What makes e-bikes go? 

How Brushless Motors work and their Benefits

Brushless DC (BLDC) systems combine the positive attributes of AC and DC systems. As a result, their usage in new applications continues to grow.

Permanent magnet (PM) designs are the most common brush type DC motors sold on the market today. They employ permanent magnets on the stator which in turn react with wound electromagnets on the rotor. These DC motors incorporate carbon brushes which slide over and transmit electrical power to the commutator which in turn switches power to the rotor windings to provide smooth rotation. Benefits of this design include a linear speed-torque performance which is easily controlled, a small motor diameter, predictable torque throughout a wide speed range, high starting torque, and minimal wiring.

                                                       
Cut-away view of a conventional permanent-magnet DC motor assembly (left)
Cut-away view of a brushless DC motor assembly (right)
                                                

Some common BLDC advantages include:

• Ability to control motors over a wide range of speeds
• Precise speed regulation without additional cost
• Rapid acceleration and deceleration capability
• Starting torque and dynamic response equal to or better than conventional DC drives
• Ability to operate several brushless drives from a common DC bus
• No mechanical wear or conductive brush dust from brushes

Electronic commutation in brushless drives eliminates need for brushes in the motor, and therefore all associated maintenance. Brushless drives use hall-effect sensors located within the motor to determine the rotor position for proper commutation and determination of which power transistors to turn ON to obtain maximum motor torque. Since commutation now becomes electrical, only motor bearings suffer from mechanical wear. BLDC motors run at higher speeds than PM DC motors because the frictional components of mechanical commutation do not limit their speed and higher efficiencies can be achieved at higher speeds. BLDC motors provide more reliable performance since environmental issues such as humidity or elevation do not play a part in the now non-existent brushes, brush film, voltage drops, and mechanical wear. If properly sized, and properly packaged, your next BLDC motor could handle all your electric scooter needs and last you a lifetime.

Summary

Brushless Motors deliver...

- Higher speed
- Higher Torque per size and weight
- Higher acceleration due to lower inertia
- No RFI/EMI
- Lower temperature rise

Veloteq products all use brushless dc motors.

36 Volt or 48 Volt system?  Which is better?

Assuming that both units are using the same motor capable of attaining the same travel speed, it becomes a matter of endurance of the power supply.  In a relatively level area a 36V system is sufficient to provide both the same speed and nearly the same travel distance while weighing less than a 48V system.

In hilly areas, however, the batteries discharge more rapidly dissipating the stored electrical energy and producing heat.  The 48V system is more capable of reaching the top of climb without resorting to pedal assistance.  The higher endurance of the 48V system also tends to reduce the added battery weight factor.  The recharge time is relatively the same for both systems.  With lighter weight e-bike models the 36V system should perform as well as the 48V system.

Veloteq has both 36V and 48V systems available matched to the bike models to achieve maximum performance.