Generac Power Systems Engine Protective Devices, Main Circuit Breaker, Generator Fuel System

Section 1 - General Information

Guardian Liquid-cooled 10 kW, 15 kW, 20 kW and 25 kW Generators

Figure 3 represents a single-phase, 3-wire generator AC connection system. The stator assembly in this system consists of a pair of stationary windings, with two leads brought out of each winding. Each single winding can supply 120 volts AC, 60 Hertz. When the two windings are connected in series, a 240 volts, 60 Hertz AC output results. Typically the two “hot” leads in the circuit are Wires No. 11 and 44. The “Neutral” leads are the junc- tion of Wires 22 and 33.

Figure 3 - Generator AC Connection System

ENGINE PROTECTIVE DEVICES

The engine has several safety switches which cause the engine to automatically shut down under the following conditions: low oil pressure, high coolant temperature, engine overspeed, low coolant level or overcrank.

LOW OIL PRESSURE SWITCH:

This switch is normally-closed (N.C.) but is held open by engine oil pressure during engine running. Should operating oil pressure drop below about 8-10 psi (55-68 kPa), the switch contacts close and the engine shuts down automatically (Figure 4).

Figure 4 - Low Oil Pressure Switch

MAIN CIRCUIT BREAKER

The generator’s main circuit breaker is included with the unit as shipped from the factory. The breaker for each unit is described as follows:

MODEL	CIRCUIT BREAKER RATING
004090-2, 004124-1	50 amp BQ2 breaker
004091-2, 004125-1	40 amp BQ3 breaker
004092-2, 004128-1	90 amp BQ2 breaker
004093-2	70 amp BQ3 breaker
004094-2, 004126-1	70 amp BQ2 breaker
004095-2, 004127-1	60 amp BQ3 breaker
004096-2, 004130-1	125 amp BQ2 breaker
004097-2, 004131-1	90 amp BQ3 breaker
004474-0, 004475-0	125 amp BQ2 breaker

HIGH COOLANT TEMPERATURE SWITCH:

Normally open (N.O.) thermostatic switch has sensing tip which is immersed in captive coolant. Should coolant temperature exceed about 230°F (110°C), the switch contacts close, which causes the engine to shut down automatically (Figure 5).

Figure 5 - High Coolant Temperature Switch

GENERATOR FUEL SYSTEM

Your unit has been factory tested and adjusted using a natural gas fuel system. If propane (LP) gas is pre- ferred, contact an authorized service dealer.

WARNING: Gaseous fuels such as natural and LP (propane) gas are highly explosive. Even the slightest spark can ignite such fuels and cause an explosion. No leakage of fuel is permitted. Natural gas, which is lighter than air, tends to collect in high areas. LP gas is heavier than air and tends to settle in low areas.

Generac® Power Systems, Inc. 5