EM 19: REPULSIUN MOTOR
To measure the torque characterlstlc and Starting current for a
repu1s1on motor
a repu1s1on motor is an Ac motor with a commutator but commutator winding is not connected to the mains as it is in a universal motor the motor brushes are shirt-circuited and the rotor current is induced from the stator ler us for a moment a motor with two excitation windings which provide rightangled magnetic fields in the rotor
urrent is induced
Winding No 1 induces a voltage in the rotor and a current occurs
due to the fact that the brushes are short-circuited. This current
is located in the magnetic field from the second winding (winding
No 2) and the motor torque is obtained in this way.
Normally, the two windings are combined to form one winding.
Turning the brushes changes the size relation between winding
No 1 and winding No 2 and thus changes the motor characteristics
for example, the speed at a certain load.
The repulsion motor is used in simple drive systems withvariable
speeds, e.g. small agitators, and shaking machines It is expensive
to purchase and the brushes and commutator become worn quickly
Consequently, it is now often replaced by,for example auniversal
motor with thyristor control.