Abstract: A method and an arrangement for controlling an inverter provided with a voltage intermediate circuit, the inverter (1) comprising two or more sub-inverters (1A, 1B, 1C), each being connected with a specific cable to feed a common load (2) and each sub-inverter (1A, 1B, 1C) receiving the same switch instruction pattern. The method comprises the steps of determining the magnitude of a time delay, and consecutively generating, with each sub-inverter (1A, 1B, 1C), an output voltage according to the switch instruction for the load (2) such that each sub-inverter generates an output voltage according to the switch instruction after a time equal to the time delay.

Abstract: In a device, such as measuring or control signal transmitter, generating an analog current or voltage output signal, absolute values of output variables are continuously measured and regulated to ensure the correctness of the signal. The actual current or voltage value of an analog output signal is measured and digitized (206), a difference (e) between the digitized actual current or voltage value and the desired current or voltage value is defined (300), and the generation (200, 202, 204, 205) of the analog output signal is controlled (304) by means of a digital control signal (Enable, Direction) so as to decrease the difference.

Abstract: Method and arrangement in connection with a motor fed with a frequency converter provided with an intermediate voltage circuit. The method comprises steps of feeding motor voltage to the motor along a motor cable with a frequency converter for controlling the motor, rectifying the voltage of the motor cable and restricting the magnitude of the voltage of the motor cable at the end of the motor cable on the side of the motor with a clipper circuit coupled in parallel with the motor, using the rectified voltage for rotating one or more cooling fans of the motor.

Abstract: A gate-controlled switch configuration comprising a gate-controlled switch (V4) and a gate driver system (Ctrl, D1, D2, V1, V2), which in its first functional state is configured to change the amount of charge (Qgate) in the gate (G) of the gate-controlled switch (V4) to provide a normal turn-off functionality for the gate-controlled switch (V4), and in its second functional state it is configured to maintain the amount of charge (Qgate) in the gate (G) of the gate-controlled switch (V4) substantially constant. The gate driver system (Ctrl, D1, D2, V1, V2) is configured to produce a soft turn-off functionality during which the gate driver system (Ctrl, D1, D2, V1, V2) is in the first functional state a plural number of times, and between the subsequent first functional states it is in its second functional state.

Abstract: Interface unit for voltage input signals comprising two or more input channels. The input signals of these two or more input channels are connected alternately by an analog multiplexer to an analog-to-digital converter. The A/D converter comprises an integrated sigma-delta modulator circuit which generates a digitized 1-bit signal representing the input signal voltage level for a control unit irrespective of whether the input channel signal is digital or analog. By means of the invention all input voltage channels are made similar such that the input channels of the interface unit can receive an analog or digital signal irrespective of each other.

Abstract: A capacitor charging arrangement to be supplied by a voltage containing network cycles, and having a gate-controlled semiconductor switch (Tch) arranged for charging the capacitor (Caux) and generating a control signal of the gate-controlled semiconductor switch. The control signal is generated with a device that includes a clipper, a first integrator, a second integrator, a cycle indicator, a reset device, an adder, a restricting circuit, a trigger circuit, and an isolation transformer.

Abstract: This invention relates to a lead-through component for a cable. To achieve a lead-through component suitable for cables having a large diameter, the lead-through component includes a shrinkable sleeve that is to be threaded onto a lead-through bushing and whose inner surface is provided with a conductive material layer that comes into contact with the lead-through bushing, the shrinkable sleeve being shrinkable by heating to adhere to the lead-through bushing and to a cable threaded through the lead-through bushing.

Abstract: Interface unit for voltage input signals comprising two or more input channels. The input signals of these two or more input channels are connected alternately by an analog multiplexer to an analog-to-digital converter. The A/D converter comprises an integrated sigma-delta modulator circuit which generates a digitized 1-bit signal representing the input signal voltage level for a control unit irrespective of whether the input channel signal is digital or analog. By means of the invention all input voltage channels are made similar such that the input channels of the interface unit can receive an analog or digital signal irrespective of each other.

Abstract: A method and an arrangement for controlling an inverter provided with a voltage intermediate circuit, the inverter (1) comprising two or more sub-inverters (1A, 1B, 1C), each being connected with a specific cable to feed a common load (2) and each sub-inverter (1A, 1B, 1C) receiving the same switch instruction pattern. The method comprises the steps of determining the magnitude of a time delay, and consecutively generating, with each sub-inverter (1A, 1B, 1C), an output voltage according to the switch instruction for the load (2) such that each sub-inverter generates an output voltage according to the switch instruction after a time equal to the time delay.

Abstract: In a device, such as measuring or control signal transmitter, generating an analog current or voltage output signal, absolute values of output variables are continuously measured and regulated to ensure the correctness of the signal. The actual current or voltage value of an analog output signal is measured and digitized (206), a difference (e) between the digitized actual current or voltage value and the desired current or voltage value is defined (300), and the generation (200, 202, 204, 205) of the analog output signal is controlled (304) by means of a digital control signal (Enable, Direction) so as to decrease the difference.

Abstract: Method and arrangement in connection with a motor fed with a frequency converter provided with an intermediate voltage circuit. The method comprises steps of feeding motor voltage to the motor along a motor cable with a frequency converter for controlling the motor, rectifying the voltage of the motor cable and restricting the magnitude of the voltage of the motor cable at the end of the motor cable on the side of the motor with a clipper circuit coupled in parallel with the motor, using the rectified voltage for rotating one or more cooling fans of the motor.

Abstract: A balancing circuit for voltages of a series connection of capacitors, particularly for intermediate circuit capacitors (3) of an inverter, there being at least two intermediate circuit capacitors connected in series over intermediate circuit voltage. The balancing circuit comprises capacitor-specific freely oscillating inverters (4), the input poles of which are connected in parallel with the capacitor corresponding to the inverter and the output poles of which are connected in parallel to provide a voltage source (Va).

Abstract: A method and arrangement for determining the condition of connectors of an energized device. The method comprises the steps of determining the temperature of connectors carrying a current of a substantially equal magnitude, comparing the differences between the temperatures of the connectors and detecting an increase in the temperature difference between connectors of the device as an indication of a failure in the connection concerned.

Abstract: A gate-controlled switch configuration comprising a gate-controlled switch (V4) and a gate driver system (Ctrl, D1, D2, V1, V2), which in its first functional state is configured to change the amount of charge (Qgate) in the gate (G) of the gate-controlled switch (V4) to provide a normal turn-off functionality for the gate-controlled switch (V4), and in its second functional state it is configured to maintain the amount of charge (Qgate) in the gate (G) of the gate-controlled switch (V4) substantially constant. The gate driver system (Ctrl, D1, D2, V1, V2) is configured to produce a soft turn-off functionality during which the gate driver system (Ctrl, D1, D2, V1, V2) is in the first functional state a plural number of times, and between the subsequent first functional states it is in its second functional state.

Abstract: This invention relates to a lead-through component for a cable. To achieve a lead-through component suitable for cables having a large diameter, the lead-through component comprises a shrinkable sleeve (3) that is to be threaded onto a lead-through bushing (2) and whose inner surface is provided with a conductive material layer (5) that comes into contact with the lead-through bushing (2), the shrinkable sleeve (3) being shrinkable by heating to adhere to the lead-through bushing (2) and to a cable (6, 7) threaded through the lead-through bushing.

Abstract: This publication discloses a phase failure detector (1) for a multi-phase electricity supply network. The phase failure detector includes one detector circuit (3) for each phase (2), which has a first connection point (4) for connecting to the phase (2) being monitored and a second connection point (5), which is connected to a common connection point (9) of the detectors circuits. The detector circuits (3) in turn include capacitive voltage divider elements (6), which are located between the first (4) and the second (5) connection point and with the aid of which reduced voltage is divided and fed to a trigger and detector circuit (8), which is arranged to produce a detection pulse when the reduced voltage reaches a trigger value.

Abstract: An inductor arrangement for a frequency converter or corresponding electrical apparatus, the inductor arrangement comprising an input inductor coupled to the input side of the electrical apparatus and an output inductor coupled to the output side of the apparatus, the input inductor comprising a core element having yokes and columns, and several winding turns for each phase formed around the core element. The output inductor is provided in the inductor arrangement by placing a predetermined length of a conductor of each phase in the output of said electrical apparatus adjacent to the core element of the input inductor.

Abstract: Control circuit for an IGB transistor, which comprises means (T1, V1, C3, C4) for generating auxiliary voltage, a first and a second controllable control switches (V8) connected in series between the auxiliary voltage, and a gate resistor (Rg). The control circuit further comprises a boost capacitor (Cg) connected in series with the gate resistor (Rg), a resistor (R3) whose first terminal is connected to the second terminal (4) of the boost capacitor and whose second terminal is connected to the intermediate voltage level of the auxiliary voltage of the control switches, a Zener diode (V9) whose anode is connected to the point between the gate resistor and the boost capacitor and whose cathode is connected to the point between the boost capacitor and the resistor (R3), and a diode (V10) whose anode is connected to the cathode of the Zener diode (V9) and whose cathode is connected to the positive terminal of the auxiliary voltage of the control switches.

Abstract: A capacitor charging arrangement to be supplied by a voltage containing network cycles, and having a gate-controlled semiconductor switch (Tch) arranged for charging the capacitor (Caux) and generating a control signal of the gate-controlled semiconductor switch. The control signal is generated with a device that includes a clipper, a first integrator, a second integrator, a cycle indicator, a reset device, an adder, a restricting circuit, a trigger circuit, and an isolation transformer.

Abstract: A charging contactor and charging resistor of a capacitor battery in a prior art intermediate circuit of a frequency converter are replaced with three semiconductor switches connected between a three-phase voltage supply and a capacitor battery. When the frequency converter is connected to a supply network, the three semiconductor switches are arranged to operate at first in a current regulating mode in order to charge the capacitor battery using a regulated charging current until the voltage of the capacitor battery reaches a predetermined level. After this, the three semiconductor switches are directed to operate in a diode bridge mode in parallel with an actual network inverter, thus providing a second rectification branch. In a preferred embodiment of the invention, each semiconductor switch comprises a diode and a series connection of a gate-triggered component, preferably a thyristor.