The traits of an exceptional electric motor
1. Energy efficiency
2. Performance: Power to weight/dimension ratio
3. Reliability
4. Aesthetics
Weighing at 3.78kgs, our brushless PMDC motor with inbuilt planetary reduction gears and freewheel is built in-house with exceptional technical specifications. With minimal drag, a freewheel spins freely like a normal hub when the motor is not on. Contrarily, a Direct Drive motor with similar output is heavier and has a high drag when not powered. Riding electric bikes with direct drive would be very hard without the electric power.
1. Motor efficiency loss can be attributed to:
a) Resistance in the copper wires used in the motor.
Using high grade copper, we achieve minimal winding resistance in our motors.
b) Iron loss as a result of Eddy currents.
We reduced this to the min. by using high grade silicone steel plates (for thinness)for the stator.
c) Parasitic lost from bearings and other mechanical moving parts.
We employ high quality bearings from Japan NMB and Germany FAG. Dow Corning silicone greases for the planetary gears.
eZee Gen 3 motor has an efficiency of 83 % with 250 rpm and 25 Nm of Torque. It is essential to qualify the torque output together with the speed.
2. Power / weight and dimension ratio.
As a permanent magnet motor the obvious critical component is the magnet.
We use N35UH Neodymium magnets that retains magnetic properties up to 180°C, fitted in optimum size with min. air gap to the stator.
US / Canada nominal rated 500 watts motor delivers 30 Nm torque with 200 rpm speed at 22 amps or 800 watts.
It weighs 3.78 kgs and has a diameter 186 mm. An ideal dimension and weight ratio for its power output. Our nominally rated 250 watts motors for EU market (EN15194), delivers that same high torque with a speed limit of 25 km/h or 200 rpm with 26” wheels.
3. Reliability
Using PWM ( Pulse Width Modulation ) technology, eZee’s motor uses state-of-the-art Honeywell SS41 Hall sensors. The planetary star gears are machined from cast Nylon 6 rods for high strength and durability. The motor hub covers are die cast and CNC machined from high grade Al alloy ADC 5, providing good corrosion resistance. Anodized black option gives provides even further corrosion resistance.
4. Aesthetics
Hub motor covers are available in gloss finish and machined surface, or also available in anodized black or silver hubs.Simple, elegant, easy to clean and maintain.