What is the capacitor?

 The Capacitor.
        A capacitor is formed when two conductors, usually of aluminium, are separated by an insulator sus as paper ect. For use in motors the strips are rolled together into a compact unit and placed into a sealed metal or plastic container. This may be either cylinderical or rectangular in shape and may be mounted on, in, or away from the motor. Two terminals or leads are provied for connection. The name capacitor is descriptive of the operation of the device. The capacitor acts essentially as a storage units that is,has capacity to store electricity and provides a leading current to the auxiliary or starting winding. All capacitors have this quality and all are electrically the same;they differ only in mechanical construction.
    THE OIL-FILLED CAPACITOR
                This capacitor is used mainly in the permanent-split capacitor motor and for the two-value capacitor motor. The capacitor use an oil-impregnated paper as the dielectric and are permanently connected in the circuit. They are capable of constant duty and are substantially larger than an equivalent microfarad value in a electrolytic type. Different manufactures use many types of oil or synthetic liquids as the impregnating medium. Capacities ranges from 2microfarads to 50 microfarads of their type.
     THE ELECTROLYTIC CAPACITOR.
             Electrolytic capacitors are used mainly in capacitor- start and two- value capacitor motor. This type consists of two sheets of aluminum foil neat are separated by one or more layers of gauge. The gauge has previously been saturated with a chemical solution called an electrolyte. The electrolyte forms a film which acts as the insulating medium of the electrolytic capacitor. These layers are rolled together and fitted into an aluminum or plastic container. In an electrolytic capacitor motor-starting electrolytic capacitor should not be kept in a circuit more than a few seconds at a time because they are designed for only intermittent duty.
    CAPACITY
         Capacitors are rated in microfarads. A capacitor for motor starting may have a capacity ranging from 2 to 800 microfarad or more,depending on its use,size and type. Capacitors may lose some capacity because of excessive use, overheating, or other conditions, in such a case it may be replaced with one of approximately the original value of capacity and voltage; otherwise the motor may not have the required starting torque.
      When replacing a defective capacitor on a capacitor motor, be certain to use a replacement with a voltage rating at least as high as the original. Wherever any , question exists, it is always safter to use a capacitor of higher voltage rating.
       There are three types of the capacitor motor and each employes capacitor in conjunction with the windings. These are capacitor- start motor, the permanent split capacitor more have a relatively high starting torque and use the electrolytic capacitor. The capacitor must not be used for continuous duty and must be switched out of the circuit when the motor attains a predetermined speed. The permanent split capacitor motor has relatively low starting torque and use an oil impregnated paper as the dielectric. These capacitor remain in the circuit at all time. The two-value capacitor motor has a high starting torque and uses the electrolytic and oil capacitor in parallel at start. When the motor reaches the required speed, the electrolytic capacitor is cut out of the circuit permitting the motor to operate as a permanent- split motor.