Section 3 — Operation

Guardian Liquid-cooled 27 kW and 30 kW Generators

3.3MANUAL TRANSFER AND

START-UP

To transfer electrical loads to the Standby (EMER- GENCY) power source side and start the engine man- ually, refer to the Owner’s Manual of the particular transfer switch.

3.4ENGINE GOVERNOR

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 governor 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).

Figure 3.2 — Engine Governor Adjustment

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.

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.

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

 

1

UNUSED

POSITION 1

POSITION 2

3

50/60 HZ

GTS/ATS Select

 

 

 

 

ON = 50 HZ

ON = GTS

2

GTS/ATS

OFF = 60 HZ

OFF = ATS (standard mode)

4

50/60 HZ

 

 

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.

3.7WEEKLY EXERCISE CYCLE

The engine control board will start and run the gen- erator once every seven days for approximately 12 minutes. If utility should fail during this exercise period, the engine control board will transfer the load to the generator output and continue to run until util- ity returns.

On the day, and at the time of day chosen for the gen- erator to exercise, set the weekly exercise cycle as fol- lows:

1.Place the AUTO/OFF/MANUAL switch in the AUTO position.

14 Generac® Power Systems, Inc.

Page 16
Image 16
Generac Power Systems 004988-2 owner manual Manual Transfer START-UP Engine Governor Adjustments, Retransfer and Shutdown