A

effective cross-sectional area of a coil, m ²

A

availability, A = MTBF/(MTBF + MTTR)

A( t)

availability function of a population of components as a function of time

a

scaling factor of time in a mother wavelet transform

?

scale parameter in a power law expression

? _n and b _n

strain coefficients for the strain energy of the stator core

? _t

cross-sectional area of a tooth, m ²

?

scale parameter in a Weibull function

? _r

resistance temperature coefficient, degree/ohm

? _s

skew angle of a stator, degree

B( f ₁ ,f ₂)

bispectrum

B

radial flux density in an airgap, Tesla

b ₁ or b ₂

stator or rotor side instantaneous radial flux density, Tesla

b

time-shifting parameter in a mother wavelet transform

?

shape parameter in a Weibull function

?

half-angle subtended by a shorted turn, degrees

C

volumetric concentration of a degradation product in a machine

C

Carter factor to account for airgap slotting

C ( y, v)

inverse wavelet transform

C( t)

cepstrum function

c

damping constant of a support system, N/m/s

D

damping factor for rotor vibrations

d

rolling element diameter, m

E

Young's modulus of a material

E _e

stored energy in an electrical system, Joules

e

specific unbalance e = mr/ M, m

e( t)

instantaneous induced EMF, V

?

strain in a material

?

MTBF of a component, ? =