A telemeter with pilot coil transmitter

Abstract

The feature of the current-type telemeter described in this paper is the pilot coil which acts as a detector of load changes.^THE current-type telemeter, in which a small direct current proportional to the quantity being measured is transmitted to distant receivers, was one of the earliest and most reliable forms. It has enjoyed wide acceptance and has survived the test of successful operation. Some of the main ad vantages of the current system are as follows:1. The readings are continuous.2. The receiving instruments are simple, rugged, d-c milliammeters of either the indicating or recording type. Only 2 wires are required between the transmitter and receiver.4. The transmitted current is the same in all parts of the telemeter circuit, obviating errors present in potential schemes which are subject to leakage. Telephone cable circuits are suitable for use as telemeter circuits.The telemeter current causes no interference with other circuits in the cable and the leakage resistance of the cable pair is so high as to have negligible effects on the readings. Totalization of various circuits is accomplished with a highdegree of accuracy by paralleling output currents. ELECTRICAL ENGINEERING ILINE J