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Overview

There are two types of brushless DC (BLDC) motors:

KV Value​

The KV value of a motor indicates its RPM per volt. A higher KV value means the motor will spin faster at a given voltage, while a lower KV value indicates more torque but less speed.

Internal Resistance​

The internal resistance of a motor affects its efficiency and heat generation. A lower resistance allows for higher current flow and better performance, while a higher resistance can lead to increased heat and reduced efficiency.

How to measure internal resistance​

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You measure the resistance between each of the three pairs of motor leads and then take the average of those three values to get your final line-to-line resistance. Here's the process summarized:

  1. Measure the resistance between U and V.
  2. Measure the resistance between V and W.
  3. Measure the resistance between U and W.
  4. Average the three readings.

How to measure internal resistance

How to choose a motor​

If your machine requires high torque (0.5 Nm or more), consider using a high-performance motor paired with a gearbox, such as a planetary gearbox. Otherwise, we recommend using a gimbal motor because choosing a high-performance motor without clear torque requirements can introduce unnecessary complexity and expense.