Guardian Technologies 4390 Description And Components, Terminal Strip / Interconnection Terminal

SECTION 4.1

DESCRIPTION AND COMPONENTS

PART 4

3DC CONTROL

GENERAL

This section will familiarize the reader with the various components that make up the DC control system.

Major DC control system components that will be covered include the following:

❏A Terminal Strip / Interconnection Terminal

❏A Transformer (TX)

❏A Circuit Board.

❏An AUTO-OFF-MANUAL Switch.

❏A 15 Amp Fuse.

❏A 5 Amp Fuse.

TERMINAL STRIP / INTERCONNECTION

TERMINAL

The terminals of this terminal strip are connected to identically numbered terminals on a prepackaged transfer switch terminal board. The terminal board connects the transfer switch to the circuit board and transformer.

The terminal board provides the following connection points:

A.Utility 1 and Utility 2

1.Connect to identically marked terminals on a prepackaged transfer switch terminal board.

2.The circuit delivers "Utility" power source voltage to the transformer (TX) located in the control panel assembly.

B.23 and 194

1.Connect to identically numbered terminals on the terminal board of the prepackaged transfer switch.

2.This circuit connects the circuit board to the transfer relay coil in the prepackaged transfer switch.

TRANSFORMER (TX)

The control panel assembly’s transformer is a step- down type. The line-to-line voltage from the Utility 1/Utility 2 terminals is delivered to the transformer’s primary winding. Transformer action then induces a reduced voltage (about 12 to 16 volts) into both secondary transformer windings. Reduced voltage from one secondary winding is delivered to the circuit board as "Utility" source sensing voltage. Reduced voltage from the other secondary winding is delivered to the battery charger for trickle charging.

If the Utility sensing voltage drops below a preset value, circuit board action will initiate automatic generator startup and transfer to the "Standby" source side.

The sensing transformer is shown in Figure 2, both pictorially and schematically.

Figure 2. The Transformer

CIRCUIT BOARD

The circuit board controls all standby electric system operations including (a) engine startup, (b) engine running, (c) automatic transfer, (d) automatic retransfer, and (e) engine shutdown. In addition, the circuit board performs the following functions:

❏Delivers "field boost" current to the generator rotor windings (see "Field Boost Circuit" on Page 2.2-1).

❏Starts and "exercises" the generator once every seven days.

❏Provides automatic engine shutdown in the event of low oil pressure, high oil temperature, or overspeed.

A17-pin and a 5-pin connector are used to interconnect the circuit board with the various circuits of the DC systems. Connector pin numbers, associated wires and circuit functions are listed in the CHART on the next page.

Figure 1. Terminal Board

Page 4.1-1