Generac 004692-0 3.4SEQUENCE OF AUTOMATIC OPERATION, 3.5MANUAL TRANSFER OPERATION, Danger

Models: 004692-0

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3.4SEQUENCE OF AUTOMATIC

Section 3 — Operation

Air-cooled 8.5 kW Generator

3.4SEQUENCE OF AUTOMATIC

OPERATION

The generator’s control panel houses a control logic circuit board. This board constantly monitors utility power source voltage. Should that voltage drop below a preset level, circuit board action will signal the engine to crank and start. After the engine starts, the circuit board signals the transfer switch to activate and connect load circuits to the standby power sup- ply (load terminal lugs T1/T2 connect to terminal lugs E1/E2).

Upon restoration of utility source voltage above a pre- set level, generator circuit board action signals the transfer switch to transfer loads back to that power supply. After retransfer, the engine is signalled to shut down.

The actual sequence of operation is controlled by sensors and timers on a control logic circuit board, as follows:

A.Utility Voltage Dropout Sensor

This sensor monitors utility source voltage.

If utility source voltage drops below about 60 per- cent of the nominal supply voltage, the sensor energizes a 15-second timer.

Once the timer has expired, the engine will crank and start.

B.Engine Warm-up Time Delay

This mechanism lets the engine warm up for about 10 seconds before the load is transferred to a standby source.

C.Standby Voltage Sensor

This sensor monitors generator AC output volt- age. When the voltage has reached 50 percent of the nominal rated voltage, transfer to standby can occur.

D.Utility Voltage Pickup Sensor

This sensor monitors utility power supply volt- age. When that voltage is restored above 80 per- cent of the nominal source voltage, a retransfer time delay starts timing.

E.Retransfer Time Delay

This timer runs for about 15 seconds.

At end of a 15-second delay, circuit board action de-energizes transfer relay in the transfer switch.

Retransfer to utility power source then occurs.

F.Engine Cool-down Timer

When the load is transferred back to utility power source, the engine cool-down timer starts timing.

The timer will run for about one minute, and the generator will then shut down.

3.5MANUAL TRANSFER OPERATION

￿3.5.1 TRANSFER TO GENERATOR POWER SOURCE

To start the generator and activate the transfer switch manually, proceed as follows:

1.Set the generator’s Auto/Off/Manual switch to OFF.

2.Set the generator’s main circuit breaker to its OFF (or open) position.

3.Turn OFF the utility power supply to the transfer switch using the means provided (such as a utility main line circuit breaker).

DANGER

Do not attempt to activate the transfer switch manually until all power voltage supplies to the switch have been positively turned off. Failure to turn off all power voltage supplies may result in extremely hazardous and possibly fatal electrical shock.

4.Use the manual transfer handle inside the trans- fer switch to move the main contacts to their “Standby” position, i.e., loads connected to the standby power source (Figure 3.2).

Figure 3.2 – Manual Transfer Switch Operation

5.To crank and start the engine, set the Auto/Off/Manual switch to MANUAL.

6.Let the engine stabilize and warm up for a few minutes.

7.Set the generator’s main circuit breaker to its ON (or closed) position. The standby power source now powers the loads.

14 Generac® Power Systems, Inc.

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Generac 004692-0 3.4SEQUENCE OF AUTOMATIC OPERATION, 3.5MANUAL TRANSFER OPERATION, 2 – Manual Transfer Switch Operation