Direct match

Direct start is the starting system in which the electric motor receives full voltage at the moment of departure. The factors that prevent the starting of the motors directly from the secondary network are the power of the motor being greater than the maximum allowed by the local concessionaire and that the load to be moved needs slow and progressive drive. This is the simplest starting method because no special motor drive devices are used. Only contactors, circuit breakers or switches are used which allow the motor to be supplied with full voltage at the moment of starting.

The cage rotor motor can start at full load and with current increasing from four to eight times the nominal current, according to type and number of poles. The conjugate in the starting achieves almost 1.5 times the nominal torque. The motors can only be started directly from the mains if the following conditions are satisfied: the rated capacity of the network satisfactorily high so as to make the motor starting current irrelevant; the starting current of the motor of small value because its power is low; the starting of the motor is made without load, which reduces the duration of the starting current.