Understanding my generator

[bluegreencanal]

I have a generator which is working below par and I have had it maintained to some extent but have not managed to get it back up to par.

 

There is a box to one side of it which sits below the water intake before it gets to after it goes through the generator. It has big 2 or 3" jubilee clipped pipework and I would have guessed it was a mudbox or silencer but wanted to know should I ever take a look inside and empty it etc. I have noticed oil on the floor there, but the oil levels in the generator are stable (checked and topped monthly).

 

What is not good, is that it is not putting out quite what it used to and I wondered if it needed some internal electrical work to the bushes etc...

 

Any help received gratefully. Thanks in anticipation and Happy Christmas!

 

Sue

[Chris Pink]

More info please Sue

 

Make and model?

 

'not putting out what it used to' what do you mean and how are you measuring it?

 

The cooling side would be good to understand more from safety )from sinking) than performance. Photo?

Edited December 22, 2011 by Chris Pink

[alan_fincher]

Make and model?

"Mase marine 5.7kW generator IS 6.5" possibly ?

[Chris Pink]

"Mase marine 5.7kW generator IS 6.5" possibly ?

 

Still simmering Alan? I can't see subheadings on my phone.

 

So I apologise unreservedly for my incompetent stupidity.

[by'eck]

Marine AC generators usually have brushless alternators so no maintenance possible there. The only maintenance is usually to the engine. If the engine is overheating then yes investigate the cooling system. Heat exchangers (if indirectly cooled) are a major source of cooling problems & need to be regularly cleaned every couple of years.

 

Not sure what you mean by not putting out quite what it used to - are you saying the AC mains voltage it gives is below 240 volts? or maybe that it stalls with a load less than its maximum?

 

If the volts are low this is usually controlled by a capacitor. I had one fail which ceased all AC output. Putting in a slightly higher value replacement gave me a few more volts, on light loads at least.

[Robbo]

There is a box to one side of it which sits below the water intake before it gets to after it goes through the generator. It has big 2 or 3" jubilee clipped pipework and I would have guessed it was a mudbox or silencer but wanted to know should I ever take a look inside and empty it etc. I have noticed oil on the floor there, but the oil levels in the generator are stable (checked and topped monthly).

 

Sounds like a wet exhaust system like....

 

 

or

 

Edited December 22, 2011 by Robbo

[alan_fincher]

Still simmering Alan? I can't see subheadings on my phone.

 

So I apologise unreservedly for my incompetent stupidity.

Well it gave you the answer to your question.

 

I apologise for not knowing in advance the limitations of you browsing the forum on your phone!

[by'eck]

There is a box to one side of it which sits below the water intake before it gets to after it goes through the generator. It has big 2 or 3" jubilee clipped pipework and I would have guessed it was a mudbox or silencer but wanted to know should I ever take a look inside and empty it etc. I have noticed oil on the floor there, but the oil levels in the generator are stable (checked and topped monthly).

 

Sounds like the item you describe is the GRP lift silencer or muffler as shown in Robbo's post. They can be made out of GRP, stainless or heat resistant plastic. Their main purpose is to provide a trap to stop the cooling water left in the exhaust system from pouring back into the engine when its stopped. Any silencing effect is a secondary function. Generally these devices are maintenance free although you may find a drain hole at the lowest point to allow flushing out.

 

The water separator is an optional addition to make for (marginally) quieter running by allowing the cooling water to drop back near or below the water line rather than splashing out of the necessarily higher exhaust outlet.

 

Still waiting to hear a fuller explanation of why you think its not performing as it did.

 

BTW have confirmed that your particular generator does have a brushless alternator & an indirectly cooled (wet exhaust) engine.

Edited December 22, 2011 by richardhula

[bluegreencanal]

Sounds like the item you describe is the GRP lift silencer or muffler as shown in Robbo's post. They can be made out of GRP, stainless or heat resistant plastic. Their main purpose is to provide a trap to stop the cooling water left in the exhaust system from pouring back into the engine when its stopped. Any silencing effect is a secondary function. Generally these devices are maintenance free although you may find a drain hole at the lowest point to allow flushing out.

 

The water separator is an optional addition to make for (marginally) quieter running by allowing the cooling water to drop back near or below the water line rather than splashing out of the necessarily higher exhaust outlet.

 

Still waiting to hear a fuller explanation of why you think its not performing as it did.

 

BTW have confirmed that your particular generator does have a brushless alternator & an indirectly cooled (wet exhaust) engine.

 

Hi everyone, thank you very much for all your helpful replies. They are making me think it through abit.

 

Yes, it is not putting out 240 anymore, it manages about 190 even when it is cool and newly switched on for the day. It used to run the fridge reasonably and the hoover at the same time...now it wont run the toaster (new item) so I have to switch it to inverter to make toast...

 

It does a very reasonable job of charging up batteries but if I run it for more than two hours (say the batteries have gone quite low)the charge drops very low even if the batteries have not finished charging.

 

It will start off around 45 amps and drop as low as 2 or 3.

 

It had some maintencance recently where the engineer tried to adjust it get the best out of it,

 

Cooling, it had a new radiator last year or year before. Not sure what I should clean every two years...am not very familiar with inner workings which are of an electrical nature, quite good with the basic end of things like changing the impeller, changing the oil, clearing out blockages in teh water flow etc.

 

The box thing, sounds like it is the GRPthing which stops water going back into the engine. It doesnt look exactly like the nice drawing sent to me (thank you) I reckon it might be a bit grubby in there after a few years of no maintenance tho so will have a look at it soon!

 

Sorry I didnt reply sooner, I dont expect immediate responses and am always thrilled to get some, but ususally wait a while to see what comes in...but I really do appreciate it. I have always managed to get to the bottom of it after everyone has given me ideas. Big thanks will post again when looked more closely...

[by'eck]

Unless the engine is running at lower than normal speed (should be 1500 rpm on IS 6.5 to give 50Hz) I would suggest replacing the capacitor as mentioned above.

 

Try same value one first & make sure its same spec as original.

Edited December 28, 2011 by richardhula

[bluegreencanal]

Thank you Richard! I will try this.

Seasons greetings!!

Sue

[Arthur Brown]

Having a brushless alternator that malfunctions, I turned to this thread in hope, but something appears incomplete. There is mention of Capacitors but no reference to where the capacitor(s) can be found or the cct in which they operate. Can anyone share the details please.

[Chalky]

I used to work on aerospace brushless alternators about 20 years ago. The designs used then had 2 coils on the rotor with rectifier diodes between them. Failure of these diodes would cause a drop in output. Not sure if that design is used in marine machines - they weren't cheep to produce.

[by'eck]

Having a brushless alternator that malfunctions, I turned to this thread in hope, but something appears incomplete. There is mention of Capacitors but no reference to where the capacitor(s) can be found or the cct in which they operate. Can anyone share the details please.

 

The capacitor electrically sits across a dedicated excitation winding adjacent to the main stator. The capacitor itself is usually located external to the alternator casing in a user friendly position to allow easy replacement.

 

This is the best description I have found of its working:

 

The capacitor is a common method of voltage regulation on smaller, less expensive generators. Coleman and many others use them - it's a common method on European generator ends. The capacitor stores a charge which balances a winding at the output voltage. If the output voltage goes down, power flows from the capacitor increasing excitation, and if the voltage goes high, the capacitor stores excitation, causing the voltage to drop until they are in balance again. Very simple system, no brushes to wear out, no expensive voltage regulator needed. Works well. If the voltage is too high or low, check the capacitor.

Edited December 31, 2011 by richardhula