safe
1 GW
- Joined
- Dec 22, 2006
- Messages
- 5,681
After a lot of number crunching and modifications of formulas (most recently the PWM Current Warping effect) I think I'm at the point of being able to present definitive evidence that gearing does have advantages that non-geared machines do not have and for the same amount of power output (the legal limit) one can go more, climb higher and run faster than a similiarly equipped non-geared machine.
The debate begins!
Let me start with the two test cases that I am going to be presenting results from:
Baseline Weight
Rider 185 lbs
Bike 100 lbs
5304 Hub Motor
72 Volts
35 Amp Controller (50% PWM effect... equals the Simulation chart)
Peak Power Output - 1970 Watts.
And the Geared bike:
1200 Watt Unite Motor
48 Volts
75 Amp Controller (50% PWM effect)
Peak Power Output - 1771 Watts.
8 Speed Internal Hub
Here's how I went about creating the charts. First I created a lookup table that would take the power output at a given rpm and would look up the corresponding precalculated (for a given bike of a certain size and weight) speed that could be attained at that given slope. I then created a table that would compare the value found in the first lookup to the value that the gearing would provide. At this point you know whether the motor can handle the relationship or not. If "not" then data point is rejected (can't climb or can't go that fast) if "yes" then it gets added to the possible values the bike can attain. For the Hub Motor the results are a simple straight line, but for a Geared bike the results get spread around a lot more.
Here are the results... First the Hub Motor and then the Geared bike:
The debate begins!
Let me start with the two test cases that I am going to be presenting results from:
Baseline Weight
Rider 185 lbs
Bike 100 lbs
5304 Hub Motor
72 Volts
35 Amp Controller (50% PWM effect... equals the Simulation chart)
Peak Power Output - 1970 Watts.
And the Geared bike:
1200 Watt Unite Motor
48 Volts
75 Amp Controller (50% PWM effect)
Peak Power Output - 1771 Watts.
8 Speed Internal Hub
Here's how I went about creating the charts. First I created a lookup table that would take the power output at a given rpm and would look up the corresponding precalculated (for a given bike of a certain size and weight) speed that could be attained at that given slope. I then created a table that would compare the value found in the first lookup to the value that the gearing would provide. At this point you know whether the motor can handle the relationship or not. If "not" then data point is rejected (can't climb or can't go that fast) if "yes" then it gets added to the possible values the bike can attain. For the Hub Motor the results are a simple straight line, but for a Geared bike the results get spread around a lot more.
Here are the results... First the Hub Motor and then the Geared bike: