CONNECTIONS A typical generator set is outlined in figure 3-8, showing the load cables and output load terminals.

WARNING Before attempting to connect the load cables to the load terminals of a generator set, make sure the set is not operating and there is no input to the load.

Refer to figure 3-8 as you follow this procedural discussion for making load connections. 1. Open the access door and disconnect the transparent cover by loosening six quick-release fasteners. Remove the wrench clipped to the cover. 

NOTE: Be sure to maintain the proper phase relationship between the cable and the load terminals; that is, A0 to L1, B0 to L2, and so forth. 2. Attach the load cables in the following order: L0, L3, L2, and L1 as specified in step 3 below.

Figure 3-8.- Load cable connections.

3. Insert the load cables through the protective sleeve. Attach the cables to their respective load terminals, one cable to each terminal, by inserting the cable in the terminal slot and tightening the terminal nut with the wrench that was clipped to the transparent cover. Install the wrench on the cover and install the cover.

4. Tighten the drawstring on the protective sleeve to prevent the entry of foreign matter through the hole around the cable. You may convert the voltage at the load terminals to 120/ 208 volts or 240/ 416 volts by properly positioning the voltage change board (fig. 3-9). The board is located directly above the load terminal board.

The procedure for positioning the voltage change board for the required output voltage is as follows:

1. Disconnect the transparent cover by loosening the six quick-release fasteners.

2. Remove the 12 nuts from the board. Move the change board up or down to align the change board arrow with the required voltage arrow. Tighten the 12 nuts to secure the board.

3. Position and secure the transparent cover with the six quick-release fasteners and close the access door. 

PHASE SEQUENCE INDICATORS The phase sequence indicator is a device used to compare the phase sequence of three-phase generators or motors. Examples of its use are as follows: to

Figure 3-9.- Voltage change board.

compare the phase rotation of an incoming alternator that is to be operated in parallel with an alternator already on the line or to determine the phase rotation of motors being put into use for the first time. One type of phase sequence indicator is a tiny three-phase induction motor. The three leads of the motor are labeled "A," "B," and "C," as shown in figure 3-10. The insulating hoods over the clips are of different colors: red for A, white for B, and blue for C. The rotor in the instrument can be observed through the three ports as it turns so that you can note the direction in which it rotates. The rotor can be started by means of a momentary contact switch: it, stops again when you release the switch.

You also may use a solid-state phase sequence indicator with two lights. Whichever light is on indicates the phase sequence of the voltage in the conductors that the instrument is connected to; for example, the light labeled "ABC" indicates one phase sequence, while the other light, labeled "BAC," indicates another. If you are working with three-phase conductors (all of the same color) that are installed but not labeled, you may connect the phase sequence indicator to the three conductors, turn on the power, check the phase sequence of the conductors as connected to the instrument, and turn off the power. You may then label the conductors with numbers, letters, or colored marking tape.

You also may check the phase sequence of an incoming alternator before paralleling it with an operating load-side alternator. Connections must be made so that the phase sequence of the two generators will be the same.

Figure 3-11 shows the leads of two generators to be parallel. The proper procedure for ensuring phase sequence with a phase sequence indicator is as follows: Connect indicator terminals A to X1 , B to Yl , and C to Z1 , press the contact switch, and note the direction of rotation of the rotor.

Now move the A terminal to X, the B to Y, and the C to Z, and again press the switch. If the rotor turns in the same direction as before, the phase rotation is the same for the alternators, and the connection can be made X to X1 , Y to Y1 , and Z to Z1 . If the rotor turns in the opposite direction, transpose the connections of any two of the incoming alternator leads before making the connection. It is not absolutely necessary that A be connected to the left-hand terminal, B to the center terminal, and C to the right-hand terminal. This is a practical method, however, used to avoid the danger of confusing the leads. The important thing is to ensure that the phase sequence indicator that was used on X1 be brought down to X, the one used on Y1 to Y, and the one used on Z1 to Z. Reversing any two of the leads will reverse the direction of rotation of the rotor of the instrument.