Abstract: The invention provides a rotor for an electrical motor, a tool for making a rotor core and a method of making the rotor. The rotor could be incorporated e.g. in a line-start motor and comprises a squirrel cage and magnet located in a rotor core. The magnets are, in one end of the rotor, secured by an end plate with apertures which are larger than the magnet openings, and the end plate is indexed relative to the magnet slots such that a first portion of openings into the magnet slots is in communication with the aperture and such that a remaining, second, portion of the magnet slots is covered by the end plate. In one aspect, the end plate forms an integrated part of the rotor core and comprises openings cooperating with conductor slots to form through-going passages for conductors of the squirrel cage. In that way, the end plate is held in a completely fixed position by the squirrel cage which is moulded directly onto the core and into the conductor slots.

Abstract: A method for starting a battery driven motor, wherein an input voltage is measured continuously. In case the input voltage becomes smaller than a predefined minimum voltage the attempt to start the motor is stopped and the maximum permitted current level to be supplied from the battery to an electronic unit of the motor is lowered before the next attempt. This is repeated until the input voltage is larger than the minimum voltage and the motor is no longer in start-up mode. The method protects the battery from collapsing. The method is suitable for starting battery driven motors for driving compressors. The number of attempted start-up sequences may be counted and on the basis of this it may be determined that the battery is weak or that the wiring is misdimensioned. Furthermore, a control system for controlling starting of a motor.

Abstract: Motor start circuit for an induction motor, particularly a single phase AC induction motor, with a main winding (4) and an auxiliary winding (5) having two end connections (6, 7) supplied with current, mainly AC, via current supply connections (34, 35), and with a start circuit device (15) serving the purpose of stopping the current flow through the auxiliary winding (5) after the start of the motor, and being connected via a conductor (18) to a control device (20) connected between the current supply connections (34, 35), and with a preset timer device interacting with the start circuit device (15) to stop the current flow through the auxiliary winding (5), as soon as a predetermined period after the start of the current flow has lapsed.

Abstract: The invention concerns a suction muffler for a hermetic refrigerant compressor with a housing having an inlet and an outlet and limiting at least one muffling chamber, and a gas supply channel located in the muffling chamber between the inlet and the outlet. It is endeavoured to prevent too much oil from remaining in the refrigerant gas flow. For this purpose, the gas supply channel forms a throttling path and ends in the muffling chamber, and that in the area of the inlet of the gas supply channel an oil extraction opening is located, which ends in the muffling chamber.

Abstract: The invention concerns a compressor crankshaft, particularly a refrigerant compressor crankshaft (1) and a method for manufacturing such a crankshaft, with a shaft element (2), a crank pin (9) located eccentrically to the shaft element and a transition element (7) between the shaft element (2) and the crank pin (9). The purpose of the invention is to keep the manufacturing costs low. For this purpose, it is ensured that along its circumference the transition element (7) has at least one first reference point (20) and one second reference point (21a, 21b), with which the transition element (7) can be positioned in a holding fixture (25) of a working machine.

Abstract: The invention concerns a rotor arrangement for an electrical drive motor of a compressor, particularly a refrigerant compressor, with a rotor having a rotor lamination of stacked sheet plates, and a shaft, which is inserted in an axial recess of the rotor lamination and is unrotatably connected with the rotor lamination, the recess being formed by openings in adjacent sheet plates. It is endeavoured to simplify the manufacturing of such rotor arrangements. For this purpose, it is ensured that openings of different sizes are provided in the sheet plates, at least two sheet plates forming a first group, each having an opening, which is smaller than the cross-section of the shaft, the remaining sheet plates forming a second group, each having an opening, which is larger than the cross-section of the shaft.

Abstract: The invention concerns a motor starter circuit for an induction motor, particularly a single-phase AC induction motor, with a main winding (4) and an auxiliary winding (5) supplied with current, particularly AC, via current supply connections (24, 25), and with a starter switch arrangement (15), which serves the purpose of interrupting the current flow through the auxiliary winding (5) after the start of the motor, the starter switch arrangement (15) interacting with a measuring arrangement serving the purpose of measuring the voltage across the auxiliary winding (5).

Abstract: The invention concerns a valve plate for a reciprocating compressor, the valve plate being made as a sintered part, having on at least one valve plate surface at least one valve seat surface (30, 31) being worked after sintering. In order to simplify the manufacturing of the valve plate, the valve plate surface has at least one defined area portion with a relatively uneven surface and at least one defined area portion with a relatively even surface.

Abstract: A cooling medium compressor arrangement is comprised of a compressor, a control mechanism electrically connected with the compressor, and a gas sensor, and the safety of the arrangement is improved by arranging the control mechanism and the gas sensor in a common housing.

Abstract: The invention concerns a starter for a line start electric motor having at least one main winding (4) and at least one start winding (12) and which start winding is connected in series with a run capacitor (14) with which a start capacitor (17) and a PTC-thermistor (19) are connected in parallel. In order to make a simply constructed starter for a line start electric motor the start capacitor (17) and the PTC-thermistor (19) are connected in series with a switch mechanism (20). The series connected circuit made up of the start capacitor (17), the PTC-thermistor (19) and the switch mechanism (20) is connected in parallel with the run capacitor (14).

Abstract: The invention concerns a cylinder head arrangement for a piston compressor, with a cylinder block, in which a compression chamber is formed, which is delimited on one side by a valve plate that is clamped between the cylinder block and a cylinder head cover. In order to provide a cylinder head arrangement that has a high degree of tightness and can be manufactured in a cost-effective manner, the valve plate (6) has on at least one side at least one bead (40) projecting from the valve plate surface (21) concerned.

Abstract: The invention relates to a rotor for an electric motor, especially an electric line-start motor, comprising spaces (4 to 7) which receive permanent magnets (10 to 13) and extend in an axial direction, and spaces (20 to 25) that accommodate conductor rods and extend in an axial direction. In order for the rotor to run as regularly as possible, the spaces (20 to 25) accommodating the conductor rods are provided with a substantially elongate cross-section in at least one sector of the rotor while being embodied in a curved manner along the longitudinal axis thereof in said sector when viewed from a cross-sectional perspective.

Abstract: The invention concerns a piston compressor with a piston, which is connected with a crank pin of a drive shaft via a connecting rod having a longitudinal channel. It is endeavored to make the manufacturing of a piston compressor cost effective. For this purpose, it is ensured that the shaft of the connecting rod is made as a sheet metal pipe.

Abstract: A method and a control unit for starting a compressor (3) in a refrigeration system (1) further comprising a condenser (2) and an evaporator (4). If an attempt to start-up the compressor (3) is unsuccessful a condenser cooling means, e.g. a fan, is started in order to provide cooling for the condenser (2). Thereby, if the temperature of the condenser is sufficiently high to cause an increased pressure on the condenser side of the compressor (3), cooling is provided for the condenser (2) in order to ensure a reliable start-up of the compressor (3). On the other hand, if the temperature of the condenser (2) is sufficiently low to ensure a reliable start-up of the compressor (3), cooling is not provided, thereby saving power while ensuring reliable start-up of the compressor (3).

Abstract: The invention relates to a cylinder head arrangement for a piston compressor, particularly for a hermetically enclosed refrigerant compressor, with a valve plate, a suction gas channel, a discharge chamber and a retainer element for a discharge valve. It is endeavoured to improve the efficiency of the piston compressor. For this purpose, it is ensured that the suction gas channel and the discharge chamber are arranged on different sides of the retainer element.

Abstract: A method and a control system for starting a motor (19), in particular a motor (19) for driving a compressor. The rotational speed (24) of the motor (19) is measured and compared to a minimum value. In the case that ?motor (24) is smaller than the minimum value after a predefined time interval has lapsed, the motor (19) is stopped, and the maximum current level to be supplied by the power source (18) is changed, preferably increased, before a new attempt to start the motor (19) is initiated. Preferably, the voltage (22) supplied to an electronic unit (21) is also measured, and in the case that it drops below a minimum voltage level, the motor (19) is stopped, and the maximum current level is changed, preferably decreased, before a new start attempt is initiated. It is possible to adjust the supplied current level in such a way that power is conserved while sufficient lubricated of the moving parts of the compressor is ensured.

Abstract: The present invention provides to a rotor having a short circuit ring of an electrically conductive material. The short circuit ring has a curved outer surface whereby the eddy-current braking effect on the rotor caused by the stray field from the stator is reduced. The curved surface leads to an improved efficiency of an associated electrical motor. The invention further provides a motor with such a rotor and to the use of a rotor in an electrical motor.

Abstract: A method and a control unit (4) for controlling a supply of power to an electrical circuit comprising a switch (3). An output voltage of a first power source (5), which is connected to the circuit, is measured and compared to a predefined threshold voltage. If the measured voltage is smaller than the threshold value it is determined that the switch (3) is in a closed state, and if the voltage is larger than the threshold value it is determined that the switch (3) is in an open state. The supply of power is controlled in accordance with the open/closed state of the switch (3). Preferably, the electrical circuit is connected to a second power source (9) when the switch (3) is in a closed state. Power is conserved while it is ensured that sufficient power is available when needed. The invention is very suitable for supplying power to a lamp (1) positioned inside a refrigeration compartment (2), especially when the system is battery powered.

Abstract: A method and a control unit for controlling a power level being drawn from a power source (26). Based on a determined rate of change of a measured voltage (1) an estimated remaining runtime is calculated. The estimated remaining runtime represents a time where specific run criteria will no longer be fulfilled if the present power level is maintained. The estimated remaining runtime is compared to a threshold value, and in case the estimated remaining runtime is shorter than the threshold value, the power drawn from the power source (26) is decreased. Thereby the runtime for the power source (26) is maximised. This is particularly useful if the power source is a limited power source, such as a battery (26), e.g. for running a compressor (27) for a movable refrigeration system (24). The invention is suitable for automotive applications.

Abstract: The invention relates to a rotor for an electric motor, particularly an electric line-start motor, comprising axially accommodating spaces (4 to 6) for conductor rods, and axially extending receiving spaces (10, 11) for permanent magnets (14, 15), which are-designed and located in such a way that they generate a permanent magnet field with a magnet axis (22) and a neutral axis (23). The aim of the invention is to ensure that the rotor runs as regularly as possible during the operation of the electric motor. To this end, the diameter of the rotor along the magnet axis is larger than that along the neutral axis (23).