Work

In general

Work

Work is energy transfer associated with a force acting through a distance

If the system does work (W+), if work is done to the system (W-)

From Thermo

Intensively
$w=\frac{W}{m}$
Modes of work transfer:

• Work of compression/expansion
• Electrical work
• Shaft work
• Spring work
• Magnetic work
• Electrical polarization work

Mechanical Work

Work is
$w_{1-2}={\int }_1^{2}Fdx$

Shaft Work

$W_{sh}=\frac{T}{r}\left(2\pi r\right)n$
Where T=Fr and n is the # of rotations.

Shaft Power

$W_{sh}^{\prime }=2\pi n^{\prime }T$
Where n’ = revolutions per time and the units of W’ are KW

Work of Compression / Expansion

$W_{1-2}={\int }_1^{2}PAdx={\int }_1^{2}PdV$
Amount of work depends on the process path

Electrical Work

$W_e={\int }_1^{2}VIdt$
For a constant V and I
$W_e=VI\Delta t$
and
$W_e^{\prime }=VI$
If motor and pulley are 100% efficient, sole effect would be raising a weight.

From Power Electronics

$w=P_{avg}\cdot t$

Work Efficiency

Work Efficiency