Is this a dynamo?

Nick Highfield sent me the following letter.
I have put the pictures on my Webshots page for him.
See
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1 & 2
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Find attached a couple of snaps of the dynamo which I picked up at sodbury
for three quid. My first thought was that it had been bodged up out of bits
of telephone magneto, but it actually seems rather well made with the frame
and bearing plates held together by screws and locating dowels. Still looks
GPO to me though, does it ring any bells (ouch!) with you?
Nick H.
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I am ex GPO but it doesn,t look like a magneto to me.
--
Dave Croft
Warrington
England
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Reply to
Dave Croft
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Thanks for that Dave. Sorry if you received multiple emails but snipped-for-privacy@unusual.com bounced and I found I had several others for you so tried the lot!
Anyway, The device has a commutator so would probably *function* as a dynamo (or DC motor) even if that was not the original intention. However it would hardly be the last word in efficiency with a simple two pole unlaminated armature. It is this feature which put me in mind of an early telephone magneto, though these were of course AC permanent magnet devices (and probably rather before Dave's time!). BTW the small drive pinion is connected to the armature via a ratchet device.
Got to be a good three quid's worth though!
Ideas anyone?
Reply to
Nick Highfield
Might it be an early form of stepper motor?
I bought a ringing device too. Cost £7.00 and comprises a 110V motor, on a base plate with all sorts of wheels and gears. Missed a much nicer one for £35 though, three times the size!
Regards,
Kim Siddorn
Reply to
J K Siddorn
Certainly holds the armature firmly in position when the field is energised. But two steps only 180 degrees apart?
Reply to
Nick Highfield
Gentlemen,
My Grandfather was a renowned model engineer, he even made it onto the telly with his models Magpie to be exact, and he had a lifeboat powered by an electric motor of very similar design and shape.
Martin P
Reply to
Campingstoveman
"Campingstoveman" wrote > Gentlemen,
What sort of date would that have been?
One thing which makes me think that it was not intended as a motor is that with only two poles it would not be self starting.
BTW. Overall length is about 8" (should have included a ruler in the pics) and it is pretty heavy.
Reply to
Nick Highfield
Nick,
My Grandfather built model boats from long before I existed to the day he died which was eighteen years ago, the motor was was constucted of alluminium and had a reduction gearbox fitted and ran resonably fast. By the way on Sunday up to ten of us will be putting on a small show on at the Apple day event at Bromham Mill should you fancy another ride out and even plenty for the wives to see and do.
Martin P
Reply to
Campingstoveman
IIRC there should be a pointer attached to the end of the rotor.
I can't really remember how those imbalance indicators used to work, But it may be one of those. The rotor is the same as a GPO generator 4C and also 8AN.
May be wrong, The BT museum engineers may know. I don't have their number anymore, but they maintain the Linked earth exhibition at Amberly Chalk Pit.
Simon Taylor
Reply to
Simon Taylor
Could it have been an explosives detonator exploder?
JW² Norton AntiVirus 2003 installed ************************************
Reply to
Jack Watson
Ratchet ? That's a blasting dynamo. The old "Acme roadrunner trap" design with the plunger T handle.
-- Die Gotterspammerung - Junkmail of the Gods
Reply to
Andy Dingley
Andy Dingley wrote :-
Gentlemen, I think we have it! - That would explain the roller parallel to the drive pinion. it would have backed up the rack on the plunger.
What does one do with the bones of a detonator?
NHH
Reply to
Nick Highfield
In a book today I came across a reference to "Rackbar exploder" for use with low tension electric detonation fuses c1899. Could that be it? sadly no pic but a Google may turn one up. regards Roland
Reply to
Roland and Celia Craven
Cut a rack for it, obviously !
It's nearly the Festival Of Burning Catholics too, a celebration held to celebrate the quantities of cheap pyrotechnics available the next day.
-- Die Gotterspammerung - Junkmail of the Gods
Reply to
Andy Dingley
Restore it and the next time you miss with the hammer, don't just say "blast", do it!
Simon Taylor
Reply to
Simon Taylor
The pyrotechnics have already started here in W. London. Diwali is bigger than Guido Faukes night. don't know if any particular denomination is favoured for burning though.
NHH
Andy Dingley wrote (snip):-
Reply to
Nick Highfield

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