Motor Operates With A Periodic Duty Cycle - Siemens SINAMICS S120 1PM6 Configuration Manual

2.3.5

Motor operates with a periodic duty cycle

The duty cycle determines how the drive is dimensioned. It is assumed that the speeds
during the duty cycle lie below the rated speed.
If the power is known, but the torques during the duty cycle are unknown, then the power
must be converted to a torque:
M = P ∙ 9550 / n
The torque to be generated by the motor comprises the frictional torque M
torque of the driven machine M
M = M
The accelerating torque M
M
B
J
motor+load
Δn
t
B
Figure 2-2
The M
1PM6/1PM4 Hollow-Shaft Motors for Main Spindle Drives
Configuration Manual, PPMS, 04/2008, 6SN1197-0AD23-0BP0
M in [Nm], P in [kW], n in [rpm]
+ M + M
friction load B
is calculated as follows:
B
Acceleration torque in Nm referred to the motor shaft (on the motor side)
Total moment of inertia in kgm
Speed variation in rpm
Acceleration time, in s
Periodic duty cycle (example)
torque must be calculated from the load cycle:
rms
2.3 Selecting and dimensioning induction motors
and the accelerating torque M
load
(on the motor side)
2
Configuring
, the load
friction
:
B
29