Abstract: An electric motor drive system with an overload protector for the electric motor (10) is proposed, wherein the electric motor drive receives a signal from an input unit (18) for predetermining a desired position of a movable component. When the overload protector responds, the desired position changes to a predeterminable resting position of the movable component, which is taken by the movable component before the electric motor (10) is switched off. Apart from preventing the thermal destruction of the electric motor (10), the electric motor drive system according to the invention prevents subsequent damage, which could occur due to the fact that the component moved by the electric motor (10) could take an undefined position when an overload of the electric motor (10) occurs.

Abstract: A circuit controller for selectively connecting a power source to a load includes a switching mechanism, which selectively connects the power source to the load and switches a current which flows through the switching mechanism, and a substantially radiant energy dissipating positive temperature coefficient current limiter for limiting the current which flows through the switching mechanism. The switching mechanism includes a current sensor, which senses the current flowing through the switching mechanism and provides a sensed current value, and a switching controller for disconnecting the power source from the load whenever the sensed current value is above a predetermined current value. The switching mechanism may include a contactor having separable contacts which are responsive to the switching controller. The current limiter may have a first resistance which results from a first series current, and a higher second resistance which results from a second series current.

Abstract: A temperature-sensitive switch (10) for protecting electrical parts against excess temperature and/or excess current comprises a bimetallic switching device (14) which opens or closes its contacts in response to an excess temperature. Said switching device (14) is contained in a casing (17) having a pot-like bottom part (18) and cover (19). A first heating resistor (15) is connected in circuit with the switching device (14) such that it locks the switching device (14) in a self-holding manner when said switching device (14) is actuated in response to an excess temperature. A second heating resistor (16) is connected in circuit with said switching device (14) and produces heat in response to a current flow therethrough. When an excess current flows through the second heating resistor (16) the switching device (14) is actuated. Both, the first and second heating resistors (15, 16) are integrated in said cover (19) of said casing (17).

Abstract: The invention relates to a method of monitoring a temperature rise of a stator winding of a squirrel cage induction motor, in which method a stator current I of the motor is measured and the temperature rise of the motor at each moment is determined on the basis of this current I, when a rated temperature rise .theta..sub.N of the motor at a rated current I.sub.N, the rated current I.sub.N and a temperature rise time constant .tau. of the motor are known. The method comprises steps of determining the stator current I of the motor as discrete moments separated by .DELTA.t long time periods, determining the temperature rise .theta..sub.n(1) of the motor during one time period n from the equation ##EQU1## determining a cooling .theta..sub.n(2) of the motor during the same time period n from the equation.theta..sub.n(2) =.theta..sub.n-1 e.sup.-.DELTA.t/.tau.,where .theta..sub.n-1 is the temperature rise of the motor at the end of the preceding time period, and summing the temperature rise .theta..sub.

Abstract: A motor starter includes separable contacts interconnected between an alternating current (AC) power source and an AC motor for switching an AC load current which flows from the power source and through the separable contacts; a dual-slope analog-to-digital (A/D) conversion circuit for sensing the load current and generating a current value; and a microcomputer with a coil drive circuit for selectively opening the separable contacts as a predetermined function of the current value. The dual-slope A/D conversion circuit includes current transformers for sensing the AC load current and for selectively providing a received current therefrom, a current reference for selectively providing a reference current, a multiplexer for multiplexing the currents, and a class B preamplifier for amplifying and rectifying the multiplexed AC current.

Abstract: A driving circuit for driving a given load based on a load control signal is provided which includes a power transistor, a protective circuit, and a power transistor control circuit. The power transistor is responsive to the load control signal inputted to the driving circuit to be turned on for activating the load. The protective circuit is arranged to be activated by the load control signal to monitor a malfunction of the power transistor caused by overheating or overcurrent flow to restrict an operation of the power transistor. The power transistor control circuit is arranged to prohibit the power transistor from being turned on until the load control signal reaches a preselected level required for operating the protective circuit stably.

Abstract: The present invention relates to a resistor device for controlling a rotational speed of a motor which has no directional property and provides a convenient setting. A resistance unit is positioned which includes at least four connecting points connected to connecting terminals at an upper predetermined position of a housing, and a heat sink having at least four supporting legs is provided to form passing paths open in all directions on the housing. Also, the resistance unit is adhered on the heat sink through an insulating layer, a second heat sink corresponding to the first heat sink is adhered on the resistance unit through the insulating layer, and short-circuit means having a soldered portion to be fused at a predetermined temperature upon an overloading of the motor is provided between the resistance unit and any one terminal.

Abstract: An overcurrent protection device for a motor M with an overheat prevention function having a housing 10 with fixed contacts 16, 18 and movable contacts 24, 26. A first snap acting bimetallic element 20 in the device is responsive to heat from overcurrent conditions and a second snap acting bimetallic element 40 is responsive to heat from the temperature for the motor M. The movable contacts 24, 26 are controlled by the first bimetallic element to cause engagement or nonengagement with the stationary contacts 16,18. Coupling members 42, 44 contained in the housing engage both bimetallic elements 20, 40 and allow the first overcurrent bimetallic element 20 to snap independently of the second bimetallic element 40 while providing for snap action of the second bimetallic element 40 to also cause the first bimetallic 20 to snap.

Abstract: Control circuit for a refrigerating system, used in hermetic compressors, comprising first and second temperature sensors (61,62) and a current sensor (63) for the current drawn by the motor, said control circuit including a central processing unit (30), which instructs at least the selective closing of first and second driving switches (40,50), which are respectively connected with a main winding (11) and with a starting winding (12) of an electric motor (10), when the first temperature sensor (61) detects a temperature inside the refrigerating cabinet corresponding to a maximum value of an ideal temperature interval, previously informed to the central processing unit (30), the temperature of the motor (10) and the current drawn by said motor (10) being within their respective ideal operative values, previously informed to said central processing unit (30).

Abstract: A single phase induction motor includes a start winding, a run winding coupled in parallel with the start winding, a start switch, and a run switch. A control circuit is provided for selectively supplying voltage to the start and run windings. A current sensor is coupled to the control circuit and the start and run windings for estimating the temperature rise of the motor and turning the motor off if overheated. An alternating voltage having a plurality of 360.degree. cycles can be continuously applied to the run winding through the run switch. The alternating voltage is repetitively applied through the start switch to the start winding in the range of 45.degree. to 135.degree. into each respective one of the plurality of cycles and ending at approximately 180.degree. into each respective cycle and beginning in the range of 225.degree. to 315.degree. into each respective cycle and ending at approximately 360.degree. into each respective cycle until the motor is running at a speed close to synchronous speed.

Abstract: A motor control unit for protecting a motor against overload, short circuit and ground fault currents. The unit monitors the currents in each phase of the motor to provide values representative of each phase current. The unit also includes a contactor for opening and closing each phase, wherein the unit controls the contactor based upon the values representative of the phase currents. The contactor is opened where the phase currents exceed limits which indicate that either an overload, short circuit or ground fault situation exists at the motor. A magnetic trip circuit breaker can also be provided to operate in cooperation with the unit to provide instantaneous trip protection for current levels which are relatively high in relation to those for which the contactor is rated.

Abstract: A protection circuit for a permanent split capacitor motor includes a positive temperature coefficient (PTC) resistor in series with the auxiliary winding of the motor for protecting the auxiliary winding during normal operation. At a predetermined temperature anomaly due to over-current conditions in the windings, the PTC resistor will sharply increase its resistance to a point wherein no current will pass, effectively open circuiting the auxiliary winding from the power source, thereby protecting the windings from damage. A thermally responsive protector may also be used in conjunction with the PTC resistor for providing further over-current protection to both the main and auxiliary windings.

Abstract: A protective device for electric motors for protecting electric motors from high operational temperatures, has an element for determining an operational temperature of an electric motor and an element for automatically switching off of the electric motor when a predetermined limiting operational temperature is exceeded. The determining element is formed as electronic element for determining the operational temperature indirectly from an at least another operational parameter of the electric motor. The element for automatically switching off is formed as electronic element for automatically switching off of the electric motor.

Abstract: A synchronous machine is protected from closely spaced instances of excessive field current and an excessive volts/hertz ratio by a control system which models rotor and stator cooling to provide memory of recent periods of excessive heating. Maximum excitation limiting and volts/hertz ratio limiting modules in a microprocessor based automatic voltage regulator for the machine generate time delayed limit signals which override voltage feedback control when the respective parameters exceed threshold values. The limiters each increment a count when the associated threshold value is exceeded and generate the associated limit signal when a predetermined count is reached. The predetermined counts and the counting rates are selected such that the delay intervals are inversely proportional to the amount by which the threshold values are exceeded. The counts are decremented at a rate which models rotor and stator cooling when the respective parameters return below the threshold values.

Abstract: Microprocessor based apparatus for controlling an electrical load, such as a motor, includes an external capacitor for storing an analog equivalent of a digitally modeled heat state signal, such as the I.sup.2 t characteristic of the motor. The voltage on the capacitor decays to mimic motor cooling when the microprocessor is powered down with deenergization of the motor. The stored analog signal is updated by periodically converting the analog signal to a retrieved digital heat state signal which is compared to the latest calculated value of the heat state signal. If the retrieved value is below the present calculated value, an input/output port is set to a high output state to charge up the storage capacitor. If the retrieved value is above the calculated value, the port is configured as an output port with a low state to reduce the voltage on the capacitor.

Abstract: A device for motor and short-circuit protection in low-voltage plants includes a contact device (3) which is connected in series with a tripping circuit comprising two parallel-connected current branches. One of the branches comprises a first thermistor (1) serving as an overload protective means and connected in series with a second thermistor (2) serving as a short-circuit protective means. The second branch comprises a multi-turn excitation coil (4) which is adapted to influence the contact device (3) for opening thereof at an overcurrent. The resistivity of the two thermistors (1, 2) has a positive temperature coefficient in the temperature range in question. The first thermistor (1) may consist of a ceramic material or electrically conductive polymer composite. The second thermistor (2) consists of polymer composite with a extremely high content of electrically conductive filler and is, in addition, layered.

Abstract: A split-phase starter for an electric motor having a casing made up of a casing body and a lid secured to the casing body, the casing body having a first casing and a second casing, a relay contact mechanism being arranged in the casing body, and a positive temperature coefficient thermistor being arranged in the second casing.

Abstract: A device protects an electric load, such as a motor, from excessive current levels. The current flows from a source to the load through a switch and a primary winding of a current sensing transformer. The voltage across a secondary winding of the current sensing transformer is rectified to produce a voltage which is measured to determine the level of current through the load. The voltage across the secondary winding also powers components of the device. In a first mode of operation, current from the secondary winding is applied to charge a power supply capacitor. In a second mode of operation the level of the rectified voltage is sensed to produce a sample of the level of the current flowing through the load. From this sample the change in temperature of the load since a previous sample is calculated and used to derive the present load temperature. When the present load temperature exceeds a defined threshold level, the switch is opened to disconnect the load from the electricity source.

Abstract: An overcurrent detector realized by using a computer. The apparatus is provided with an overcurrent detector (5) which calculates the temperature rise .theta.(n) =K.sub.1 P(n)+K.sub.2 .theta.(n-1), based on a current (In) flowing in an electric machine, under the conditions that the machine has an electric resistance (r), the machine works in a known ambient temperature, the allowable temperature rise (.theta.(max)) of the machine is known, a first coefficient (K.sub.1) and a second coefficient (K.sub.2) are predetermined. The overcurrent detector (5) further compares the temperature rise (.theta.(n)) with a difference between the allowable temperature rise (.theta.(max)) of the machine and the ambient temperature at which the machine is used, and determines that the machine is in an overcurrent position, when the former exceeds the latter.

Abstract: An engine-driven power generating system comprising a bridge circuit section in which a low-frequency switching elements driven alternately by low-frequency drive signals, and high-frequency switching elements driven by high-frequency drive signals during the ON period of the low-frequency switching elements are connected in a bridge network, and an inverter circuit section having a drive signal supply circuit for supplying low-frequency and high-frequency drive signals are each supplied to the low-frequency and high-frequency switching elements that form a pair; the a-c voltage generated by an engine-driven a-c generator is converted into d-c voltage that is in turn converted into a predetermined level of low-frequency a-c voltage; characterized in that an emergency relay circuit device for protecting the engine-driven power generating system against abnormal operating condition.

Abstract: A multipole circuit breaker, for example, a three pole circuit breaker, can detect a condition when less than all of the phases are open circuited to trip the circuit breaker. This reduces the tripping time and hence risk of damage to the electrical load. The circuit breaker includes a thermal trip unit and a phase sensitivity assembly that is interlocked with the bimetals included with the thermal unit. The phase sensitivity assembly includes one or more levers, responsive to the deflection of a bimetal corresponding to the open circuited phase resulting from cooling action of a bimetal relative to the other bimetals. The relative displacement of the cooling bimetal is used to either trip or reduce the tripping time of the circuit breaker.

Abstract: An overload protective device to the disposed in an electric circuit serving to supply current to a load has a pair of fixed contacts provided inside of a case and an inversible disk-like bimetal of a curved shape having a pair of movable contacts capable of coming in contact with the fixed contacts, respectively. A shaft is fixed to the case at one end thereof and formed with a head portion at the free end portion. The shaft extends though a hole formed in the central portion of the bimetal. When the bimetal breaks, a circuit breaker breaks the electric circuit permanently to thereby prevent the load and the overload protective device from being burnt out.

Abstract: A split phase electric motor starter and protector are shown having a housing which receives a PTC starter switch and a motor protector and provides various wiring options for connecting the PTC switch and, if desired, a capacitor to a motor depending upon the particular requirements of an application. The housing optionally accommodates a capacitor support bracket.

Abstract: The present invention features a system and method for preventing overheating of a motor and/or power amplifier of a material handling vehicle by controlling the performance of the vehicle as a function of motor and/or power amplifier temperature. Temperature sensors are connected to the motor and power amplifier for determining their operating temperatures. A controller is connected to each temperature sensor and to the motor for controlling acceleration of the motor as a function of either or both temperatures, so that both the motor and the power amplifier will not overheat. In controlling acceleration of the motor, the invention provides a mechanism for changing acceleration by discrete steps or continuously according to a performance curve which may be linear or otherwise.

Abstract: In a drive control apparatus for an electric actuator to be activated under control of a changeover switch, the drive control apparatus including a power transistor arranged to supply therethrough the power to the electric actuator from an electric power source in response to operation of the changeover switch, a presumptive temperature of the power transistor is previously memorized and renewed in consideration with an increment of temperature change caused by consumption of the power when the electric actuator has been activated. The presumptive temperature is further renewed in consideration with a decrement of temperature change caused by lapse of time after the electric actuator has been deactivated. The power supply to the electric actuator is permitted only when the presumptive temperature is lower than a predetermined value. When the presumptive temperature becomes higher than the predetermined value, the power supply to the electric actuator is prohibited.

Abstract: An operation control circuit for pump motor which is made such that driving condition of pump motor is checked and then when its driving condition is abnormal than driving of the pump motor can be stopped.The operation control circuit includes a pump environmental temperature detecting and heater energizing section, an overload and no-load detecting section, an overload driving count section, a no-load driving count section, latch sections, a reset section, a pump motor driving control section, and an operating state display section.According to the invention, using life time can be extended by preventing overload and no-load operation of pump motor, and freezing break down of pump motor can previously be prevented, and opening and closing noise of switch can be reduced.

Abstract: A microprocessor-based relay system is used in combination with relay contactors and a control circuit therefor to protect an electric motor from overload currents in addition to phase faults, ground faults, load losses, and load jams. The microprocessor is provided with a data base comprising thermal characteristics of the motor during heating and cooling. The heating data comprise current versus time curves stored as a look-up table for which each data point represents a thermal limit, i.e., the maximum time the motor is permitted to operate at a particular current level. The cooling data comprise motor cooling rates. Phase currents are sampled at preselected fixed time intervals during a predetermined period thereof, and an average motor current value is calculated therefrom. A thermal sum, which is initialized at zero upon first starting the motor, is adjusted depending on the average motor current value relative to a predetermined overload current value.

Abstract: Electrical terminal pins (start, main and common) mounted in a glass header to provide electrical connection to a compressor motor are shown with a motor protector disposed on one of the pins in such a fashion that opposite-direction-oriented right angle female flag quick connectors are required for the start and main terminals, thereby avoiding the possibility of miswiring the terminal pins. The opening temperature of the motor protector is adjustable and the protector has a fail safe mechanism to avoid subjecting the motor to overtemperature conditions.

Abstract: A motor winding system having a main winding and a start winding circuit with a start winding and a PTC resistor in series therewith wherein the resistor is electrically removed from the circuit at a predetermined time after motor starting and remains in this state until motor shut off. The start winding circuit also includes a bimetallic switch in series with the resistor and a series circuit of a capacitor and an electromagnet in parallel with the resistor and switch. At motor start up, current from the main power source is applied across the main winding and the start winding circuit heats up the resistor and causes an increase in the resistance thereof. Also, current through the switch and PTC heat causes the bimetallic element to snap or move when it has reached a predetermined temperature to open the start winding circuit.

Abstract: Stall current levels are determined according to measured peak currents occurring immediately after the energization of a motor. By utilizing a fractional value of the determined peak current value, the stall current is determined each time the motor is energized to compensate for variations in current flowing in a motor at different ambient temperatures.

Abstract: Thermal overload of a motor is avoided by measuring temperature and, when a limit temperature is exceeded, reducing the phase "window" within each power cycle during which the motor is energized. The limit temperature is sensed by a temperature sensor which is warmed either by heat conduction through a cooling body or by an air stream from the motor. The overload protection apparatus requires no measuring resistance in the load circuit.

Abstract: An electrically driving system for the rearview mirrors, wherein the incorporated motors are rotated normally or reversibly in response to the operation of a operational switch, thereby erecting or folding the mirror bodies. The system comprises a momentary operational switch, a relay circuit, a group of limit switches for cutting off the relay circuit and motor circuit respectively by detecting erected and folded positions of the mirror bodies, and a circuit for judging a folded state. When the operational switch is pushed, any folded mirror is detected within delay time of the circuit for judging a folded state. And only when both of the left and right mirror bodies are in the fold positions, the erecting relay is actuated to rotate the motors in the erecting direction.

Abstract: An apparatus for starting and controlling a motor. The apparatus includes means for monitoring the load current values in each phase of a motor. These means can include an apparatus such as a current transformer. The apparatus utilizes a circuit for modeling a motor and estimating the temperatures of the motor's windings and housing. THe circuit preferably is defined by a programmed microprocessor. The estimated temperatures are based on the load current values and time. These estimated temperatures are then compared to allowable limits and, based on the comparison, the motor is either stopped or allowed to run.

Abstract: A method and apparatus for controlling the operation of an oil well pumping unit in which the prime mover is a polyphase AC electric motor. The system comprises means for generating a plurality of signals representative of motor fault parameters including a motor winding overtemperature fault, undervoltage fault, and a phase imbalance fault. Upon occurence of a fault, a contactor in the motor supply leads is open to shut down the motor. After such shutdown because of undervoltage or phase imbalance faults the fault parameters are continuously scanned and once the fault has been cleared the motor is restarted. Where motor shutdown occurs because of an over temperature fault, the motor is maintained in a latched off shut down condition until an operator implemented reset occurs. An accessible counting memory is provided having separate registers for each of the fault conditions.

Abstract: A motor protector includes a case having an open end, a terminal plate secured to the case and having a pair of fixed contacts, a disc-shaped bimetal supported in the case and having a pair of movable contacts engaged with and disengaged from the fixed contacts respectively, a temperature-sensitive switch disposed so as to close the open end of the case and sensing the temperature of a sensed object to be turned on when the temperature thereof reaches a predetermined value, and a heater disposed in the vicinity of the bimetal and connected in series to the temperature-sensitive switch.

Abstract: A dynamoelectric machine includes a stator assembly having one or more sets of electrical windings. Apparatus for electrically interconnecting external electrical leads, a thermal protector and ends of each set of windings includes a protector block for commonly connecting one end of at least one winding set with the thermal protector. The thermal protector is housed in the protector block. A terminal block interlocks with the protector block to hold the thermal protector in place. An electrically conductive arm of the thermal protector extends through the terminal block to effect connection of the thermal protector with an external lead. The terminal block also provides for connection of the other end of each winding set with another external lead.

Abstract: A motor protector and starter particularly suited for refrigeration compressor motors are mounted in the recess of a first housing portion with their resilient female sockets disposed in alignment with a pin receiving aperture. Leads are attached to terminals of the motor protector and starter components and directed through lead receiving apertures in the side wall of the first housing portion. A second housing portion is then snapped onto the first housing portion to provide a combination housing which can be installed on a compressor in a one-step on-line operation.

Abstract: An electronic control for regulating the operation of a two-speed motor in a heat transfer system such as a heat pump or air conditioner. The control receives high and low demand signals from a thermostat and a motor unit operates at high and low speeds in response to, respectively, high and low speed signals. The control includes an initial timer, high and low speed operators, and a speed change delay. The initial timer detects the occurrence of a demand signal from the thermostat, counts a predetermined period of time, and responsively issues an initial timing completion signal. The high and low speed operators detect the timing completion signal as well as either a high or low thermostat demand signal. One of the operators then responsively issues either a high or low speed signal to the motor unit. The motor unit accordingly operates at a high or low speed. The speed change delay detects the change in a thermostat demand signal from a high to a low state or a low to a high state.

Abstract: A changeover contact-making apparatus with interlocking member and module of protection protected against overcurrents is provided. In a same case, two contact-making systems and coil switches are disposed on each side of a median plane PP' in which the interlocking member is placed. In one of the case inner volumes defined by the plane PP' are placed a single protection module, a tripping mechanism and the respective connection terminals.

Abstract: An electric motor armature current control circuit includes an electric motor with an armature in series with a protective device comprising a pair of polymer PTC elements connected in electrical series with the motor armature windings and in electrical parallel and thermal contact with each other. The first polymer PTC element, a temperature compensating element, has a very low cold resistance and a trip temperature higher than the maximum expected ambient temperature to which it is to be exposed in motor operation and generates heat in motor operation to trip to a much higher resistance and become self-regulating at that trip temperature. The second polymer PTC element is maintained at least at the trip temperature of the first through thermal contact and has a lower resistance at that temperature than the cold resistance of the first. Its trip temperature is higher so as to be reached only with excessive armature current.

Abstract: A motor-driven power steering system for a vehicle capable of preventing a motor-related element such as a motor itself, power elements for controlling power supply to the motor or the like from being damage due to an abnormal temperature rise or overheating thereof, thereby substantially avoiding or reducing resultant unsureness or instability in the operator's steering feeling upon change in steering mode as well as improving safety in steering operation. The motor is operatively connected with a steering rack and energizable by a power source for power assisting the steering motion caused by the operator through a steering wheel. A temperature sensor detects the temperature of the motor-related element. An electromagnetic switching clutch is interposed between the motor and the steering rack for selectively establishing and interrupting the transmission of power assisting force from the motor to the steering rack in accordance with the travelling speed of the vehicle.

Abstract: A control device for supplying current to electrical appliances and particularly appliances having single phase capacitor start motors wherein the control device includes a changeover switch which is mounted between a source of power and the appliance motor and which changeover switch includes selectively operated components for controlling the power supply to the appliance motor or to terminate the power supply thereto. In one embodiment of the invention, a second circuit is provided intermediate the power source and the appliance motor for detecting the amount of current flowing in the circuits so as to insure connection of the starting capacitor of the motor, braking of the single phase motor when power is terminated and to provide an indication of overcurrent in the motor.

Abstract: A motor-driven power steering system has a steering mechanism for interconnecting a steering wheel and a steerable wheel. An electric motor applies a steering assistive force to the steering mechanism. A plurality of frictional elements are each provided with a lubricating material having a temperature-dependent viscosity. The motor-driven power steering system also includes a steering torque detector for detecting a steering torque applied by the steering wheel through the steering mechanism and for generating a signal indicative of the steering torque a temperature detects for detecting the temperature of at least one of the frictional elements and generates a signal indicative of the temperature. A motor control signal generator generates a motor control signal based on at least the signals from the steering torque detector and the temperature detector. A motor driver controls the electric motor based on the motor control signal.

Abstract: A motor protection relay is taught which determines effective and RMS values of current on a cycle-by-cycle basis by measuring three-phase currents at 10.degree. intervals in a line cycle and then determining the positive and negative sequence components thereof by storing the accumulated information in a memory. In order to increase the dynamic range of the sensing apparatus, only the negative half wave of each current is sensed and the positive half wave is reconstructed by finding the 180.degree. phase shifted equivalent thereof in the negative half wave.

Abstract: A terminal block and overload protector for a compressor assembly for connection to the terminal pin assembly of a compressor located on the inside wall of a compressor casing. The assembly includes a housing with three apertures therein into which three of the terminal pins are disposed. Electrical connector clips are disposed in the housing for connection to the terminal pins. The housing also includes a space in which a motor protector is secured. The motor protector has two terminal pins which are secured to slip-on quick-connect terminals. The motor protector housing has a third connector clip secured thereto. Each of the three connector clips has a knurled inside surface for gripping and retaining of the respective terminal pins.

Abstract: A motor protection relay is taught in which the temperature of a rotating rotor is inferred from the current flowing in the lines which supplies the motor and from resistance temperature detection devices in the stator of the motor. By utilizing a periodic predictable established interrupt routine within the software which controls the microprocessor which in turn controls the monitoring device the time based model for inferring rotor temperature can be freed of a requirement to use a fixed sampling time rather the time for calculations can be variable. The total number of counts that particular interrupt routine has taken place will be factored into the calculations to make the calculations accurate. The thermal model is further improved by expressing it in terms of current squared times time so that the component portions of the equation which represents the thermal model can use accumulator inputs into which values of line current squared have been previously placed.

Abstract: A power unit for a battery-driven toy containing a battery power source for energizing a driving means through a power switch and a controlling circuit is disclosed, in which the controlling circuit comprises a circuit element for controlling said driving means and its movable operative contact, said circuit element being provided with a thermo-switch and a reset circuit for setting said movable operative contact into an OFF position through said thermo-switch.

Abstract: This invention relates to a compact protector which is used to prevent the over-heat of a compact motor used in heat generating appliances such as a hair dryer or electric washing machine. The protector incorporates therein an excess current prevention portion utilizing a bimetal and an excessive temperature rise prevention portion utilizing a temperature fuse. The protector opens an electric path by the double safety devices.

Abstract: A device providing protection against over-currents in the windings of an electric motor having a rotor (3) and at least two windings (1, 2) comprises at least two parallel thermistors (17, 18) each mounted in series with at least one motor winding (1, 2).

Abstract: A motor protection relay is provided which is programmable to limit the number of starts which are allowed in a given interval of time. In accordance with the algorithm associated with the relay microprocessor for controlling the starts per time, old starts which no longer fall within the same time constraint set by the operator or user are discarded and the time constraint is updated according to the next oldest start time.