1-26
Q23. What is the formula used to determine the gain of an amplifying device?
Q24. What are the two inputs to an amplidyne?
SAFETY PRECAUTIONS
You must always observe safety precautions when working around electrical equipment to avoid
injury to personnel and damage to equipment. Electrical equipment frequently has accessories that require
separate sources of power. Lighting fixtures, heaters, externally powered temperature detectors, and alarm
systems are examples of accessories whose terminals must be deenergized. When working on dc
generators, you must check to ensure that all such circuits have been de-energized and tagged before you
attempt any maintenance or repair work. You must also use the greatest care when working on or near the
output terminals of dc generators.
SUMMARY
This chapter introduced you to the basic principles concerning direct current generators. The
different types of dc generators and their characteristics were covered. The following information
provides a summary of the major subjects of the chapter for your review.
MAGNETIC INDUCTION takes place when a conductor is moved in a magnetic field in such a
way that it cuts flux lines, and a voltage (emf) is induced in the conductor.
THE LEFT-HAND RULE FOR GENERATORS states that when the thumb, forefinger, and
middle finger of the left hand are extended at right angles to each other so that the thumb indicates the
direction of movement of the conductor in the magnetic field, and the forefinger points in the direction of
the flux lines (north to south), the middle finger shows the direction of induced emf in the conductor.
