INSPECTION OF THE GENERATOR  Open all access doors of the generator set and make a thorough visual inspection of the generator for loose or missing mounting hardware and damaged or missing parts (look for broken or loose electrical and hose

Figure 3-11.- Diagram for checking phase sequence of alternators.

connections, for example, and for loose bolts and cap screws). Also, check the fault indicator panel and control cubicle for broken or missing bulbs and fuses.

WARNING While performing your visual inspection, look for service tags. If service tags are present, do not attempt to start or run the generator.

Check the wiring diagrams in the instruction manual furnished with the generator to see whether any wire is connected improperly. If you find faults, correct them immediately. Be sure to check the levels of the following: 1. Crankcase lubricant. 2. Radiator coolant. 3. Fuel. 4. Electrolyte in the batteries. After donning the proper personnel protective equipment (chemical gloves, goggles, and face shield), add to the actual level to bring it up to the required level, if necessary.

On large generators you should check the area ventilation; the fan cover must be opened and latched in that position. There must be no cover or obstructions over the radiator section. The bypass shutters or doors may be closed to shorten the warming-up period, and roof hatches and side louvers may be opened for additional ventilation, if required.

DISTRIBUTION PANELBOARDS  Power from the generator set must be delivered to various connected loads safely and efficiently. The relatively large cables connected to the load terminal board of the generator, if sized properly, can conduct all the power the generator can produce. This power has to get to the different connected load equipment without overloading the conductors or overheating conductor insulations.

In this section, the makeup of panelboards, connections to them, and the installation of the advanced-base type of portable panelboards are presented.

OVERCURRENT PROTECTION If the load cables come into contact with each other and short-circuit the generator, the generator windings could be damaged by excessive current unless the generator windings and load cables are protected by a circuit breaker. The circuit breaker "breaks" or interrupts the circuit anytime there is a short circuit or overload condition in the load cables. One large load, consuming an amount of power at or near the maximum power output of the generator, could theoretically overload the generator in the event of a fault. In this case, one circuit breaker could trip the circuit and protect both the generator and the load. But small-load conductors connected directly to the larger generator load cables could likely burn up without drawing enough current to cause the circuit breaker of the generator set to open the circuit.

In the interest of safe operation of load circuit conductors and safety of area personnel, you must use properly sized overcurrent devices (circuit breakers or fuses). 

DISTRIBUTION The generator load cables are terminated at a type of distribution bus bar from which one or more overcurrent protective devices are connected. Current through each of the overcurrent devices is limited by the overcurrent rating or setting of the device. In this way power from the generator may be safely distributed through protected conductors to the various connected loads.

PANELBOARDS A panelboard includes buses and automatic overcurrent protective devices placed in a cabinet or cutout box and mounted in (flush) or against (surface) a wall or partition. The panelboard is accessible only from the front. A panelboard serves the purpose mentioned above for the distribution of electric power.