does the dynamo body need to be earthed ?, it is a two wire system and can be polarised either way by simple flashing, I'm thinking it would prevent polarisation if it were necessary to be earthed
A bit off-topic but; My limited understanding is that YES- it needs to be earthed, which the body *normally* does. The green wire feeds the field coil, and the yellow wire uploads the hefty (up to)~10amps
to the regulator...I've run a earth wire to battery from the common field/brush wires terminate on the bearing boss in the body, I do this because my (dynamo) body is a bit crusty so don't fully trust it ...
To answer the question
Does the dynamo get hot ?
......dunno, I guess so- depending on the ambient air temp, the demand on the unit, and the transferred heat from however hard you ride the motor. Maybe buy a small oven thermometer and stick it in there and let us know, everywhere will be different.
You posted while I was writing;
I was considering covering the top/visible part with either aluminium tape or a shaped piece of stainless steel.
I'd say the more free air they have the better