Speed control system and method for electric motor

Claim 2

In an electric motor having at least one main winding, a multi-position speed selector switch for energization of the main winding of operation of the motor at high speed and one or more slower speeds, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means connected in series with one of said at least one main windings and being energizable by said speed selector switch when said one main winding is energized thereby to result in operation of said motor at a speed slower than when said one main winding is energized, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 3

In a multi-speed electric motor having two or more main windings serially connected together, a multi-position speed selector switch for energization of one or more of said series connected main windings for operation of said motor at a predetermined speed corresponding to the number of said series connected main windings which are energized, a plurality of speed selector switch taps for the selective energization of a desired number of said series connected windings corresponding to a speed selected for said motor, the last of said series connected windings which when energized together with the others of said series connected main windings results in a low speed mode of operation for the motor, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means connected in series to one of said main windings and being energizable by said speed selector switch together with said one main winding thereby to result in operation of said motor at a speed slower than when said one main winding is energized, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 4

In a multi-speed electric motor having two or more main windings serially connected together, a multi-position speed selector switch for energization of one or more of said series connected main windings for operation of said motor at a predetermined speed corresponding to the number of said series connected main windings which are energized, a plurality of speed selector switch taps for the selective energization of a desired number of said series connected windings corresponding to a speed selected for said motor, the last of said series connected windings which when energized together with the others of said series connected main windings results in a low speed mode of operation for the motor, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means connected in series to one of said main windings and being energizable by said speed selector switch together with said one main winding thereby to result in operation of said motor at a speed slower than when said one main winding is energized, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 5

In a motor as set forth in claim 2 further comprising means in parallel with said capacitor means for shunting said capacitor upon start-up of the motor thereby to increase the starting torque of the motor and for unshunting said capacitor means after start-up of the motor thereby to permit the motor to operate at said slower speed.

Claim 6

In a motor as set forth in claim 3 wherein said shunt means is a positive temperature coefficient variable resistor which has a low initial resistance and which, after energization, has a significantly higher resistance.

Claim 7

In a motor as set forth in claim 2 further comprising a bleed resistor in parallel with said capacitor means thereby to discharge said capacitor means upon de-energization of the motor.

Claim 8

In a multiple speed induction motor including a first main winding, a second main winding, said main windings being serially connected together, a multiple position speed selector switch having a movable switch element, a first tap between said first and second main windings, said movable switch element being selectively connected with said first tap for energization of said first main winding and for operation of said motor at a first speed, and a second tap on the side of said second main winding opposite said first main winding, said movable switch element being selectively connected with said second tap for the serial energization of said first and second main windings and for operation of said motor at a second speed slower than said first speed, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means series connected to said second main winding, a third tap on the side of said capacitor means opposite said second main winding, said movable switch element being selectively connected with said third tap for energization of both of said main windings and said capacitor means only when said movable switch element is connected to said third tap thereby to operate said motor at a speed slower than said second speed, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 9

In a multiple speed induction motor including a first main winding, a second main winding, said main windings being serially connected together, a multiple position speed selector switch having a movable switch element, a first tap between said first and second main windings, said movable switch element being selectively connected with said first tap for energization of said first main winding and for operation of said motor at a first speed, and a second tap on the side of said second main winding opposite said first main winding, said movable switch element being selectively connected with said second tap for the serial energization of said first and second main windings and for operation of said motor at a second speed slower than said first speed, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means series connected to said second main winding, a third tap on the side of said capacitor means opposite said second main winding, said movable switch element being selectively connected with said third tap for energization of both of said main windings and said capacitor means only when said movable switch element is connected to said third tap thereby to operate said motor at a speed slower than said second speed, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 10

In a motor as set forth in claim 6 further comprising means in parallel with said capacitor means for incipiently shunting said capacitor upon start-up of the motor thereby to increase the starting torque of the motor and for unshunting said capacitor means of the motor after start-up of the motor thereby to permit the motor to operate at said slower speed.

Claim 11

In a motor as set forth in claim 7 wherein said shunt means is a positive temperature coefficient variable resistor which has a low initial resistance and which, after energization, has a significantly higher resistance.

Claim 12

In a motor as set forth in claim 7 further comprising a bleed resistor in parallel with said capacitor means thereby to discharge said capacitor upon de-energization of the motor.

Claim 15

A method as set forth in claim 10 wherein said motor comprises a plurality of series connected main windings including a first set of windings and a last set of windings, said switch being operable to selectively energize one or more of said series connected windings therby to permit operation of said motor in a high speed mode when only a first of said first series connected winding is energized and to permit operation of said motor at its slow speed mode of operation when said last set of windings is energized together with the other sets of windings, said method further consisting of serially connecting said capacitor means to all of said serially connected windings thereby to permit operation of said motor at a speed slower than said slow speed mode of operation.

Claim 16

In an electric motor having a main winding, a multi-position speed selector switch for energization of the main winding thereby to permit operation of the motor at a preselected speed, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means connected in series to said main winding and being selectively energizable by said speed selector switch thereby to serially energize both said main winding and said capacitor means for operation of said motor at a speed slower than the operation speed of the motor when only said main winding is energized, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 17

In an electric motor having a main winding, a multi-position speed selector switch for energization of the main winding thereby to permit operation of the motor at a preselected speed, said motor being adapted to be connected to a source of line voltage, wherein the improvement comprises: capacitor means connected in series to said main winding and being selectively energizable by said speed selector switch thereby to serially energize both said main winding and said capacitor means for operation of said motor at a speed slower than the operation speed of the motor when only said main winding is energized, said one main winding being energized by said line voltage when said motor is operated at high speed and being energized by a voltage less than said line voltage upon energization of said at least one main winding and said capacitor means when the motor is operated at said slower speed.

Claim 20

In an overhead ceiling fan having a fan motor, the latter comprising a stator assembly including at least one main winding, a rotor assembly, said rotor assembly having a rotary axis adapted to extend generally vertically when the fan is in its operating position, said fan motor further having stationary means extending axially through the motor for housing a plurality of wires, said ceiling fan further having means on the lower, outboard side of said motor for securement of one or more fan blades thereto whereby said securement means together with said fan blades rotate with said rotor assembly, said stationary means extending through and out beyond said fan blade mounting means and having a switch housing mounted thereon, said switch housing having a multi-position speed selector switch therewithin and means for selective operation of said switch, said switch being electrically connected to the winding of said motor and to a source of line voltage via said plurality of wires extending axially within said stationary means, said motor being operable at a high speed mode of operation when said at least one main winding is energized by said line voltage, wherein the improvement comprises: capacitor means housed within said switch housing and electrically connected to said main winding and being selectively energizable in series with said main winding thereby to result in the application of a voltage to said at least one main winding less than said line voltage and to result in operation of said motor at a speed slower than when only said main winding is energized.

Claim 21

In an overhead ceiling fan having a fan motor, the latter comprising a stator assembly including at least one main winding, a rotor assembly, said rotor assembly having a rotary axis adapted to extend generally vertically when the fan is in its operating position, said fan motor further having stationary means extending axially through the motor for housing a plurality of wires, said ceiling fan further having means on the lower, outboard side of said motor for securement of one or more fan blades thereto whereby said securement means together with said fan blades rotate with said rotor assembly, said stationary means extending through and out beyond said fan blade mounting means and having a switch housing mounted thereon, said switch housing having a multi-position speed selector switch therewithin and means for selective operation of said switch, said switch being electrically connected to the winding of said motor and to a source of line voltage via said plurality of wires extending axially within said stationary means, said motor being operable at a high speed mode of operation when said at least one main winding is energized by said line voltage, wherein the improvement comprises: capacitor means housed within said switch housing and electrically connected to said main winding and being selectively energizable in series with said main winding thereby to result in the application of a voltage to said at least one main winding less than said line voltage and to result in operation of said motor at a speed slower than when only said main winding is energized.

Claim 22

In an overhead ceiling fan having a fan motor, the latter comprising a stator assembly including at least one main winding, and a rotor assembly, a multiple position switch located remote from the motor and a plurality of wires extending between said switch and said stator assembly, said switch being electrically connected to said at least one main winding of the motor and to a source of line voltage, said motor being operated at a high speed mode of operation when said at least one main winding is energized by said line voltage, wherein the improvement comprises: capacitor means located remotely from said motor, said capacitor means being selectively electrically energized in series with said at least one main winding via said switch thereby to result in the application of a voltage to said at least one main winding less than said line voltage and to result in operation of said motor at a speed slower than when only said at least one main winding is energized.

Claim 23

In an overhead ceiling fan having a fan motor, the latter comprising a stator assembly including at least one main winding, and a rotor assembly, a multiple position switch located remote from the motor and a plurality of wires extending between said switch and said stator assembly, said switch being electrically connected to said at least one main winding of the motor and to a source of line voltage, said motor being operated at a high speed mode of operation when said at least one main winding is energized by said line voltage, wherein the improvement comprises: capacitor means located remotely from said motor, said capacitor means being selectively electrically energized in series with said at least one main winding via said switch thereby to result in the application of a voltage to said at least one main winding less than said line voltage and to result in operation of said motor at a speed slower than when only said at least one main winding is energized.