Abstract: The present invention relates to a method for determining the existence of an earth-fault on-the-fly and thereby protecting a motor controller having a high- and a low-side DC-link, and having high- and low-side switching elements, the high- and low-side switching elements being operatively connected to the high- and low-side DC-link buses, respectively, the method comprising the steps of generating a fault signal, generating at least one test vector in response to the fault signal by switching at least one of the switching elements on, and measuring, while the at least one switching element is on, the magnitude of a current flowing in that DC-link operatively connected to the conducting switching element in order to detect an earth-fault. The present invention further relates to additional methods for on-the-fly determination of earth-faults.

Abstract: The invention concerns a method for detecting a fault in a rotating field machine, in which current components are analysed in a flux-based, particularly rotor-flux-based, coordinate system a flux-forming current component being subjected to a frequency analysis in the flux-based, particularly rotor-flux-based, coordinate system. It is endeavoured to provide a simple method for an early detection of faults. For this purpose, a current operating point is detected for at least one predetermined supply frequency (fsp), said operating point being compared to a former operating point.

Abstract: The present invention relates to a method for generating an electric control signal for controlling one or more switching elements of an inverter for driving an electric machine, such as a motor, the method comprising the steps of providing an electric control signal comprising a control frequency and a corresponding control period, dividing a first control period of said electric control signal into a plurality of switching periods, and providing a first switching PWM pulse within a first switching period of a first control period, and providing a second switching PWM pulse within a second switching period of said first control period, wherein the first switching PWM pulse is a minimum-filtered PWM pulse, and wherein the second switching PWM pulse is a corrected PWM pulse. The present invention further relates to an electronic control signal provided according to the before-mentioned method, and to an electronic control system for providing the before-mentioned method.

Abstract: The present invention provides an electronic device, comprising: a circuit board having at least one first heat-generating element and at least one second heat-generating element mounted thereon; a heat sink connected to said at least one first heat-generating element; a fan facing said heat sink; and an airflow guiding member placed between said fan and said heat sink for guiding the cooling air from said fan to said heat sink and said at least one second heat-generating element respectively.

Abstract: A flow distributor assembly (13) for distributing a fluid flow across at least two surfaces (15) to be cooled is disclosed. The flow distributor assembly (13) comprises a first flow distributor (1a) and a second flow distributor (1b). Each flow distributor (1a, 1b) has a set of flow cells (3) formed therein, and comprises a connecting region. The first connecting region and the second connecting region are adapted to interconnect in such a manner that the first flow distributor (1a) and the second flow distributor (1b) are joined to form the flow distributor assembly (13), and in such a manner that the first connecting region and the second connecting region in combination define an inlet manifold (9) and an outlet manifold (10), the inlet manifold (9) and the outlet manifold (10) being fluidly connected to each of the flow cells (3) of the first set of flow cells (3) and the second set of flow cells (3).

Abstract: The present invention provides a pumping system for moving water of a swimming pool, including a water pump and a variable speed motor. In one example, a target volume amount of water and an operational time period is provided, and the operational time period is altered based upon a volume of water moved. In another example, operation of the motor is altered based upon the volume of water moved. In addition or alternatively, a target flow rate of water to be moved by the water pump is determined based upon the target volume amount and a time period. In addition or alternatively, a plurality of operations are performed on the water, and a total volume of water moved by the pump is determined. In addition or alternatively, an optimized flow rate value is determined based upon power consumption.

Abstract: The invention relates to methods for stopping elevators especially when using at least one three-phase motor operated by a static frequency converter. According to the invention, a brake relay controls the brake of the motor such that releasing of the brake relay causes the motor to be decelerated while the brake relay is coupled to a protective circuit in such a way that the control pulses required for generating the driving motor field are safely blocked when the brake relay is released.

Abstract: A pumping system for moving water of a swimming pool includes a water pump and a variable speed motor. The pumping system further includes means for determining a first motor speed of the motor, means for determining first and second performance values of the pumping system, and means for comparing the first and second performance values. The pumping system further includes means for determining an adjustment value based upon the comparison, means for determining a second motor speed based upon the adjustment value, and means for controlling the motor in response to the second motor speed. In one example, the pumping system includes means for determining a value indicative of a flow rate of water moved by the pump. In addition or alternatively, the pumping system includes a filter arrangement. A method of controlling the pumping system for moving the water of the swimming pool is also disclosed.

Abstract: A pumping system includes a pump for moving water. In one aspect, this is in connection with performance of an operation. The system includes a variable speed motor operatively connected to drive the pump. A value indicative of flow rate of water is determined and the motor is controlled to adjust the flow rate indicative value toward a constant. A value indicative of flow pressure is determined and the motor is controlled to adjust the flow pressure indicative value toward a constant. A selection is made between flow rate control and flow pressure control. In another aspect, the pump is controlled to perform a first operation, and is operated to perform a second water operation. Control of operation of the pump to perform the first water operation is altered in response to operation of the pump to perform the second operation.

Abstract: The invention is directed to controlling an electric motor by means of a frequency converter. The frequency converter can be connected to one of several different mains voltages. According to the present invention, the maximum output power of the frequency converter, is limited when the actual mains voltage is lower than the maximum nominal mains voltage, for which the frequency converter is designed, and during the limitation the frequency converter controls the speed of the motor within a power range up to a limited maximum output power. This gives a genuine multi-voltage unit, which can be connected to a wide range of mains voltages.

Abstract: Inrush currents in the dc intermediate circuit of a motor controller necessitate the incorporation of protection circuits. These circuits usually take the form of a resistor inserted in series with the intermediate circuit, and the resistor is short-circuited after completion of inrush by a switch positioned in parallel with the resistor. To reduce cable-transmitted electrical noise an earthed noise-decoupling capacitor is added to the intermediate circuit, but it also requires protection against inrush currents. To minimise the number of components, a protection circuit is described which combines noise filtration and inrush protection.

Abstract: The invention relates to a method for measuring currents in a motor controller. Some current sensing devices placed on the motor wires or inside the motor controller provide low amplitude output signals thus complicating sampling and data processing. In order to improve the signal/noise ratio, an oversampling technique is disclosed which makes used of a differential transmission of the output signal. Further, by applying intelligent sorting techniques on the sampled data, a substantial improvement in the signal/noise ratio can be obtained. The invention also concerns a motor controller using this method, and discloses the use of a power card and a control card, where the current sensing device is placed on the power card and a differential amplifier is placed on the control card. The gain of the differential amplifier is controlled by components placed on the power card as well as on the control card.

Abstract: The invention is directed to controlling an electric motor by means of a frequency converter. The frequency converter can be connected to one of several different mains voltages. According to the present invention, the maximum output power of the frequency converter, is limited when the actual mains voltage is lower than the maximum nominal mains voltage, for which the frequency converter is designed, and during the limitation the frequency converter controls the speed of the motor within a power range up to a limited maximum output power. This gives a genuine multi-voltage unit, which can be connected to a wide range of mains voltages.

Abstract: Method of automated measurement of the ohmic rotor resistance (Rr) of an asynchronous machine (1) controlled via an inverter (8) while being acted upon by a non-rotating field, the method involving a. measuring the ohmic stator resistance (Rs), the leakage inductances (L&sgr;s, L&sgr;r) and the main inductance (Lm) of the asynchronous machine, b. leading a testing signal (Usa) being formed by a predetermined direct signal with a superimposed alternating signal corresponding approximately to the nominal slip frequency (fs) of the asynchronous machine (1), c. measuring the amplitude and the phase (&phgr;) of the phase signal (Isa) resulting from the testing signal, and d. calculating the ohmic rotor resistance (Rr) from the measured values according to a) and c).

Abstract: The invention concerns an electric motor with a stator, in whose bore a rotor is arranged, and with a control arrangement having at least one coil with a core passed by the motor current. The coil shall be arranged in a space saving manner without interfering too much with the magnetic field of the motor. To solve this problem the core of the coil is arranged on the stator whose iron is used for a magnetic circuit.