What are the three basic components that instruments used to measure ac voltage, current, watts, and VARs must have?
What will be an ideal response?
1. A spring mechanism to produce an opposing torque; the magnitude of this torque depends on the quantity being measured.
2. A restoring spring mechanism to restore the indicator or pointer of the meter to zero after the required measurement is made. In practice, one mechanism is used to produce the opposing torque and then return the indicator to zero.
3. A damping system to prevent the pointer from overshooting and excessive swinging. If too much damping is provided, a long time is required before the pointer can reach a new reading after a change occurs in the measured quantity. The proper damping means that the pointer moves quickly and stabilizes quickly when the quantity being measured is changed. AC instruments often use electromagnetic damping.
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Which of the following is the symbol for a hydraulic signal?
Figure
When products need to be cooled during flight, ice or ____________________ is used.
Fill in the blank(s) with the appropriate word(s).
Technician A says that wheel cylinder dust boots keep dust and moisture out of the cylinder bore. Technician B says that it is normal for dust boots to allow a little seepage of fluid. Which technician is correct?
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Fill in the blank(s) with the appropriate word(s).