Quote:
Originally Posted by drkdgglr
Wouldn't you only benefit from this extra torque in a low kv & high voltage setup vs a high kv and low voltage setup?
Although the 1400kv motor would have more torque than a 1700kv, you'd have to gear the 1400kv motor higher to reach the same speed as the 1700kv motor.
I entered two buggy setups in the speedalc. Only difference between the two is gearing and motor. I used a 1515 3d (1360kv) and 1515 2.d (1650kv). According to the calc the 1360 kv has more motor torque, but the final torque is exactly the same as the 1650kv setup. I am assumng that both setups would have the same amp draw (this is were I could be going wrong)
1515 3d:
Total Motor Speed: 28886.4 RPM
Vehicle Speed: 34.83 mph (55.94 km/h)
Effective KV Value: 1301.19
KT constant: 0.99 oz-in/A
Motor Torque: 0.41 ft-lbs
Final Torque: 4.6 ft-lbs
Final Power: 1776 watts (2.4 HP)
1515 2.5d
Total Motor Speed: 35310 RPM
Vehicle Speed: 34.93 mph (56.12 km/h)
Effective KV Value: 1590.54
KT constant: 0.82 oz-in/A
Motor Torque: 0.34 ft-lbs
Final Torque: 4.62 ft-lbs
Final Power: 1776 watts (2.4 HP)
Another thing I was thinking is that you'll be running the 1360kv motor closer to it's max rated amps and will run hot easier?
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From what I've seen in my set ups, all the higher Kv motors geared for the same speed have always asked for more AMPs then with a lower Kv ones. It might have to do with the winding resistance (Rt) and the fact that most higher Kv motor have higher Io (No Load Current). For example: A Aveox 1415/2Y has a Rt of 0.022 Ohms and a Io of 1.8, now a 1415/1.5Y has a Rt of 0.010 Ohms and a Io of 2.5. I have tried the 2 motors above with 6S both geared for the same speed and the 1.5Y was always warmer and pulled more AMPs then the 2Y.