Great discussions again, so I came to some more ideas : Using the dynamo for venting the primary case cannot be a serious proposition, so instead I chose to drill from there into the gearbox dip stick adapter, not a long way to do. So I expect to get any air out the gearbox dip stick cap and no oil leaks from there. Also no risk for washing or rain water to get into there. Some caps are vented some not so, at least in my old stock. So I did some Dremel grooving the thread for easier air venting, no hole on top.
As to dynamos, I do not like the Alton gearbox solution for offsetting the rotor drive. You have to care for lubrication in there . Instead I found some permanent magnet dc and three phase ac motors at small size so they can be fitted in this place after some minor milling the engine case for concentric motors with 68 mm o.d. . I will have a big magneto for ignition so all generated current will go into lighting only.
The dynamos - ahh, dc/ac motors got new longer front plates for twin sealed ball bearings on 8mm shafts for reinforcing this place. Sealing will be an o-ring machined in the motor front plate, no silicone or some such.
I did some power tests today with an electric hand drill and got these readings, revs corrected to crankshaft speeds, 1.25 lower than the dynamo sprocket:
The round dc perm mag. motor 68 mm o.d. performance was :
bulb 6 V 35 W : 6V at 1260 rpm
" 12 V 45 W 13.5 V at 2040 rpm
" quartz 12 V 60 W 12.6 V at 2020 rpm
" quartz 12 V 100 W 10.6 V at 1950 rpm
I could not get higher revs and voltage with the 100 W quartz because the hand drill did not pull it . So I guess at 2300 rpm I will get min. 12 100 W , but don´t really need that.
The square three phase ac motor and its three phase rectifier had these numbers:
6 V 35 W bulb 6V at 1160 rpm
12 V 35 W bulb 14 V at 2070 rpm
12 V 45 W bulb 13 V at 2030 rpm
12 V 60 W quartz 12.4 V at 2030 rpm
12 V 100 W quartz 11,4 V at 1950 rpm
again, slowed down by the drill at 100 Watt load.
So both motors are quite close in performance and show a very smooth pull with 8 or 9 poles. I do not have numbers to compare with the Alton but I believe they will satisfy me completely, no more night driving for me anyway. I got the motors from Aliexpress at € 40.- to 60.- each.
Vic
As to dynamos, I do not like the Alton gearbox solution for offsetting the rotor drive. You have to care for lubrication in there . Instead I found some permanent magnet dc and three phase ac motors at small size so they can be fitted in this place after some minor milling the engine case for concentric motors with 68 mm o.d. . I will have a big magneto for ignition so all generated current will go into lighting only.
The dynamos - ahh, dc/ac motors got new longer front plates for twin sealed ball bearings on 8mm shafts for reinforcing this place. Sealing will be an o-ring machined in the motor front plate, no silicone or some such.
I did some power tests today with an electric hand drill and got these readings, revs corrected to crankshaft speeds, 1.25 lower than the dynamo sprocket:
The round dc perm mag. motor 68 mm o.d. performance was :
bulb 6 V 35 W : 6V at 1260 rpm
" 12 V 45 W 13.5 V at 2040 rpm
" quartz 12 V 60 W 12.6 V at 2020 rpm
" quartz 12 V 100 W 10.6 V at 1950 rpm
I could not get higher revs and voltage with the 100 W quartz because the hand drill did not pull it . So I guess at 2300 rpm I will get min. 12 100 W , but don´t really need that.
The square three phase ac motor and its three phase rectifier had these numbers:
6 V 35 W bulb 6V at 1160 rpm
12 V 35 W bulb 14 V at 2070 rpm
12 V 45 W bulb 13 V at 2030 rpm
12 V 60 W quartz 12.4 V at 2030 rpm
12 V 100 W quartz 11,4 V at 1950 rpm
again, slowed down by the drill at 100 Watt load.
So both motors are quite close in performance and show a very smooth pull with 8 or 9 poles. I do not have numbers to compare with the Alton but I believe they will satisfy me completely, no more night driving for me anyway. I got the motors from Aliexpress at € 40.- to 60.- each.
Vic