A quick little project that was prompted by a couple of threads on ME Forum where a member was having problems with a Stuart Dynamo where the field blocks were not cast centrally and the magnet a bit weak.
I decided to see if I could make something similar. So it's about the same size as the Stuart offering, looks a bit more like the PMR one at least from the brush end and also has the look of an old Motor/Dynamo with the radial slots at the other. It uses the rotor, magnets, bearings and brushes from an ebay sourced 775 DC Motor with a new body and end caps plus a few insulators and thumb nuts. Depending on what you have in the way of metal stock it would cost between £40 -50GBP including the motor which compares well to over £300 for the Stuart kit.
My old Stuart 10V was used as most people can relate to that. Air at around 30psi. I used a bit of scrap with a couple of O rings stretched over it as the pulley and ran that against the 10V’s flywheel and a couple of calculations show the dynamo is running around the 3000rpm mark for the light, probably a bit less on the other items and you can certainly hear the engine working under load when it is driving the smaller DC motor. It would be better set up with a belt at say 1:5 reduction then the 10V could be run a bit slower, currently it is about 1:3
I decided to see if I could make something similar. So it's about the same size as the Stuart offering, looks a bit more like the PMR one at least from the brush end and also has the look of an old Motor/Dynamo with the radial slots at the other. It uses the rotor, magnets, bearings and brushes from an ebay sourced 775 DC Motor with a new body and end caps plus a few insulators and thumb nuts. Depending on what you have in the way of metal stock it would cost between £40 -50GBP including the motor which compares well to over £300 for the Stuart kit.
My old Stuart 10V was used as most people can relate to that. Air at around 30psi. I used a bit of scrap with a couple of O rings stretched over it as the pulley and ran that against the 10V’s flywheel and a couple of calculations show the dynamo is running around the 3000rpm mark for the light, probably a bit less on the other items and you can certainly hear the engine working under load when it is driving the smaller DC motor. It would be better set up with a belt at say 1:5 reduction then the 10V could be run a bit slower, currently it is about 1:3
