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Small Brushless More Powerfull compare to Big Brushless motor ? Help me to understand


1 mW
Apr 3, 2012
Hello There,

I want to change motor to my E-Scooter.

My question: How can be, Small Brushless Motor, can be more powerfull compare to bigger Brushless motor ?

The winding is smaller
The magnets are smaller
Does the manufacturer give false information?
** Small motor cost 4 times more.

Here is the small Brushless Motor:
Stator Diameter: 68 mm
Stator Length: 45 mm
Motor Diameter: 80 mm
Motor Body Length:92 mm
Shaft Diameter: 8 mm
Weight: 1.6 kg
Motor Configuration: 12N14P
KV: 70 rpm/V
Voltage: 30-70 V
No-Load Current: 2A / 20V
Max Continuous Current: 85A / 60V
Max Continuous Power: 5000 W


Here is the Bigger Brushless Motor:
MY1020 460V DC 2000W Electric Brushless Motor 4500RPM
Model: MOTOR MY1020
Output :2000W
Rated Speed:4500r/min (max:5400RPM)
Diameter:107mm(AS SIZE PICTURE)


I would like to know what do you think about this.
5kW is highly optimistic for the rc outrunner. I have a similar one, it's not much use for more than about 2kW without getting roasting hot. The other one will probably actually take 2kW for considerable time. There's no fixed way of stating power. The little outrunner motors are generally massively over specified compared to their true capability.
Smaller RC style motors have generally have much higher *advertised* speed limits and power ratings, for 2 reasons:
  • smaller/lighter rotors produces lower mechanical stress from centrifugal forces, permitting higher speeds
  • their use cases generally don't require the same thermal/mechanical safety margins of the bigger motors made for continuous duty industrial use cases.
Large outrunner motors (e.g. this 1500W ebike hub motor) are power-rated at low speeds limited by their intended use cases. They can be driven much faster. Most large inrunner motors are limited to 4000~5000 rpm unless they have a special rotor construction (e.g. Tesla's carbon wrapped rotor).
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This youtuber made very good video about that issue:
I agree to friends.