Guardian Technologies 4759 Description & Components, Stator Assembly, Brush Holder And Brushes

AC GENERATORS

PART 2

SECTION 2.1

DESCRIPTION & COMPONENTS

Wire 4 connects to the positive (+) brush and Wire 0 to the negative (-) brush. Wire 0 connects to frame ground. Rectified and regulated excitation current, as well as current from a field boost circuit, are delivered to the rotor windings via Wire 4, and the positive (+) brush and slip ring. The excitation and field boost current passes through the windings and to frame ground via the negative (-) slip ring and brush, and Wire 0. This current flow creates a magnetic field around the rotor having a flux concentration that is proportional to the amount of current flow.

Figure 2. The 2-Pole Rotor Assembly

STATOR ASSEMBLY

The stator can houses and retains (a) dual AC power windings, (b) excitation winding, (c) battery charge winding and (d) engine run winding. A total of twelve

(12)stator leads are brought out of the stator can as shown in Figure 3.

The stator can is sandwiched between an engine adapter and a rear bearing carrier. It is retained in that position by four stator studs.

Figure 4. Brush Holder and Brushes

Figure 3 Stator Assembly Leads

BRUSH HOLDER AND BRUSHES

The brush holder is retained to the rear bearing carrier by means of two #10-32 x 9/16 Taptite screws. A positive (+) and a negative (-) brush are retained in the brush holder, with the positive (+) brush riding on the slip ring nearest the rotor bearing.

OTHER AC GENERATOR COMPONENTS

Some AC generator components are housed in the generator control panel enclosure, and are not shown in Figure 1. These are (a) an excitation circuit breaker,

(b)a voltage regulator, and (c) a main line circuit breaker.

EXCITATION CIRCUIT BREAKER:

The excitation circuit breaker (CB2) is housed in the generator panel enclosure and electrically connected in series with the excitation (DPE) winding output to the voltage regulator. The breaker is self-resetting, i.e.; its contacts will close again when excitation current drops to a safe value.

If the circuit breaker has failed open, excitation current flow to the voltage regulator and, subsequently, to the rotor windings will be lost. Without excitation current flow, AC voltage induced into the stator AC power windings will drop to a value that is commensurate with the rotor residual magnetism (see Figure 5).

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