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The current and potential coil of a dynamometer type wattmeter were accidentally interchanged while connecting. After energizing the circuit, it was observed that the wattmeter did not show the reading. This could be due to the 

The current and potential coil of a dynamometer type wattmeter were accidentally interchanged while connecting. After energizing the circuit, it was observed that the wattmeter did not show the reading. This could be due to the  Correct Answer Damage to current coil

Electrodynamometer instrument has two fixed coils and one moving coil. For using this instrument as a wattmeter to measure the power, the fixed coils acts as a current coil and must be connected in series with a load. The moving coil acts as a pressure coil and must be connected across the supply terminals.

In the question given that, the current and potential coils of a dynamometer type wattmeter were accidentally interchanged while connecting. Hence total voltage applies across current coil which has very less resistance which leads to damage the current coil.

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The current and potential coils of a dynamometer type wattmeter were accidentally interchanged while connecting. After energizing the circuit, it was observed that the wattmeter did not show the reading, this could be due to:
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