Siemens TV Converter Box 611 User Manual

 

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 

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. 

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, 6SN1197-0AD00-0BP7 

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