You are talking about a starting capacitor, this thing is not expensive, but for installation you may be charged about 100 for installation, which is not expensive when you spend 100.
Starting capacitors are AC electrolytic capacitors or polypropylene and polyester capacitors used to start single-phase asynchronous motors.
Single-phase motor flowing single-phase current can not produce a rotating magnetic field, need to take the capacitor used to split the phase, the purpose is to make the current in the two windings to produce nearly 90 ゜ ゜ phase difference, in order to produce a rotating magnetic field.
To make a single-phase motor can automatically rotate up, can be added to the stator in a starter winding, the starter winding and the main winding in the space difference of 90 degrees, the starter winding to be connected to a suitable capacitor, so that the current with the main winding in the phase of the approximate difference of 90 degrees, the so-called split-phase principle.
Such two in time difference of 90 degrees of current into the two in the space difference of 90 degrees of the winding, will produce (two-phase) rotating magnetic field in space. Under the action of this rotating magnetic field, the rotor can automatically start, after starting, when the speed rises to a certain point, with the help of a centrifugal switch installed on the rotor or other automatic control devices will start the winding disconnected, normal operation only the main winding work.
Principle of operation:
Capacitor induction motors have two windings, namely, the starting winding and the running winding. The two windings are 90 degrees apart in space. In the start winding on the series of a larger capacity capacitor, when the run winding and start winding through the single-phase alternating current, due to the capacitor effect so that the start winding current in time than the run winding current ahead of the 90-degree angle, the first to reach the maximum value.
The formation of two identical pulsed magnetic fields in time and space, so that the air gap between the stator and rotor generated a rotating magnetic field, under the action of the rotating magnetic field, the motor rotor generates induced current, the current interacts with the rotating magnetic field to generate electromagnetic field torque, so that the motor rotates.