| 摘要 |
PURPOSE:To induce a prescribed voltage without making winding nor air insulation excessive by grounding the neutral point of one star-connected winding, and opening one terminal of the other triangularly connected winding and making an open type triangular connection. CONSTITUTION:Respective phase windings 8, 8a, and 8a of one high-voltage winding H are star-connected and provided with terminals 1-3 respectively, and their neutral point 4 is grounded through an earth wire 10. Respective windings 9, 9a, and 9a of the other low-voltage winding L are connected triangularly and one terminal 6 is grounded through an earth wire 10 to form an open type. Then a test voltage is so applied from a power source 11 that the prescribed voltage is induced at the terminal 1 of the winding H. At this time, the winding 9a is short-circuited, so both terminals of each phase are at the same potential and a voltage is induced across neither of the windings 8a and 8b of the winding H. Consequently, the voltage between the terminal 1 of the winding H and the ground becomes equal to the voltage between terminals 1-2 and 1-3. Therefore, the insulation of each winding need not be reinforced for the test.
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