MEASUREMENT OF RESISTANCE OF WINDING OF TEASER TRANSFORMER OF SCOTT CONNECTION

摘要

PURPOSE:To enable simple measurement with high accuracy, by using a double bridge type DC low resistance measuring instrument and respectively connecting one of two voltage terminals thereof and one of two current terminals thereof to the terminal parts of three-phase windings of a main transformer. CONSTITUTION:The voltage terminal P2 and current terminal C2 of a DC low resistance measuring instrument are connected to the terminal V of a teaser transformer 4 while a voltage terminal P1 and a current terminal C1 are respectively connected to terminals W, U of three- phase winding 2 of a main trans former 1. Then, the resistance of the winding part between the middle point of the three-phase windings 2 of the transformer 1 and the terminal U is set to DELTAX and the resistance of the winding part between the middle point 3 and the terminal V is set to DELTAN. The resistance X of winding to be measured at this time is calculated from a predetermined formula by adding and subtracting resistances N, n so as to bring the current flowing to a galvanometer G to zero. Herein, the resistance DELTAX is regarded as the internal resistance of a battery E and becomes regardless in measurement and the resistance DELTAN can be also disregarded in general because the resistance N is high. When the resistance DELTAN is not disregarded, if resistance DELTAM (wherein DELTAM/DELTAN=M/N) is also added to resistance M and the effect thereof is eliminated, the resistance X of winding can be measured without an error.