Generac Power Systems 004988-1 owner manual Generator, Transfer Switch, Automatic System Operation

Section 1 - General Information

Guardian Liquid-cooled 27 kW and 30 kW Generators

1.1GENERATOR

This equipment is a liquid-cooled, engine-driven gen- erator set. The generator is designed to supply elec- trical power that operates critical electrical loads during utility power failure. The unit has been facto- ry-installed in a weather resistant, all metal enclosure and is intended for outdoor installation only. Use this generator as a source of electrical power for the oper- ation of 120 and/or 240VAC, single-phase loads.

If this generator is used to power electrical load

!circuits normally powered by a UTILITY power source, it is required by code to install a trans- fer switch. The transfer switch must effectively isolate the electric system from the utility distri- bution system when the generator is operating (NEC 701). Failure to isolate an electrical system by such means results in damage to the genera- tor and may also result in injury or even death to utility power workers due to backfeed of electrical energy.

1.2TRANSFER SWITCH

This generator system may include a matched auto- matic transfer switch which is intended to be used in conjunction with the Generac generator. It is supplied in either a NEMA 1 enclosure or a NEMA 3R enclo- sure. The NEMA 1 enclosure is intended for indoor use only. The NEMA 3R enclosure is weather proof and can be used indoors or outdoors. Follow these rules:

•Install the transfer switch on a firm, sturdy sup- porting structure.

•To prevent switch distortion, level the switch if nec- essary. This can be done by placing washers between the switch enclosure and the mounting surface.

•Never install the switch where water or any corro- sive substance might drip onto the enclosure.

•Protect the switch at all times against excessive moisture, dust, dirt, lint, construction grit and cor- rosive vapors.

If a transfer switch is not included, one may be pur- chased separately from a Generac Authorized Dealer.

1.3AUTOMATIC SYSTEM OPERATION

When this generator, along with a transfer switch, has been installed and interconnected, a circuit board in the generator panel constantly monitors UTILITY power source voltage. Should that voltage drop below a preset value, and remain at such a low state for a preset amount of time, the generator cranks and starts. After the generator starts, the transfer switch transfers load circuits so the generator can power them.

When UTILITY source voltage has been restored, the switch re-transfers back to the UTILITY source volt- age and the generator then shuts down.

Please reference the transfer switch manual for spe- cific information.

1.4GENERATOR AC CONNECTION

SYSTEMS

The generator was shipped from the factory with its stator AC output leads connected in a single-phase, three-wire generator AC connection system (Figure 1.1). 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 120VAC, 60 Hertz. When the two windings are con- nected in series, a 240VAC, 60 Hertz AC output results. Typically the two HOT leads in the circuit are wires 11 and 44. The NEUTRAL leads are the junc- tion of Wires 22 and 33. The NEUTRAL is not grounded.

Figure 1.1 - Generator AC Connection System

			1.5	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 in Figure 1.2.
		Figure 1.2 - Main Circuit Breaker
Model	Rating	Phase	Actual Current	C/B Rating*	Circuit Breaker
004948-0	27,000 NG	1	112.5	150	150A QN2
	30,000 LP	1	125.0	150	150A QN2

* Amp Rating of C/B structured under model.

4 Generac® Power Systems, Inc.