Enter the base speed and maximum speed into the calculator to determine the field weakening ratio.
Field Weakening Ratio Formula
The following formula is used to calculate the field weakening ratio for a given base speed and maximum speed.
FWR = M / B
Variables:
- FWR is the field weakening ratio
- B is the base speed
- M is the maximum speed
To calculate the field weakening ratio, divide the maximum speed by the base speed. A higher ratio indicates the motor can be operated farther beyond its base speed (typically in the field-weakening/constant-power region).
What is a Field Weakening Ratio?
The field weakening ratio is a measure used in electric motor control to describe the relationship between the base speed and the maximum speed of the motor. Field weakening is a technique used to extend the speed range of a motor beyond its base speed by reducing the magnetic field strength. This allows the motor to operate at higher speeds, but with reduced torque. The field weakening ratio is an important parameter in applications where variable speed control and high-speed operation are required, such as in electric vehicles and industrial machinery.
How to Calculate Field Weakening Ratio?
The following steps outline how to calculate the Field Weakening Ratio.
- First, determine the base speed (B) of the motor.
- Next, determine the maximum speed (M) of the motor.
- Next, calculate the field weakening ratio using the formula FWR = M / B.
- Finally, calculate the Field Weakening Ratio.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Base Speed (B) = 1500 RPM
Maximum Speed (M) = 3000 RPM
Field Weakening Ratio (FWR) = M / B = 3000 / 1500 = 2.0