Abstract: The switching on and switching off of an air conditioner is primarily determined by signals which are supplied by a temperature controller. However, operating conditions are present wherein the temperature controller supplies the signal "on" but that the operation of the air conditioner is nonetheless unwanted so that the torque of the engine can be available for driving the vehicle. The fulfillment of special conditions for switching off and again switching on the air conditioner are therefore investigated when temperature switch-on conditions are fulfilled. According to the method of the invention, the air conditioner is switched off when the accelerator pedal position exceeds a switch-off threshold value and the difference between the actual permissible full-load quantity and the actual correct idle quantity is less than a predetermined minimum difference.

Abstract: A method of controlling compressor current in an air conditioning system having a variable speed compressor which has a predetermined current limit. The actual compressor speed is sensed and compared to a requested predetermined compressor speed. Corrective steps are taken to reduce compressor load if the sensed compressor speed falls below a requested predetermined compressor speed.

Abstract: An engine control system of an automotive engine cooperates with an engine driven air conditioning system which is restrictively driven when the engine operates in a predetermined operating condition. The engine control system includes a pressure sensor to detect an atmospheric pressure at which the engine operates. The predetermined condition is changed according to the atmospheric pressure.

Abstract: A memory stores, in advance, at least a first V/F pattern corresponding to an air conditioning load and having reference voltage and frequency characteristics, and a second V/F pattern having voltage and frequency characteristics lower than those of the first V/F pattern in a starting region of a variable-capacity compressor for driving a refrigeration cycle. A detector detects an over current supplied to an inverter for driving the compressor. A controller stops the compressor through the inverter when the detector detects the over current, and restarts or holds the compressor through the inverter in accordance with the detection count of the over current. The compressor is restarted with the first V/F pattern from the memory when the detection count is smaller than a first predetermined count, and when the detection count reaches a second predetermined count larger than the first predetermined count.

Abstract: An air-conditioner comprises a refrigerating circuit having a compressor, a condenser, an expansion device and an evaporator which are connected by suitable refrigerant conduits. An electric current path for making a current flow through the compressor includes an AC power source, to which a current transformer is coupled, and an output of the current transformer is converted into a DC voltage which is then given as a (+) input of a comparator. A reference voltage is given to a (-) input of the comparator. When the DC voltage exceeds the reference voltage of the comparator, the high level is outputted from the comparator. When the high-level output from the comparator persists for three seconds, the compressor is stopped forcedly and a three-minute timer is turned on. After a lapse of three minutes, the flow of the current through the current path of the compressor is resumed. Thereby, a lightly locked state is removed.

Abstract: A compressor controller of a refrigerating device comprises a power supply voltage detecting device, a voltage comparing device, and a compressor driving device. When the temperature in a compartment of the refrigerating device rises and the compressor is required to be driven to cool the compartment, the power supply voltage detecting device detects the voltage of the power supply which feeds power to the compressor. The voltage comparing device compares the power supply voltage with a reference voltage. When the power supply voltage is no lower than the reference voltage, the compressor driving device starts the compressor. The compressor controller also includes a compressor starting condition detecting device, a compressor halting device, and a voltage compensating device. The compressor starting condition detecting device detects the starting condition of the compressor by detecting the voltage or the current which is fed to the compressor by the power supply.

Abstract: In a variable speed air conditioning system driven by an electronically commutated DC motor, the large DC capacitor associated with the compressor motor drive discharges to the normally AC powered compressor oil sump heater upon the loss of AC power to the system.

Abstract: The present invention aims at securing a steady air conditioning capacity regardless of any fluctuation in speed of an engine in a car air conitioning apparatus using the engine as a power source, which comprises a generator driven by a main engine, a compressor provided with a driving motor, a condenser, an expansion means, an evaporator, a condenser blower, an evaporator blower, and a power controlling means for controlling a power generated by the generator and feeding it to the compressor, condenser blower and evaporator blower.

Abstract: A sliding-vane rotary compressor includes a first control valve responsive to the pressure in a low pressure chamber for adjusting the rate of communication between a high pressure side and a low pressure side, and a second control valve operative in the same manner as the first control valve under the control of an external signal. With this construction, an optimum displacement control of the compressor is achieved. Also disclosed is an apparatus for controlling a variable displacement compressor, in which a solenoid valve is controlled depending on internal and external thermal load conditions of the compressor for selectively blocking fluid communication between high and low pressure sides.

Abstract: To reduce the running cost of an MRI apparatus, power supplied to a normal conductive coil from a pre-regulator is reduced in an idling mode. This reduction in power also reduces the heat generated in the normal conductive coil and a shunt resistor. A computer controls a cooling unit according to the amount of the heat reduced in order to reduce to flow rate of a cooling medium. In this manner, the temperatures of the normal conductive coil and shunt resistor can be maintained at constant levels. Further, if a current value is set to maintain the temperatures of the normal conductive coil and shunt resistor at the constant levels only by natural heat radiating, circulation of the cooling medium can be stopped.

Abstract: A system for restoring a set temperature in a refrigerator after power has been cut off. The refrigerator includes a compartment for which plural set temperatures can be selected. The refrigerator is provided with a temperature detecting device for detecting an interior temperature of the compartment, a power restoration detecting device for detecting the restoration of power after a power cutoff occurs, and a microcomputer. The microcomputer determines the appropriate set temperature when power is restored in response to receiving a temperature detection signal from the temperature detecting device. The microcomputer stores the determined set temperature and controls the temperature in the compartment in accordance therewith.

Abstract: Disclosed is an inverter control circuit in an air-conditioner, in which the parameters for controlling the inverter are changed over depending on the open air temperature, the cooling/heating operation mode of the air conditioner, taking into consideration the fact that the allowable maximum current of semiconductor devices constituting the inverter depends on the cooling capability, and hence on the season. In the heating operation in winter where the open air temperature is low, a larger current can be caused to flow in the inverter.

Abstract: An air conditioning apparatus to which an operating current is supplied through a plug includes a compressor and a detector for detecting one of the temperature level of the plug and the operating current level flowing through the plug. When the detected level of the plug is above a first upper limit during a predetermined time after the start of the compressor, the output level of the compressor is reduced for decreasing one of the temperature level of the plug and the operating current level flowing through the plug below the first upper limit. When the detected level of the plug is above a second upper limit below the first upper limit after the predetermined time, the output level of the compressor is reduced for decreasing one of the temperature level of the plug and the operating current level flowing through the plug below the second upper limit.

Abstract: A control and method for varying the capacity of a centrifugal chiller system used to cool a liquid to a setpoint temperature. The control permits the user to select the setpoint, the control gain, and two variables that determine a first deadband and a second relatively wider deadband about the setpoint. If the absolute value of the difference (error) between the actual fluid temperature and the septoint is increasing, the control uses the first deadband, and conversely, if the error is decreasing, it uses the second deadband to vary chiller capacity. The control also permits the user to select a limit for various operating parameters associated with protective shutdown of the system to avoid catastrophic failure, and adjusts the chiller capacity according to one of two predefined functions of the deviation of the operating parameter from its limit, dependent on whether that deviation is greater or less than a predefined deadband.

Abstract: This controller is used for controlling a centrifugal compressor along its path of minimum power consumption while avoiding a surge condition. It is especially useful in a refrigeration system having a variable speed centrifugal compressor with adjustable inlet guide vanes. In such an application, the controller opens the inlet guide vanes enough to satisfy the cooling demand and then, to minimize power consumption, reduces the speed of the compressor while further opening the vanes (compensating for the reduced speed) until either the inlet guide vanes are fully open or an impending surge condition is detected. The onset of a surge condition is detected by monitoring motor current fluctuations. When fluctuations above a predetermined amplitude occur in excess of a predetermined frequency, the controller determines that a surge is impending.

Abstract: A refrigeration apparatus includes a compressor, a condenser and a eutectic plate adapted to be mounted in the refrigerated space in place of, or in heat-conducting relation with, cooling coils. The compressor is of a type operated by a battery which is recharged by a generator. In turn, the generator is powered by any convenient external power source, such as an internal combustion engine. The refrigeration apparatus also includes a control device which senses the voltage at the battery terminals, thereby determining whether or not the engine is running. The control device chooses between two different cooling levels. A low (warmer) cooling level is chosen if the engine is not running. A high (cooler) cooling level is chosen when the motor is running.

Abstract: Disclosed are refrigeration system control systems and methods for compressor motor protection and defrost control. The disclosed systems and methods are generic in the sense that they are self-calibrating and so may be employed in a variety of different air conditioner or heat pump models of different sizes and capacities, without being specifically tailored for a particular model. The disclosed systems and methods sense loading on the compressor and evaporator fan motors, preferably by sensing the voltage across the capacitor-run winding of an AC induction motor and normalizing with respect to line voltage. The self-calibrating capability is implemented by taking advantage of the changing loads as a function of time on both the compressor and fan motors during both normal and abnormal operation of a refrigeration system. In overview, a reference value of motor loading is established for each motor at certain times during an ON cycle.

Abstract: A control system for controlling the capacity of a lead compressor of a refrigeration system having a lead and lag compressor when the lag compressor is in surge. A microcomputer system receives electrical input signals indicative of the lead and lag motor currents and closes the inlet guide vanes of the lead compressor when the lag compressor percent motor amps are below the lead compressor motor amps by more than a selected percentage for a specified period of time.

Abstract: A control system for engine-driven vehicle accessories generates sets of values representing a recent history of the engine loading and of the operational status of the accessories. History factors are derived from the sets of values. The accessories are controlled as a function of sensed parameters and of comparisons between the history factors. The sets of values are periodically updated.

Abstract: In a hermetic compressor there is provided a resilient retainer member adapted to removably secure a thermal overload protector relative to the compressor casing. The overload protector is arranged in a housing which is adapted to engage the upper wall of the casing. The retainer member includes one end portion dimensioned to engage the housing whereby downward pressure on the retainer member secures the overload protector relative to the casing. The overload protector housing is formed to include a pair outwardly projecting leg members. A slot formed on one of the legs aligns with an opening in the other leg are engageable by a tool which is employed to exert an external force on the housing sufficient to allow removal and replacement of the thermal protector housing relative to the retainer member.

Abstract: In an air conditioner separated into an indoor unit and an outdoor unit, a control circuit comprises a three-phase power source connected in common to the indoor and outdoor units, and a signal line led out from two phases of the power source. A contact of an electromagnetic relay energizing a compressor of the air conditioner is connected on the portion of the signal line in the indoor unit in series with a current sensor sensing the current flowing through the signal line, and a contact of a protective relay protecting the compressor is connected on the portion of the signal line in the outdoor unit in series with the electromagnetic relay. A first controller is disposed in the indoor unit for controlling on-off of the relay contact of the electromagnetic relay, and a second controller is disposed in the outdoor unit for energizing the protective relay contact thereby controlling on-off of the compressor.

Abstract: A heat-pump type air conditioning apparatus comprising a compressor, a condenser, a throttle member, and an evaporator, which constitute a refrigerant circulation circuit, and an unloading circuit is connected to the compressor to carry out a load reduction control. The air conditioning apparatus further comprises a detector for detecting load condition applied on the compressor and generating a signal representing the detected load condition, and a detector for detecting a condition of a power source for driving the compressor and generating a signal relating to the detected condition of the power source. A control unit is operatively connected to the detectors for controlling the switching of the air conditioning apparatus from a normal, full-capacity operation to a controlled, reduced capacity operation or vice versa in accordance with the signals regarding the detected load and the detected condition of the power source.

Abstract: A method and control system for protecting an electric motor driven compressor in a refrigeration system are disclosed. The refrigeration system operates to satisfy a load placed on the system and the refrigeration system compressor is turned off when the load is satisfied and the refrigeration system is providing excess capacity. When the compressor is turned off due to excess capacity, current flow to the electric motor driving the compressor is sensed and the refrigeration system is shut down if the sensed current flow is abnormal. In this manner, the compressor and the electric motor driving the compressor are protected against restarting under unfavorable operating conditions which could unduly wear the compressor motor and/or the compressor.

Abstract: An arrangement and method of controlling optimum chilled water temperature supplied to a process by a pump, the water being chilled by coolant in a coolant cycle having a compressor and a load valve, comprises first and second sensors for sensing a supply and a return temperature to and from the process. A value is obtained for the amount of work done by the pump and the compressor with that value as well as the supply and return temperature values being supplied to a supervisory control. The supervisory control operates to generate a reference temperature which is a function of the supply temperature but which is either above or below the supply temperature depending on a ratio between the difference in work and a change in the difference between the supply and return temperatures. When the ratio is about zero this indicates the difference between supply and return temperature is at an optimum and the reference temperature is the same as the supply temperature.

Abstract: A fluid-driven pump directly converts fluid kinetic energy into displacement of a second fluid against a pressure differential. In one form of the invention, a wind turbine is coupled via a rotary shaft crank to a reciprocating piston in a large-displacement, double-acting compressor cylinder. In a preferred mode, a refrigerant gas is compressed to accomplish heat pumping and refrigeration. Timed compression-relief valving controls the time that the wind turbine is coupled to the fluid load to maintain maximum power transfer within useful operating limits of source and load. An electronic control circuit senses selected parameters to compute the desired duty cycle and provide an energizing signal to a pair of solenoid relief valves such that the optimum duty cycle is selected for maximum power transfer.

Abstract: An automobile air conditioner has a refrigeration cycle composed of a compressor, condenser, liquid tank, orifice means and an evaporator, as well as mechanical parts such as a radiator and radiator fan associated with the condenser and a blower combined with the evaporator. The compressor is operatively connected to the automobile engine through a connecting means so as to be driven by the engine selectively in accordance with the temperature in the passenger's compartment. According to the invention, the compressor is driven when the automobile is being braked, even if the temperature in the compartment is lower than a set temperature, to make an efficient use of the kinetic energy possessed by the mass of the automobile. The cold energy generated during braking is suitably stored and is released into the passenger's compartment as desired.

Abstract: A motor control system includes a motor system having a pole-amplitude-modulated (PAM) motor, a motor breaker, and a speed switch coupled between the motor breaker and the PAM motor. The PAM motor is coupled to a fan in an exhaust duct having a controlled damper for controlling air flow therethrough. A control system step logic sequencer includes means responsive to permissive signals for providing in sequence control signals to the motor breaker and speed switch in response to confirmation signals received from the motor breaker, the speed switch and the PAM motor.

Abstract: A device at a heating or cooling unit such as, for example, a heat pump where the energy carrier is a substance, the volume of which varies substantially with the temperature, for example freon.At such a unit, which comprises condenser (1,2), evaporator (1,2) and compressor (3), and where the compressor is driven by an electric motor (18), according to the invention a tank (21) is provided to contain said substance (22) and is connected to the suction side (19) and, respectively, pressure side (20) of the compressor (3) by two respective conduits (23,24), each of which is provided with an electrically controlled valve (25,26) for closing and, respectively, opening the conduit in question.

Abstract: An automatic car-cooler clutch control apparatus such that the compressor can forcedly be engaged with the engine when a predetermined period of time has elapsed after the compressor is disengaged or when the vehicle speed reaches a predetermined value, in addition to when a vacuum pressure within the intake manifold is more than a predetermined value, that is, a relatively light load is applied to the engine. The automatic car-cooler clutch control apparatus of the present invention comprises a timer or a speed indicator including one or two switch circuits for energizing the clutch relay to engage the compressor with the engine, regardless of a vacuum pressure within the intake manifold, in addition to a vacuum pressure switch and a vacuum pressure chamber communicated with the intake manifold.

Abstract: The temperature of a product which is being chilled in a blender by introducing carbon dioxide in solid and gaseous form into the blender is controlled by sensing the power drawn by the drive motor coupled to the impeller. The power drawn by the motor is sensed and analyzed and, upon reaching a predetermined value, the introduction of CO.sub.2 into the blender is terminated. As the product is chilled by contact with CO.sub.2 in the blender, the viscosity of the product will increase, which in turn, increases the power drawn by the motor. Variations in line voltage supplied to the motor and changes of the initial temperature of the product being chilled do not affect the final temperature to which the product may be accurately chilled.

Abstract: An automatic chiller control is disclosed for providing a temperature sensitive load limit compressor control on a cooling water system, such as is used in buildings for air conditioning. The controller operates across at least one motor driven compressor and operates to adjust the vane inlet to a typically centrifugal compressor. Control is provided in discrete steps responsive to changes in cooling water temperature as the water typically returns from a building. The control when operated in the automatic position starts the chiller at minimum possible power consumption. Increasing load or unload of the chiller is provided in incremental steps (for example 5% of full load) at preselected time intervals (for example 10 minutes) which are typically adjustable to any other desired time span. The control seeks the required motor power output without waste of power.

Abstract: A circuit interrupting apparatus and method for a blower having a resistance heater in the air stream of the blower for cooling of the resistance heater and a fuse surrounded by the resistance heater to cause the fuse to blow through heat of the resistance heater when the air stream stops flowing and the amperage of the circuit is not sufficient to blow the main fuse of the system.

Abstract: The cooling system includes a cyclically operating cooling-medium compressor driven by the vehicle engine. At low to medium engine speeds, corresponding to speeds from idling to city-driving speeds, the cooling system develops a cooling power sufficient to satisfactorily cool the interior of the passenger compartment. At higher engine speeds, corresponding to highway travel, the cooling power developed by the cooling system is automatically decreased by automatically decreasing the per-cycle volumetric throughput of the cooling-medium compressor. The automatic decrease is effected in automatic response to the reaching of a certain engine rpm or a certain condensation pressure in the condenser of the cooling system. In the illustrated embodiment, the compressor is a sliding-vane compressor, and the per-rotation volumetric throughput thereof is decreased by arresting certain ones of the vanes in the retracted position.

Abstract: A magnet is fixed to a rotor shaft and a ferromagnetic cup which is magnetically coupled to the magnet is urged opposite to the direction of rotation of the rotor shaft by a spring. An occluder plate is fixed to the cup and is movable into alignment with a fluid inlet to block the same. As the speed of the automobile and thereby the compressor rotor shaft speed increase the magnetic fields resulting from eddy currents induced by the magnet in the cup increase and the degree of magnetic coupling thereby increases so that the cup is rotated further against the force of the spring causing the occluder plate to block the inlet to a greater extent so that the compressor output and thereby the cooling effect of the air conditioner are maintained at a substantially constant value.

Abstract: The compressor motor of an air conditioning unit is operatively coupled to a A.C. line through a solid state electronic switch. Triggering signals for the switch are supplied from an oscillator circuit which is D.C. isolated from the switch, the trigger signals being coupled via transformer coupling. The oscillator is in turn thermostatically controlled in accordance with the cooling demand. The oscillator is also interlocked via a photocoupling device with an electronic timer circuit and with an undervoltage sensing circuit. The timer imposes a mandatory minimum delay between successive energizations of the compressor motor thereby permitting time for pressures in the refrigeration circuit to subside. The undervoltage sensing circuit is responsive to an electrical brownout condition for shutting down the motor should an electrical brownout condition occur. The undervoltage detector also contains a blackout detector section which shuts down the motor more rapidly during more extreme undervoltage conditions.

Abstract: A combination high pressure relief valve and magnetic clutch disconnect switch for an air conditioning compressor which utilizes an automatically resetting valve member. The escape of pressurized refrigerant under control of the relief valve pressurizes the interior of a cap member on the end of the relief valve and thereby disconnects the ground circuit portion of the electromagnetic compressor clutch. This renders the system inoperative until the cap can be replaced and the original cause of the high pressure is determined and remedied.