Stuart dynamo rotation

[Michael GilliganParticipant @michaelgilligan61133]

Posted by br on 09/02/2021 13:35:51:

Posted by SillyOldDuffer on 09/02/2021 13:24:28:

Dave

Just had a good look and NO BRUSHES .

On the spindle that rotates at the terminal end is a groove in a brass ring for a spring shaped wire that connects to each terminal.

Hope that makes sense . Bit difficult to photo..

Bill

.

Please see my previous note, Bill

A piece of wire running in a groove is effectively a BRUSH

If anyone wants to debate the semantics of that … feel free

[ I will not be participating ]

MichaelG.

[Former MemberParticipant @formermember12892]

[This posting has been removed]

[duncan webster 1Participant @duncanwebster1]

I think they they are called brushes because in the early days that's exactly what they were, but made from copper? wire instead of bristles or squirrel hair or whatever

[JasonBModerator @jasonb]

Yes "brushes" can take several forms, on the older equipment you can also find flat bronze strip or braided bronze/copper being used, A bigger dynamo here being built with the braided "brushes"

Edited By JasonB on 09/02/2021 17:16:02

[Michael GilliganParticipant @michaelgilligan61133]

Posted by br on 09/02/2021 16:35:41:

Thanks Michael for putting me clear on that. Appreciated.

I had been thinking of a carbon stick with a with a wire attached.

Bill

.

You’re welcome, Bill

Sorry if I was a little abrupt

MichaelG.

[Howard LewisParticipant @howardlewis46836]

I have always differentiated a Dynamo as generating DC, and an Alternator as generating AC, (because the voltage delivered at each output terminal alternated between Positive and Negative ).

So given the description by Stuart, to describe the machine as a Dynamo was incorrect.

The S E L and Trix low voltage motors of my youth were DC permanent magnet machines, but using Phosphor Bronze or Beryllium Copper strips as brushes. If motored, they could function as DC generators.

A lot of model locomotives have been / are powered by automotive Dynamos being supplied with DC from Lead Acid batteries.

The American A C Gilbert Erector and British Meccano motors used wound fields, and "carbon" brushes

The A C Gilbert motor had separate terminals for armature and field. I reversed mine, on an AC input, with a S E L reversing switch. The Meccano E20R motor had the reversing switch built in. Both would run on AC or DC current, like any motor described as "Universal"

The totally enclosed E20 version had only two input terminals and could not be reversed on AC, but by reversing the DC input..

It is now a while since I saw it, but from memory, the Dynamo driven by the National Gas Engine at The WaterWorks Museum employs metallic brushes,.

So perhaps the name came from the fact that the components "brushed" against the commutator?

Howard

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