| 摘要 |
A method and device for the control of the condition of electrical contacts, in electrical installations (3), particularlyin installations where the contacts and the main current path is encapsulated or in other ways difficult to access. Electrical current is supplied from a current supply (1) which is connected to the main current path of the electrical installation, the progression of the applied current is measured, and the progression of the resulting electrical voltage which appears over a part of the main current path is measured (2), and the resistance over said part is calculated on the basis of the measurements of current and voltage as an expression of the condition of the contacts. The electrical current is discharged from capacitors being a part of the current supply (1), such that at least one unipolar current pulse is formed and approximately corresponding values of the progression of current and voltage are sampled at least in the area near the top of the progression of the current in order to form time series or sequences of samples, i(n) and u(n), respectively. The samples are transferred to a microprocessor or computer (50) for the calculation of the resistance.
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