The series motor is a type of electric direct current motor in which the armature and the inductor debited or excitation are connected in series. That is why the excitation current or the inductor is also the current of the induced absorbed by the motor.
This type of direct current motor is also called the series excitation motor. The constitution of the electric motor in series is that of having all the elements of the circuit in series, induced windings and inductors. The series engine is characterized by having a high moment of rotation at start-up and its speeds very variable depending on the load, making it an unstable motor.
This is the type of engine used in applications where a large torque is required.
Characteristics of the series motor
The main features of the series electric motor are:
When operating under vacuum, there is a danger of packing because the speed of a direct current motor increases or decreases the flow of the inductor and, in a series motor, decreases with increasing speed, since the intensity in the inductor is the same as the non-induced.
The power is almost constant for any speed.
The abrupt variations of the supply voltage affect it very little, because an increase of this causes an increase of the intensity and, therefore, of the flow and the electromotive force, stabilizing the intensity absorbed.
Applications of the series motor
The series engine, due to its characteristics, is used in cases where a large torque is required: trams, locomotives ... and its use in electric traction is very practical.
A drill could not have a serial motor, because when the hole in the piece was finished, the machine would remain empty (without load) and the speed in the bit would increase so much that the machine would become dangerous for the user.