Starting device and circuit for starting single phase motors

A method for starting a single phase motor having a start winding and a run winding through an auxiliary starting circuit comprising the steps of:

• surrounding a voltage sensing coil with a current sensing coil;
• electrically connecting an auxiliary start capacitor and a set of normally closed contacts in series with said current sensing coil, said current sensing coil being preset to open said normally closed contacts upon sensing amperage representing maximum RPM of the motor;
• electrically connecting said voltage sensing coil in parallel across said set of normally closed contacts to sense no voltage when said normally closed contacts are closed and to detect voltage upon said contacts being opened;
• electrically connecting said series connected auxiliary start capacitor, current sensing coil and normally closed contacts in parallel with the start and run windings of the motor;
• and
• applying electrical power to the common and run terminals of the motor;
• whereby
• said current sensing coil becomes energized upon detection of amperage representing full motor speed to open said normally closed contacts and disconnect the electrical connection between said auxiliary start capacitor and the start and run windings;
• and
• the instant said contacts are opened, said voltage sensing coil detects the voltage across the start and run terminals of the motor less the voltage drop across the auxiliary start capacitor and becomes energized to maintain said contacts in the open position as long as power is applied to the motor and becomes de-energized upon detection of no voltage to close said contacts and reconnect said auxiliary start capacitor to allow the re-application of electrical power to the start and run windings of the motor for starting the motor through the auxiliary starting circuit.

An auxiliary starting device adapted to be connected by only two interchangeable wires to a single phase motor having a start winding and a run winding, the device comprising;

• an integral electro-mechanical switching relay circuit adapted to be placed electrically in parallel with the existing start and run windings when the motor is started, said switching relay circuit sensing both amperage and voltage and including an auxiliary start capacitor and normally closed contacts, and being preset to open said normally closed contacts upon sensing amperage representing maximum RPM of the motor and upon said contacts being opened to sense voltage and maintain said contacts in the open position;
• a pair of non-polarized wire leads each having one end connected to said switching relay circuit and a free end, and said wire leads being interchangeably electrically connected in parallel with the start and run windings of the motor;
• said switching relay circuit becoming energized upon detection of amperage representing full motor speed to open said normally closed contacts and disconnect the electrical connection between said auxiliary start capacitor and the start and run windings of the motor, and the instant said contacts are opened, sensing the voltage across the start and run terminals of the motor less the voltage drop across the auxiliary start capacitor and becoming energized to maintain said contacts in the open position as long as power is applied to the motor and becoming de-energized upon detection of no voltage to close said contacts and reconnect said auxiliary start capacitor to allow the re-application of electrical power to the start and run windings of the motor for starting the motor through the auxiliary starting device.

An integral electro-mechanical switching relay circuit for use in an auxiliary capacitance starting circuit to sense both amperage and voltage for starting a single phase motor having a start winding and a run winding comprising;

• a voltage sensing coil surrounded by a current sensing coil;
• an auxiliary start capacitor and a set of normally closed contacts electrically connected in series with said current sensing coil, said current sensing coil being preset to open said normally closed contacts upon sensing amperage representing maximum RPM of the motor;
• said voltage sensing coil being electrically connected in parallel across said set of normally closed contacts to sense no voltage when said normally closed contacts are closed and to detect voltage upon said contacts being opened;
• said series connected auxiliary start capacitor, current sensing coil and normally closed contacts adapted to be electrically connected in parallel with the start and run windings of the motor;
• and
• said current sensing coil becoming energized upon detection of amperage representing full motor speed to open said normally closed contacts and disconnect the electrical connection between said auxiliary start capacitor and the start and run windings of the motor;
• and
• the instant said normally closed contacts are opened, said voltage sensing coil sensing the voltage across the start and run terminals of the motor less the voltage drop across the auxiliary start capacitor and becoming energized to maintain said contacts in the open position as long as power is applied to the motor and becoming de-energized upon detection of no voltage to close said contacts and reconnect said auxiliary start capacitor to allow the re-application of electrical power to the start and run terminals of the motor for starting the motor through the auxiliary capacitance starting circuit.