptions:

2500VA @ 0.8pf = 2000w.
Your inverter/charger is 220V, drawing 6 amps (half the current of a 110V model).
The alternator is the smallest one I could find showing a voltage dip.
The unit has an initial inrush totalling 150%.

Applying this load to the alternator, based on the specification sheet I could find.

2500kVA x 150% = 3750kVA.

A charger for an inverter is a non-linear load, so a 20% oversize is required at a minimum.

So the load applied will be 3750kVA, having an effect of at least 4350kVA. Applying 4350kVA to this size of alternator will cause a voltage drop of 15%.

Applying this load to this generator will decrease the engine speed about 10% at a guess, I couldn't find an L100 spec sheet.

A 10% speed drop, could cause another 10%.

So I would expect your voltage to dip by 25% at least, if there is any more load than this best guess estimates, it could be worse. if you are at altitude the engine will perform worse, or if it is over 27Degrees (standard reference conditions), or if you have other loads.

So if you have a 230V unit, your voltage will drop to 165 Amps.

Now you say it is only dropping to 190V, I would therefore say you have got a decent set, or your equipment to measure the voltage is not sensitive enough to see the real voltage drop (are you only relying on an analogue dial somewhere). There could be a number of reasons.

So the answer, you need a bigger generator! This one is never going to do the job, no matter how many engineers visits.

Of course, as you have a diesel, you need to be careful as you don't want to run on low load either )