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    ISOLATED MEASUREMENT CIRCUIT FOR SENSOR RESISTANCE
    1.
    发明公开
    ISOLATED MEASUREMENT CIRCUIT FOR SENSOR RESISTANCE 有权
    隔离测量电路是否传感器电阻

    公开(公告)号：EP1779487A1

    公开(公告)日：2007-05-02

    申请号：EP05751803.7

    申请日：2005-06-08

    申请人： ABB Oy

    发明人： LAAKSO, Kari-Matti ,  BERTS, Andreas

    IPC分类号： H02H1/00 ,  G01K7/22

    CPC分类号： G01K7/25 ,  G01K7/24 ,  H02H7/0852

    摘要： The invention relates to measuring the resistance of a resistive sensor, such as a PTC or NTC temperature sensor used for monitoring the temperature of the windings of an electric motor. The invention is based on an electronic circuit in which conductors from a sensor located in the object to be monitored are connected to an amplifier circuit in a feedback configuration that reduces the DC level supplied to the voltage divider when the sensor resistance increases. The measured signal is amplified and, using a comparator to compare it with the output voltage of a sawtooth generator, a continuous PWM (Pulse Width Modulation) signal is generated and transmitted in digital format to a SELV electronic circuit, for example through an opto-isolator. The essentially logarithmic signal amplification makes it possible to reliably distinguish between a short circuit in the sensor circuit and low values of sensor resistance.

    EARTHING AND OVERVOLTAGE PROTECTION ARRANGEMENT
    2.
    发明公开
    EARTHING AND OVERVOLTAGE PROTECTION ARRANGEMENT 审中-公开
    接地和过电压保护装置

    公开(公告)号：EP1766748A1

    公开(公告)日：2007-03-28

    申请号：EP05739498.3

    申请日：2005-05-17

    申请人： ABB Oy

    发明人： LAAKSO, Kari-Matti ,  BERTS, Andreas ,  KUIVALAINEN, Janne

    IPC分类号： H02H9/04

    CPC分类号： G01R1/36 ,  H02H9/04

    摘要： The invention relates to the earthing of an electronic circuit in a device belonging to a low-voltage system with a maximum AC voltage of 1000 V or a maximum DC voltage of 1500 V in which the device is at the main voltage potential or is connected to the main voltage through a high-impedance coupling, as well as to the overvoltage protection of the interface between such an electronic circuit and a SELV (Safety Extra Low Voltage) circuit. The neutral point (COM) of the electronic device is coupled to protective earth (PE) through at least one breakdown-based overvoltage protector. The rated breakdown voltage (Ub) of the overvoltage protector is higher than the voltage present across it in normal operating conditions but lower than the minimum dielectric strength (Uc) of the component forming the interface between the electronic device and the SELV circuit.

    摘要翻译： 本发明涉及属于低压系统的装置中的电子电路的接地，该装置具有1000V的最大AC电压或1500V的最大DC电压，其中该装置处于主电压电位或连接到 通过高阻抗耦合的主电压，以及这种电子电路和SELV（安全超低电压）电路之间的接口的过压保护。 电子设备的中性点（COM）通过至少一个基于击穿的过电压保护器耦合到保护性接地（PE）。 在正常工作条件下，过电压保护器的额定击穿电压（Ub）高于其上的电压，但低于形成电子器件和SELV电路之间接口的组件的最小介电强度（Uc）。