Question 128Electricity/Electronics - 1st Asst/Chief70% to pass
As shown in the illustrated diagnostic setup for locating an open field coil of a ten- pole synchronous motor, if 240 VDC is applied across the brushes, what statement is true if one of the field coils is open-circuited? Illustration EL-0203
AI Explanation
The correct answer is C) The voltage across the collector ring and any point before the open will be zero voltage and the voltage across the collector ring and any point after the open will be line voltage.
This is correct because in a synchronous motor with an open-circuited field coil, the voltage across the collector ring and any point before the open will be zero, as the field current cannot flow through the open circuit. However, the voltage across the collector ring and any point after the open will be the full line voltage (240 VDC in this case) since the rest of the field coils are still energized.
The other options are incorrect because they do not accurately describe the voltage behavior across the collector ring and points before and after the open field coil.
Related Questions
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