| 摘要 |
<p>The invention relates to a source for the cathodic protection of subterraneous pipelines ensuring a constant pipe-soil potential, adjustable in the range between - 850 and -1,900 mV, independently of the soil physical-chemical parameters variation. The source comprises a rectifier (4), followed by a DC-DC converter furnishing the negative voltage from the output terminal via an output filter (6), the converter comprising width pulse modulation transistors controlled by a control unit (9) comprising a microprocessor, said unit ensuring the voltage adjustment so that, in normal operating duty, the negative voltage be maintained at a pre-established value by means of a program. A second working program can be selected by means of a switch (22), at a constant current, used for testing and calibrating the source functioning.</p> |
