The starting with primary reactor is a starting method similar to that with primary resistor, being inserted to it an inductive reactance in the phases of feeding Gates A70 Hi-Power II Belts. In practice, this method is applied only at the start of large and medium voltage motors (above 600V). In relation to the starting method by insertion of resistor, the reactor insertion provides a comparatively much lower energy consumption in the inserted element, but causes in a worse factor of power at the start, since the absorbed current will be reactive, mainly at the beginning of the acceleration .

In the starting method with primary resistor the insertion of resistors in each phase of the motor power leads to a decrease in the voltage applied to the terminals and, consequently, to a reduction in the absorbed current and in the conjugate electric motor. The disadvantage of this starting method is the loss of energy that happens to the resistors themselves. As the system accelerates, the fall in the current absorbed by the motor causes the voltage applied to the motor terminals to increase gradually. It is customary that the inserted resistance is gradually reduced by withdrawing resistors over the acceleration time. This is a method that is rarely used in practice.