2025 NEIEP Elevator Cab Assembly and Door Operators (530) Complete Practice Exam

When considering the movement of resistor R2 to the left in the context of a door motor operating speed, the correct interpretation is that this adjustment typically results in an increase in the motor speed. This phenomenon can be attributed to the way resistors affect electrical circuits.

In many motor control setups, resistors are used to regulate voltage and current flow. Moving R2 to the left often decreases the resistance in the circuit, thereby allowing more current to flow to the door motor. Increased current through the motor generally leads to a higher torque output, which in turn increases the speed of the motor.

This principle is rooted in Ohm’s law and the relationships between voltage, current, and resistance, which govern how electrical components interact within the circuit. With a lower resistance, and assuming the supply voltage remains constant, the current increases proportionately, enhancing the operating speed of the door motor.

Therefore, moving resistor R2 to the left directly correlates with an increased operating speed of the door motor, making the correct response to the question an increase in overall motor speed.