Generac Power Systems 940-2 Rotor Hub, Stator Retaining Ring, Stepper Motor, Stator Assembly

Section 1.2

MAJOR GENERATOR COMPONENTS

ROTOR HUB

See Figure 2 on previous page. The Rotor Hub is bal- anced with the Rotor and must be replaced with the Rotor as an assembly. Part of the engine ignition sys- tem is pressed onto the Hub and can be replaced only as part of the Rotor and Hub assembly.

STATOR RETAINING RING

The Stator Retaining Ring is made of die-cast alu- minum. Four hex head capscrews with lockwashers pass through holes in the Retaining Ring, to retain the Stator Assembly to the Stator Adapter (Item 7, Figure 1).

STEPPER MOTOR

The Stepper Motor (Figure 3) consists of a stepper motor along with a gear and cam arrangement which allows motor movement to change the engine carbu- retor throttle setting. The Motor is controlled by output signals from the Computer Control Circuit Board, which calculates the number of steps the stepper needs to take and generates the required signals to the Motor. The circuit board signals the Motor to actu- ate in response to changes in AC output voltage. Thus, in response to decreasing AC output voltages, the Motor will increase the throttle setting and engine speed will increase. Conversely, Increasing AC out- put voltages will cause the Motor to decrease throttle setting and engine speed will decrease.

STATOR ASSEMBLY

The 2-phase Stator is made up of six (6) windings, with leads brought out as shown in figure 4. Figure 5 is a schematic representation of each stator winding. Note that there are two (2) power phase windings (Leads AC1, AC2, SL1 and SL2 ); a timing winding (Leads TIM1 and TIM2); a power supply winding (Leads PSI, PS2); and a dual battery charge winding (Leads 55, 66, 77).

STATOR ADAPTER

The Adapter is retained to the engine by means of four hex head capscrews. The Stator is retained to the Stator Adapter and is "sandwiched" between the Adapter and the Stator Retaining Ring.

LOWER FAN & FLYWHEEL

The Lower Fan and Flywheel are retained to the engine PTO shaft by means of a conical washer and an M16-1.50 hex nut. When assembling, tighten the flywheel nut to 75 foot-pounds.

Figure 3. The Stepper Motor

ENGINE

The engine is a single cylinder, 220 cc, overhead valve type manufactured by Generac® Power Systems, Inc.

Figure 4. Stator Pictorial View

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