Explanation of a MULTISIM circuit

[Amaravian]

I need explanation for multisim14 circuit which measures speed of PM DC motor. Could anyone please explain about the need for the DC source at the speed terminal of the motor. the circuit can be found out in the example ckts of multisim 14 in machine category

[nestor-sg]

Hi Amaravian:

That V2 dc source is used to simulate a constant speed load. You can see how it is linked to a rad/s to rpm converter. In other words, in the mechanical domain you are saying 20 rad/s...convert them to RPM...so they are used in the DC machine as a constant speed load.

You can highlight (select) the RAD_PER_SEC_TO_RPM component and press F1 to pull the Help for this part.

You can also, in the Multisim Help (Help > Multisim Help) find information about simulating in the mechanical domain if you go to Contents  tab > Component Reference > Electromechanical Components > Machines and find some topics, like Machine Modeling and Designing in the Mechanical Domain.

Hopefully this helps understand these concepts.

Regards,