14 - PVD3627-August 2011
The motor adapted to the duty cycle has to provide the rms torque
M
rms
at the rms
speed(*) without extra heating. This means that the permanent torque
M
n
available at
the average speed presents a sufficient margin regarding the rms torque
M
rms
.
Selection of the motor :
(*) rms speed is calculated thanks to the same formula as that used for the rms
torque. The mean speed can not used (in general mean speed is equal to zero).
Only use the rms speed
Furthermore, each Mi and spee
d associated Ωi of the duty cycle has to be located in
the operational area of the torque vs speed curve
Torque
M
k
M
rms
.
M
n
M
i
Ωi
Ωk
Ω
rms
Ωn
Speed
Base speed
∑
=
∆
Ω
=
Ω
n
i
i
i
rms
t
T
1
2
*
1
