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LR1 - Generator head scratching

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Jack:
Hello. o7
Seeking wisdom.
I've been given an Lister without any plates for ID. That would be too easy.

It is a LR1 based on the block stamping.
Single pot.
Governor adjusting on the cranking end above and offset to the crank shaft.
3 position fuel lever - start (out and anti clockwise)/run/stop(clockwise)
24 volt started motor with button above starter.

starts first time on an easy crank. starts fine on 24 volts without using the decomp.
no motor issues apart from some light oil leaks.

Generator
This is where I am scratching my head a little.
The wiring was pulled apart for me before I saw it.
The generator is rigidly connected directly to the motor.
It is a brushed generator.
The connection box has 4 wires.

Two heavy gauge wires to the rotor via reasonably heavy slip rings. (4-6 mm2)
Wires to the brushes are red and black.
The rotor is wound more like a stator than a normal rotor, with the wiring through slots.
The resistance of the rotor winding is quite low, in the order of 3-5 ohms (after cleaning and reseating the brushes)
There are no capacitors or diodes on the rotor or stator.

Two lighter lighter wires to the stator (2.5 odd mm2)
Wires to the stator are black and white.
The stator is made up of 4 coils spaced at 90 to each other wired in series. The resistance of the stator is in the order of 200 ohms.

I was expecting the rotor to be the exciter, but am now not sure.
Dispite what I though I new, it appears that the stator may be the exciter (with the coils in series).

The control circuit that came with it had been somewhat butchered. It used current tapping exciter transformer and several capacitors to boost the voltage. It was a mess. I am not going to use it. I am trying to get it running with a AVR I have lying around.

If anyone can comment on the generator it would be appreciated.
Looking for confirmation or otherwise with regards to the stator being the exciter.

cheers, Jack

scott p:
Looks like your rotor is the source of power. I base that on the heavy wires coming off the slip rings.  If so you will get high voltage ac from them or perhaps even DC.

The black and red wires from the brushes are likely part of the exciter circuit. If so probably lower voltage DC.


“The rotor is wound more like a stator than a normal rotor, with the wiring through slots.”

What are you saying there?

Don’t know your expertise concerning this situation so bear with me.

The four stater winding's are also  part of the exciter circuit . Basically electromagnets when charged and the generator is 1800 RPM.

Can’t say much about the control circuit. Looks complicated.It might be a transformer controlled voltage regulator. Could it be a startomatic type of generator?

It may not even be necessary in order to get power from the generator. What does the box on top of the generator tell you?

Can you trace wires from it to the control circuit?

Jack:
Thanks Scott.
I have not tested it yet, but am now confident that it is a stationary field generator.
New to me, this is.
The coils on the stator cannot be anything but poles to cut the rotating armature fields.

I am a Marine Engineer by trade, so my experience is more towards the larger end of power generation. It did not initially occur to me that a stationary field was an option. I guess that the lower currents in a smaller machine allow it.

With the control drawing, switch the field and armature connections. When I drew it I did not even check, as I did not consider a stationary field.
The starter ( S ) is a florescent light starter, presumably to bring the contractor in a little earlier.
The scribble on the exciter line at the bottom of the drawing is a continuous line.
Note the 40 micro farad capacitor. This capacitor was strapped into the box and appears to be an add on. Perhaps added to the circuit when the VR transformer started to fail. I do not like it and cannot but think it would be responsible for some abnormal patterns in the output waveform, particularly as it is after the Bridge Rectifier.

The attached image show the clearly defined stator coils.
It also shows the slotted rotor, as opposed to wire wound coils of a more typical rotor.

Will rewire it and test later today. Southern Australia time.

cheers, Jack

scott p:
Interesting, the drawing is of the current control circuit? When you say rewire, you going to rewire the control circuit or the the rotor.

Sounds like you want to rewire the rotor.  ???

Jack:
Just the control. I already have a couple of generator stators on the bench that need rewording.

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