Siemens SIMOTICS T-1FW6 - General Mechanical Conditions

Configuration
5.2 Configuring workflow
1FW6 Built-in torque motors
96 Configuration Manual, 07/2017, 6SN1197-0AE00-0BP9
5.2.1
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
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
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.