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Problem |
Answer |
1 |
A millivoltmeter with a range of 0 to 50 is to be used with a 400-amp, 50-millivolt shunt. What will be the constant for this combination? |
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2 |
What is the resistance of a 50-millivolt shunt rated at 10 amp? |
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3 |
A direct-reading 5-amp, 100-volt wattmeter is used with a potential transformer of 20:1 ratio and a current transformer of ,50:5 ratio. By what constant must the reading be multiplied? |
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4 |
Give complete instructions for proving the correctness of connections of a polyphase wattmeter, using both current and potential transformers, when measuring a balanced three-phase three-wire load. |
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5 |
A 50-millivolt meter draws 1 milliampere for every 5 millivolts impressed on it. How many ohms in series must be added to cause the meter to read full scale on 150 volts? |
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6 |
A voltmeter with a resistance of 15,000 ohms draws 10 milliamperes with full scale deflection. How could this meter be converted to a satisfactory milliammeter with 10 milliamperes full scale? |
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7 |
It is required to measure a d-c voltage of about 700 volts. A 600-volt meter and a 150-volt meter are available. Is it permissible to use these meters in series and to add their readings? Explain. |
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8 |
In using an ammeter and a wattmeter in the secondary circuit of a current transformer, why must the current coils be connected in series? |
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9 |
In using a voltmeter and a wattmeter in the secondary circuit of a potential transformer, why must the potential coils be connected in parallel? |
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