Final answer:
The resistance in a split-phase motor is crucial for determining the thermal power dissipated, which depends on the squared current running through the motor. Back emf opposes the driving emf and increases with the motor's speed. Understanding these concepts is key to analyzing motor performance.
Step-by-step explanation:
The significance of the resistance in a split-phase motor is that it is responsible for the thermal power dissipated, which is proportional to the square of the current (P = I²R). A split-phase motor includes components such as the frame, windings of copper wire, and other electrical connections, which contribute to its overall resistance.
Examples of Calculations Involving Motor Resistance
For instance, consider a series-wound dc motor with a total resistance (Rf + Ra) of 2.0 ohms. When connected to a 120-V source, and drawing 10 A while operating at a constant angular velocity, we can determine various performance metrics such as induced back emf, mechanical power output, and power dissipation in the coil's resistance. Back emf in a motor opposes the input emf and increases with the motor's angular velocity.
Furthermore, in applications like a scotch yoke mechanism, where the motor rotates at a certain frequency, calculations may involve estimating the speed of motion induced by the motor's rotation. All these concepts underline the importance of understanding the resistance's role in motor operation.