How does the addition of resistance in a Primary Resistor Starter affect voltage and current to the motor?

Adding resistance in a Primary Resistor Starter serves to limit the amount of voltage and current that reaches the motor during the starting phase. This is crucial because electric motors draw a significantly high inrush current when starting, which can be several times greater than their full-load current.

By incorporating resistance, the overall circuit impedance is increased, effectively reducing the voltage applied to the motor. This reduction in voltage, in turn, leads to a decrease in current according to Ohm’s Law, which states that current is directly proportional to voltage when resistance is constant. This helps in preventing damage to the motor and the power supply system during startup.

Using resistance allows for a controlled start, where the motor can gradually reach its operating speed. Once the motor is up to speed, the resistors can often be bypassed to provide full voltage and current for efficient operation. Thus, the answer correctly states that the addition of resistance in this context decreases both voltage and current to the motor during the startup phase.