Siemens Outboard Motor S120 Manual De Usuario
Configuring the motor
5.1 Procedure
5.1.1
General mechanical conditions
Moment of inertia
The kinetic energy generated by a rotating body is directly proportional to its moment of
inertia J in kgm
2
. The moment of inertia takes into account the rotating mass and its spatial
distribution across the entire volume of the body with respect to the rotary axes. The rotating
mass comprises the mass of the rotating mechanical structure (e.g. tool and holder) and the
mass of the rotor.
Frictional torque
The frictional torque M
r
is in opposition to the direction in which the rotor rotates. It can be
approximately calculated from a combination of the constant "adhesion component" M
RH
and
"sliding friction component" M
RG
. Both components also depend on the bearing used and its
load.
Depending on the mechanical design, loads here generally include axial forces and clamping
Depending on the mechanical design, loads here generally include axial forces and clamping
forces between the bearing components.
Further procedure
The moment of inertia of a suitable motor type can be used here initially.
If it transpires that the discrepancy between the assumed and actual moment of inertia is too
If it transpires that the discrepancy between the assumed and actual moment of inertia is too
great when further calculations are made, you then have to carry out a further iterative step
when selecting the motor. To calculate the frictional torque, use the relevant specifications
issued by the bearing manufacturer.
5.1.2
Specification of the duty cycle
Significance of the duty cycle
In addition to the frictional torque, you must also take into account the duty cycle when
selecting the motor. The duty cycle contains information regarding the sequence of motion of
the drive axes and the machining forces that occur in the process.
Motional sequence
The motional sequence can be specified as a rotation angle-time diagram, angular velocity-
time diagram, speed-time diagram, or angular acceleration-time diagram. The torques
resulting from the motional sequence (accelerating torque M
a
) are proportional with respect
to the angular acceleration α and moment of inertia J, and are in opposition to the
acceleration.
1FW6 Built-in torque motors
Configuration Manual, 05/2009, 6SN1197-0AE00-0BP3
Configuration Manual, 05/2009, 6SN1197-0AE00-0BP3
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