Generator info sought

Kim,

I stand corrected but the sliprings are the AC side of things but it may need exciting to get it going hence the other armature. You dont have to connect a battery to give it a kick. Or is it a Dynostart ?

Mart> I picked up a generator yesterday evening. It is close coupled to a

Well, I wondered that Martin. Unusually, there is a control knob on the panel to increase the output which is not something I've noticed before on an alternator - but there, aside from a few automotive devices I've fiddled with, I've not had anything to do with brushed alternators.

Word has it that in a previous life, the generator bit supplied the current for much of a house. Redundant from this task, the generator has been pressed into further service & close coupled to the Clinton engine in the recent past. Everything about it is massive, the engine looking somewhat whoosy against the backdrop of Brunel-style engineering that surrounds it. The bed is of steel girders of a specification that would please even Peter Forbes ;o)) and it has two wheels and a handle to wheel it about. It is just about the most over engineered thing I've ever seen to supply 1kva and I wonder if it might not be just the thing for a Larger Engine.

Anyone interested?

In message , Kim Siddorn writes

I have only just now had the chance to look at your pictures, Kim. BKB are (or were a couple of years ago) still going, it transpires.

STS Electric Motors Ltd BKB/EPE, Doulton Road, Cradley Heath, Warley, West Midlands B64 5QB, UK Tel +44 (0)1384 567755 Fax +44 (0)1384 567710

Ken Stephenson is the man to ask for and is a most helpful man in relation to older equipment. He sent me spec data on a 1970's BKB generator.

They are 'trade-only' so you might like to represent yourself as the representative of a corporation rather than a private individual...

I'm tempted to agree with Martin on the commutator - a source of DC for excitation?

TTFN

Pete

You might want to keep it? That style of (B heavy!) BKB alternator was fitted to Norman engined genny sets. I have one of the 240vac sets. ttfn Roland

Looking at the picture of the spec plate, maybe SEA could mean Self Exciting Alternator. P'raps the commutator could be for a DC starting winding?

Regards

Philip T-E

In message , philipte writes

That'd make sense - the BKB 3.5 KVA alternator I have is self-exciting (without commutator). If there was a DC starting winding then I'd expect to find some fairly meaty terminals for battery connection. If on the other hand it was for excitation then I'd expect some less thick wiring disappearing into the region of the stator and field coils.

TTFN

Pete

I reckon the comm is just a dc exciter and the output control is just manual field regulation for the load and with it being stood for a long time there's still no residual magnetism even for the dc to start. I *still

Martin

Comm and slip ring combo looks very like the arrangement of the Transmotor alternator on my Danish military set. In that case the comm supplies exitation current to the stator via a rheostat to fine tune the output voltage. If you remember, that took a fair bit of getting going due to oxide film on comm and low residual magnetism. A good clean and applying some dc volts to the field coils did the trick.

Kim, I'd say from the resistance of the regulator (if that says 0.4 ohms) that a 12V battery across the field should do the trick if it's gone flat, like wot Martin says. When you polarise a dynamo, put a bleed resistor (in this case say a headlamp bulb) across the winding, to avoid damaging the insulation with a high voltage kick when you break the battery circuit. You might like to check a few things first though: Lift the DC brushes off the com and check for a field circuit of a few ohms between them. Make sure it's going at full speed, it probably won't do anything much below 3000 rpm. Also check for shorts on the AC side, as it may not self-excite into a short circuit, which is a good thing. Has it definitely worked with that engine? If not, it could be rotating the wrong way, which doesn't matter on some alts, but this is like a shunt dynamo with an extra AC winding and the polarity of the shunt field connections to the com depend on the direction. HTH Lucien

"Oily" wrote > I reckon the comm is just a dc exciter and the output control is just manual