Generac Power Systems 004988-4 Manual Transfer And Start-Up, Engine Governor, Adjustments

Section 3 — Operation

Liquid-cooled 30 kW Generators

The system ready LED will be OFF when the switch is in the manual or OFF positions.

Figure 3.2 — Engine Governor Adjustment

The system ready LED is also used to indicate the presence of utility sensing at the PCB when the switch is either in the AUTO or MANUAL modes. The LED will flash at the rate of 1/2 second on, 1/2 second off if the utility sensing level is below the transfer back threshold.

This secondary function is only available with dip switch two in the OFF position (standard ATS appli- cation).

3.3MANUAL TRANSFER AND

START-UP

To transfer electrical loads to the Standby (EMERGENCY) power source side and start the engine manually, refer to the Owner’s Manual of the particular transfer switch.

3.4ENGINE GOVERNOR

LED1

2

U7

C4

C30

R25

R49

U1

.REV E4906 PCB#

DIFFERENTIAL STABILITY

			R44
C9	C27	Q2
				J2
				C26
				D10
				C21
	C2
		RL1		RL2
	R1
	R48
	D17
				J1
	L3
				D19
	DIP SWITCH
4	UNUSED		POSITION 1	POSITION 2
3			50/60 HZ	GTS/ATS Select
2	GTS/ATS		ON = 50 HZ	ON = GTS
			OFF = 60 HZ	OFF = ATS (standard mode)
1	50/60 HZ

ADJUSTMENTS

Engine speed governing is also controlled by the engine control board. Connector J2 on the engine control board interfaces with a governor driver mod- ule and the Bosch throttle body. The engine gover- nor has been set by the factory during final testing of the generator and, in most cases, should not be adjusted.

If, however, adjustments are necessary, or a new engine control board is installed in the generator, the following procedure should be followed (Figure 3.2):

1.Set all three potentiometers (pots) fully counter- clockwise.

2.Under no load condition, increase the GAIN pot as much as possible without causing instability.

3.Apply 1/4, 1/2, 3/4 and full load to the unit. Decrease the GAIN pot if there is instability at any load point.

4.Under full load condition, increase the stability pot until the unit returns to 60 Hertz (or 50 Hertz in 50 Hertz applications).

5.Reduce load to 3/4, 1/2, 1/4 and no load. Decrease the stability pot if there is instability at any load point.

6.Adjust differential pot to make the recovery to load changes even faster and minimize load change undershoot and overshoot. If it is set too high it may introduce oscillations at some load. It can be set to zero (full CCW) if a small amount causes oscillations at some load.

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3.5RETRANSFER AND SHUTDOWN

When utility power source voltage has been restored, electrical loads may be transferred back to that source and the generator can be shut down as fol- lows:

•Verify that UTILITY power supply voltage to the transfer switch has been positively turned OFF, using whatever means provided (such as utility main line circuit breaker).

•Set the generator’s main circuit breaker to its OFF or OPEN position.

•Let the generator engine run at no-load for a few minutes, to stabilize internal unit temperatures.

•On the generator console, set the AUTO/OFF/ MANUAL switch to OFF. Wait for engine to come to a complete stop.

•For transfer to utility position, refer to the Owner’s Manual of the particular transfer switch.

•Turn on the UTILITY power supply to the transfer switch, using whatever means provided (such as a utility main line circuit breaker). The UTILITY power source now powers the loads.

3.6AUTOMATIC OPERATION

To set the system for fully automatic operation, pro- ceed as follows:

•Check that load circuits are connected to the utility power supply.

•Set the AUTO/OFF/MANUAL switch to its AUTO position.

•Set the generator main circuit breaker to its ON or CLOSED position.