gnerator output

[Andyloc]

I have a bult in 18w farymann generator which i know has provided 240v ac in the past. i have reconditioned the engine and all is working fine. i have not touched the generator head as my knowledge is limited. when i started the generator the output from the head was 25v ac. alot of old wiring and untits have been removed from the boat since purchase and in the output supply cable from the genset was an old grey metallic box with a 240 v 3 pin socket which had been water damaged and had lost all markings so it was disposed of. could this have been a step up transformer or is it likely that the generator head is past it. if so any ideas where a new one can be sourced from.

Andy

 

[stuhaynes]

I have a bult in 18w farymann generator which i know has provided 240v ac in the past. i have reconditioned the engine and all is working fine. i have not touched the generator head as my knowledge is limited. when i started the generator the output from the head was 25v ac. alot of old wiring and untits have been removed from the boat since purchase and in the output supply cable from the genset was an old grey metallic box with a 240 v 3 pin socket which had been water damaged and had lost all markings so it was disposed of. could this have been a step up transformer or is it likely that the generator head is past it. if so any ideas where a new one can be sourced from.

Andy

Not an expert Andy, but you must be careful. As I understand it the AC generator is dependent on the speed of the engine to maintain 50Hz. With the wrong setting you could blow your electrical equipment. There are some proper experts here, so I would wait for one of them before you connect the genny to anything.

 

[Andyloc]

thanks for the advice the output supply is isolated from the rest of the boat until the problems solved

Andy

 

[david_bagshaw]

smaller sets often have excitation capacitors, which are quite large and easily damaged, and there is little or no output when missing.

 

[William_H]

Generator

Assuming this is a 240v gen set then (18W) more likely means 1800w being around 3 to 4 horsepower.
The generator will have a rotating field coil which must be fed with DC to provide a magnetic field. This DC will probably be fed from the AC output via rectifier and a regulator of some sort. The regulator will sample the AC output voltage and if it is low provide more dc to the field coil or reduce it if AC volts are high. This may be done by a voltage sensitive coil compressing a carbon pile or far better electronically with transistor.
I can't imagine how old the set is.
The engine should have a governor to hold the engine precisely at 1500 RPM (or 3000 Rpm)
It is unlikely that the box you removed had a transformer in it to step up the voltage although this is possible if it really is only 18w output. Not much use for anything. The box may have however contained the excitation circuit and regulator. (for the field coil)
The AC most likely will come from the stator outside windings at 240V.
So I would suggest remove the generator to an electrical shop along with all the related boxes and components in the hope they can sort it out.
Or give model number etc and hope someone knows something about it. good luck olewill

 

[Andyloc]

thanks for the input iv taken anotherlook at the engine block and its stamped 4.7KW 6.4 Hp.