VAXen at home
roger.holmes at microspot.co.uk
Fri Oct 19 05:22:43 CDT 2007
>> From a UK point of view 'motor' as in motor-generator would be
>> taken to
> some form of internal combustion engine.
> I have heard lots of references to 'motor-generators' but never an
Well it just depends who you are used to talking to. I am in the UK,
I own some WW2 kit with a brass plate saying 'Air Ministry Engine
Driven Alternator Set'. Another plate says Tangye-Ricardo and another
saying it was built by Tangye Ltd, Birmingham. Ricardo was a south
coast engine design consulting company. It has a two cylinder 3.5
litre diesel engine which runs at 1000rpm, a huge flywheel and a big
alternator with a smaller (about 15 inch long and 15 inch wide) DC
generator on the back to provide the excitation current for the
alternators field coils. The whole thing comes on rolled steel joists
as a frame and is about 10 foot long, 4 foot wide and 5 foot high. I
bought it to drive my ICT mainframe, so it is on topic.
> Devices used for AC to DC, DC to AC and voltage conversion using a
> electric motor coupled to a generator would be referred to as 'rotary
No, when I've talked to people (in the UK) about a rotary converter,
they were talking about a large 3 phase motor wired up with big
capacitors so that it could be started on a single phase supply and
once turning, the other two windings would provide the other two
phases whilst the pulses to the first winding would keep it running
at the right speed. Of course for a 10kVA supply, I would have needed
at least a 30kVA motor as only one phase was actually driving it.
>> It may be European vs US usage, but in the US "motor" almost always
>> means electric motor in this and other contexts. So what you
> That tends to be UK usage too. The thing under the bonnet (OK,
> hood) of
> a car is called an 'engine' over here. 'Motor' for that would be very
I agree, though motor is also used to mean motor car as in Ford Motor
Company, Dagenham or Vauxhall Motors, Luton.
> To me, a 'motor generator' is just that. An electric motor driving an
> electric generator, to be used to convert voltage/frequency, etc. A
> 'rotary converter' (or 'Dynamotor; if oyu go back far enough) is a
> simialr thing with common field windings/frame/etc rather than 2
> separate electrical machines with the shafts coupled.
>> call a "motor-generator" would be here just plain called a
> A 'generator' over here is either just the mechanical-to-electircal
> energy converter or , as you said, a heat engine coupled to such a
> machine. Certainly if you hired a 'generator' (as somebody
> suggested we
> should do for a VCF-type event), you'd expect to get something with
> engine included.
Yes, but generator also means a machine converting a turning motion
into DC. Cars prior to the mid sixties had generators, after that
they have alternators with a bridge rectifier.
> I don't know how common these other term are across the Pond, but an
> 'alternator' is an AC-output geneterator, a 'Dynamo' (short for
> 'Dynamo-electric machine' is a generator, normally DC output, with a
> wound field, and a 'Magneto' (short for 'Magneto-electric machine'
> is a
> genatore with a permanent magnet field. Which means the common bicycle
> dynamo (as it's normally called over here' is in fact a magneto....
I agree with all but the last part. A magneto is a coil mounted next
to a flywheel, the flywheel having a permanent magnet attached which
when it moves past the coil, generates an electrical spike which
drives the spark plug at exactly the right point in the engine cycle
for a two stroke engine, or for a four stroke, one spark is just
wasted, though it would be possible for the magneto to be run off the
camshaft. The Magento was in turn was a big advance on the old hot
tube ignition, but thats another story.
Apple 2,3,Lisa and Macs
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