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Figure 2E.—Megger circuit.
IN ANSWERING QUESTION 2-42, REFER
TO FIGURE 2E.
2-42. In the megger circuit, what component
prevents leakage current from affecting
ohmmeter measurements?
1. Guard ring
2. Generator
3. Resistor R3
4. Coil
2-43. When a megger is used to measure an
unknown resistance, what circuit action
causes the pointer to come to rest at the
correct resistance value?
1. The current flow in coil A
2. The current flow in coil B
3. The interaction between the currents
in coils A and B
4. The interaction between the
restraining springs of the meter and
the current in coil A
2-44. A megger uses high voltage to check the
insulation leakage in the megohm range.
What is the source of this voltage?
1. Batteries
2. The ship's ac power
3. The ship's dc power
4. A hand-driven dc generator
2-45. Meggers with which of the following
maximum voltage ratings are commonly
found in the fleet?
1. 500 volts
2. 700 volts
3. 1,000 volts
4. 2,500 volts
2-46. When a megger is used to measure the
resistance of an electrical cable, what
does a reading of infinity indicate?
1. The meter is faulty
2. The cable is shorted
3. The cable is grounded
4. The resistance is too large to measure
2-47. A megger is prevented from exceeding
its rated output voltage by which of the
following actions?
1. Battery discharge limits the voltage
2. Tension in the cable
3. Friction clutch slippage
4. Current leaks through internal
insulation
2-48. When the crank of a 500-volt megger is
rotated faster than its designed rate, what
maximum output voltage does it
produce?
1. 100 volts
2. 500 volts
3. 520 volts
4. 550 volts
