1. A 250V single phase watt hour meter has a constant load of 5A passing through it for 8 hours at a power factor of 0.8. If the meter disc makes 2400 revolutions during this period, What is meter constant in revolution per kwh? Calculate the power factor of the load if the number of revolutions made by the meter are 1580 when operating at 250V, 6A for 6 hours.
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2. A dynamometer type wattmeter with its voltage coil connected across the load side of the instrument reads 500 watts. If the load side voltage is 250V, What power is being taken by the load? The voltage coil branch has a resistance of 2500 ohm.
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3. A 230V single phase domestic energy meter has a constant load of 5A passing through it for 10 hours at unity power factor. If the meter disc makes 2300 revolutions during the period, What is the meter constant in revoltions per kWh? Calculate power factor of the load if the number of revolutions made by the meter are 1600, when operating at 230V, 10A for 4 hours
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4. A moving coil instrument has a resistance of 10 ohm and gives full scale deflection when carrying a current of 50mA. show how it can be adopted to measure voltage upto 750V and current upto 1000A.
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5. In a test run of 30 minutes duration with a constant current of 5A,the meter register 525Wh. The supply voltage is 220V. Calclate the error and state whether the meter is running fast or slow.
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6. A moving coil voltmeter reading upto 30 millivolts has a resistance of 2 ohm. How this instrument be adopted to read voltage upto 300 volts.
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7. A dynamometer type wattmeter with its voltage coil connected across the load side of instrument reads 300 watts.If theload voltage be 250V. What Power is being taken by the load. The pressure coil branch has a resistance of 3000 ohms.
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8. The constant of an enrgy meter is1400 revoltions/kWh. On connecting a load of 10 lamps of 100 Watt each and 10 fans of 80W the disc maks 2400 revolutions in one hour. State whether the meter is correct or not. If not find the percentage error
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9. A 0-10 Amp ammeter has guaranteed accuracy of 1% of full scale deflection. the limiting error while reading 2.5A will be
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10. To reduce the loading effect, an instrument must possess
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11. A 100mA meter has accuracy of 20%. Its accuracy while reading the 50mA will be
12. The energy capacity of a storage battery is rated in
13. Torque/weight ratio of an instrument indicates
14. A meter reads 127.50 V and the true value of the voltage is 127.43 V. Calculate the static error
15. A 2V peak to peak symmetrical wave is given to a rectifier type AC voltmeter. The voltmeter will read
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