In message , Harry Bloomfield
writes

If rising heat from the bulb was enough to make it spin, rather than
the pump, why not use the heat produced by a resistor? It would be
completely silent.

Harry, the problem is that these devices have rarely if ever worked
properly since new. There just isn't enough heat to turn the beacon. It
is sometimes possible to get the beacon moving for a while with a quick
nudge, but it rarely spins for long. Another manufacturer (Lionel) had
a similar product which they withdrew and replaced with a motor powered
beacon because the heat version was unreliable.

What is the supply voltage of this gadget?

14v, although I use 12v, with the help of the little pump, which also
requires 12v. I have standardised on 12v for all bulbs and accessories.

Getting back to the pump, I was put off reducing the supply voltage
partly because it is convenient to have everything running at 12v, and
partly because, as was said, the pump may not start or run well on a
reduced voltage. I bought a Y piece to go in the tube, with one branch
running to the beacon and the other to a little plastic reducer valve
which allows fine tuning of the supply to the beacon, and works well.


--
Graeme