Okay so the so I had some issues with the prototype (small cog slipping on the motor, stripping the belt and lowish top speed). Most of the problems stem from poor cog and belt selection, so its time to rethink these. As always I’ve been looking over other peoples sucessful projects.
What do these have in common.
- They all have wider belts than what I had. Somewhere between 9mm-15mm wide
- All have bigger teeth. Most are 5mm (mine was 2.03mm)
- All have larger small cogs than what I selected. (15t small to 30t large a 2×1 ratio for the large 3000w motors for the Endless Project. While mine was 18t to 70t with a 2.03mm teeth spacing on the belt)
Some quick maths that I should have done on the gear ratio.
- The NTM 5060 motor I selected has a 380kv (kv is a measure of rpm/v)
- The batteries supply 22.2v
- 380 x 22.2=8436 rpm
- Wheel diameter = 70mm or 0.07m
- Circumference = pi x .07 = 0.2199 metres
- Circumference x rpm = 2199 x 8436 =1855.17 meters per minute
- in kilometers per hour = 111.3km/h (this is the speed of the motor itself)
My current gear ratio was 18 teeth to 70 teeth (3.8 ratio) so the maximum speed was only ever going to be 29.3 kph if the motor was running at full steam under the best possible situation.
I should really be looking for about a 2.5 ratio making the max speed around 44.5kph