Abstract: A self-starting single-phase synchronous motor without an auxiliary coil comprises a diametrically magnetized permanent-magnet rotor and a two-pole stator provided with exciter coils. A PTC resistor (5) is arranged in the circuit (1) of the exciter coils. The PTC resistor is proportioned so that its resistance will increase to a continuously permissible load resistance value after approximately 0.5 to 1 sec.

Abstract: A motor protector of the type having a snap acting thermostatic element is shown particularly adapted for use with compressor motors in which a conventional three pin header is mounted on the compressor casing to allow electrical energization of the motor. An improved heat transfer path is formed between the windings of the motor and the thermostatic element of the protector by suspending the protector from one of the motor pins in optimum heat conductive relation therewith and thermally separated from the compressor casing and any component mounted on the other two pins.

Abstract: A microprocessor controlled motor starter is utilized in which the short term temperature differential between the rotor bars and the rotor end bells is accounted for by the microprocessor-based system as a function of operator programmed stall time and locked rotor current for the particular rotor in question. The latter information is supplied to the operator by the manufacturer of the motor. The foregoing takes into account a slight deviation between the shutdown temperature, which should be predicted as a function of the manufacturer's data, and the actual shutdown temperature as expressed by an exponential. In the event that the short term temperature differential is exceeded, the microprocessor will enter a TRIP routine causing the motor controller to shut the motor down, thus preventing serious damage to the motor.

Abstract: An overload protection arrangement for an electric motor, especially of a hand-held power tool, includes an electronic speed of rotation control arrangement which is, in turn, controlled by an overload circuitry which includes a positive temperature coefficient resistor situated in the winding of the electric motor and incorporated in a voltage divider. The output of the PTC-resistor is amplified by an amplifier and, when the temperature of the winding increases above an acceptable level, the maximum current which can be drawn by the electric motor is reduced to a level at which the winding cannot burn out even if the rotor of the electric motor is blocked. If the rotor can rotate freely, the speed of rotation thereof even at the reduced power input will be sufficient to assure rapid cooling of the device powered by the electric motor. A time-delay member consisting of a capacitor and a resistor is arranged in parallel with the operational amplifier.

Abstract: A combination starter-protector device for a winding circuit of a dynamoelectric motor comprises a housing structure having a perforated wall dividing the interior of the housing structure into starter and protector compartments. The starter compartment accommodates therein a positive temperature coefficient thermistor while the protector compartment accommodates therein a bimetal switch. The housing structure has two sets of terminals, one set of the terminals being adapted to be connected to the winding circuit of the motor whereas the other set of the terminals are adapted to be connected to a power source. The distance between the thermistor and the bimetal switch may be adjustable by the employment of a spacer element.

Abstract: A protective thermal relay comprises a main heater for heating a snap-action element of a bimetallic switch to open the switch. The main heater is connected in series with the motor or other device to be protected by the relay. There is also an auxiliary heater for the bimetal element that is energized through an abnormal condition detection relay, e.g., a negative phase sequence detector, when the abnormal condition occurs. The auxiliary heater is a positive temperature coefficient type and will heat and hold the switch in the motor off mode as long as the negative phase sequence or other abnormal situation remains.

Abstract: A protection device and circuit for a fluid pump or the like including a motor control relay MS for actuating relay contacts MS-1, MS-2, MS-3 that control the communication of power to a drive motor 10a, and a manual reset motor protection device 24 that deenergizes the control relay in response to sensed malfunctions. The motor protection device comprises a manual reset motor protector 40 having switch contacts 42 connected in series with the motor control relay and a tripping coil 44 which, when energized, opens the switch contacts. A current shunt path 46 including serially connected pump assembly mounted sensors 48, 50, normally shunts current around the tripping coil and is interrupted in the event of a sensed malfunction, causing the energization of the tripping coil which opens the switch contacts and deenergizes the drive motor. The switch contacts must be manually reclosed to reactivate the pump assembly.

Abstract: A circuit, safe against an overload, for incrementally varying the power to an electric blower motor used for heating, ventilating and conditioning vehicles, having a PTC resistor in series with other series resistors in the circuit.

Abstract: A thermoswitch is physically located on a portion of the current supply connector between the current source and the exciter winding of the starter motor. The portion, constructed as a simple strip with flaps holding the thermostat, influences the temperature-dependent control portion of the thermoswitch according to heating in the armature, field winding, and brushes of the starter motor. The thermoswitch turns OFF the starter system by interrupting current supply to the kick-in starter relay.

Abstract: A method of assembling a combination starter-protector device and mounting it in a preselected assembly position onto at least a pair of plug terminals associated with a housing having a dynamoelectric machine arranged therein and with the at least plug terminal pair connected in circuit relation with a winding circuit of the dynamoelectric machine. The combination starter-protector device includes a pair of separable casing members, a PTCR, an overload protector, and at least a pair of female terminals. In this method, the PTCR, the protector device and the at least female terminal pair are enclosed within the casing members, and a resilient means is releasably secured generally about a major peripheral portion of the casing members for retaining them against separation.

Abstract: Overload protection for a multispeed motor is provided in the form of a plurality of line break motor protectors positioned in good heat transfer relation with the motor windings and having heating elements in circuit with the motor windings to be responsive to excessive winding current and/or excessive winding temperature to disable the windings. Certain of the line break motor protectors are operational in more than one motor speed configuration. The line break motor protectors may be of the self-resetting temperature sensing variety and circuitry is included to insure that the motor does not restart until all protectors are reset subsequent to an overload condition.

Abstract: A reciprocating drive system moves a body of defined inertia, such as a carriage supporting electrostatic spraying means, at full speed between two points at which the direction of movement is reversed. The drive system includes an electric motor with polyphase stator windings and a squirrel cage rotor. Transducers responsive to the arrival of the moving body at the aforementioned points produce output signals controlling a phase switching system which reverses the direction of rotation of the motor. Reversal of the motor torque reverses the direction of movement of the moving body within a given travel and within a given time interval to full speed in the opposite direction. A stator current limiter provides positive coupling in an operative condition and no coupling in an inoperative condition with the motor running at full speed. The motor is selected so that the inertia of its rotor closely matches that of the moving body.

Abstract: This disclosure deals with a time delay cut-out circuit for the start winding of an AC electric motor. The circuit includes an electronic switch which is connected in series with the start winding and which may be selectively closed to energize the start winding. Time delay means is provided which, in response to current flow therethrough, provides a timing period. An auxiliary coil is inductively coupled to the motor windings and supplies current to operate the time delay means. The time delay means operates the electronic switch to energize the start winding during the timing period. The components of the circuit, except for the coil, are mounted in a capsule which may be plugged into the motor from the exterior of the stator. The time delay means includes a self heating, heat responsive device, and the components are sized and arranged to optimize the heat generation and dissipation properties and thereby obtain the desired operating characteristics.

Abstract: The invention is directed to a disconnect and overload bypass arrangement for a hand-held portable tool equipped with an electric motor supplied from a source of electrical energy and a manually operable on-off switch for switching the tool on and off. The arrangement includes a self-reclosing disconnect switch operatively connected to the motor to temporarily disconnect the same from the energy source in response to an overload condition; and, circuit control means for supplying energy to the motor at a reduced level when the disconnect switch is open whereby the motor will continue to operate at reduced torque pending self-reclosure of the disconnect switch and thereby provide the operator of the tool with an audible and visual indication that the motor has not been deactivated by manually actuating the on-off switch.

Abstract: The invention relates to a starter device for single phase, asynchronous motors, the starter device being of the type which provides a PTC resistor for series starting operation with the auxiliary winding. The starter device may be used for different types of motors by reason of an arrangement of contacts for connecting the main and auxiliary windings, starting capacitors and a two phase power supply which accommodates different modes of starting operation required by different motors.Three capacitor contacts provide for connecting capacitors in different ways relative to the PTC resistor and one of two sets of winding contacts may be selected to suit a desired mode of starting operation.

Abstract: A refrigerant compressor of the type driven by a single phase motor capable of operating at a low speed and a high speed. The motor, including four separate windings, a first set of high-speed two-pole auxiliary and main windings, and a second set of low-speed four-pole auxiliary and main windings all wound on the same stator core. Each set of windings is provided with independent line break protectors that enable each set of windings and protector to be optimized without affecting the other. A mandatory low-speed start system is incorporated that insures initial low-speed start even when conditions require high speed operation. Speed switching from one speed to the other is accomplished in the present system while the motor is running without causing interruption of compressor operation.

Abstract: A motor starting relay particularly adapted for use in starting single phase asynchronous motors comprises a resistor element of positive temperature coefficient of resistivity which is compactly arranged within a housing and engaged by electrical contact and terminals means of particular structure and of a material of relatively high thermal resistance in a novel way such that power dissipation or loss by the resistor is reduced to a very low level after it has performed its motor starting function but so that, at the same time, the resistor is adapted to cool more rapidly after interruption of motor operation to permit prompt motor restarting.

Abstract: An electrical control having a relay device, a solid state starter device and an overload protector device predeterminately arranged therein and connected in circuit relation.

Abstract: A housing is disclosed in which a positive temperature coefficient (PTC) of resistivity element is mounted a selected distance from but in thermal communication with a thermostatic switch also mounted within the housing.

Abstract: A prime mover adapted for energization to a preselected speed therefor across a power source. The prime mover has a pair of winding means for excitation so as to effect the energization of the prime mover generally to the preselected speed when it is energized across the power source. Means is provided in circuit relation with one of the winding means and the power source for inhibiting the excitation of the one winding means generally as the prime mover attains its preselected speed, and means is operable generally in response to the occurrence of a preselected condition with respect to the excitation of the other of the winding means for placing the inhibiting means in open circuit relation with the power source generally as the prime mover attains its preselected speed.A method of operating a prime mover, a method of interrupting the operation of means for inhibiting current flow therethrough, and a circuit are also disclosed.

Abstract: A combination starting and protecting device particularly useful with split phase motors such as those used with refrigeration compressors is disclosed in which an element of material having a positive temperature coefficient (PTC) of resistivity characteristic and a thermally responsive switch are disposed in the same housing. A thermal coupling of a preselected value between the PTC element and the thermally responsive switch is provided so that a desired reset or "off" time is obtained for the thermally responsive switch without affecting the "on" time.