Английская Википедия:Goodness factor

Материал из Онлайн справочника
Перейти к навигацииПерейти к поиску

Шаблон:Short description The goodness factor is a metric developed by Eric Laithwaite to determine the 'goodness' of an electric motor.[1][2] Using it he was able to develop efficient magnetic levitation induction motors.[3]

<math>G = \frac {\omega} {\mathrm{resistance} \times \mathrm{reluctance}} = \frac {\omega \mu \sigma A_\mathrm{m} A_\mathrm{e}} {l_\mathrm{m} l_\mathrm{e}}</math>

where

Шаблон:Math is the goodness factor (factors above 1 are likely to be efficient)
Шаблон:Math, Шаблон:Math are the cross sections of the magnetic and electric circuit
Шаблон:Math, Шаблон:Math are the lengths of the magnetic and electric circuits
Шаблон:Math is the permeability of the core
Шаблон:Math is the angular frequency the motor is driven at
Шаблон:Math is the conductivity of the conductor

From this he showed that the most efficient motors are likely to be relatively large. However, the equation only directly relates to non-permanent magnet motors.

Laithwaite showed that for a simple induction motor this gave:

<math>G \propto \frac {\omega \mu_0 p^2} {\rho_\mathrm{r} g}</math>

where Шаблон:Math is the pole pitch arc length, Шаблон:Math is the surface resistivity of the rotor and Шаблон:Math is the air gap.

References

Шаблон:Reflist