SR4 Generator with VR3 or VR4 Voltage Regulator Caterpillar

The wye configurations and the delta configurations are the most common generator lead connections. The following three-phase connection diagrams illustrate the proper connection and lead identification for Wye configurations and Delta configurations.

Four Lead Wye Connection

Illustration 1	g00611469
Four Lead Wye Connection Diagram

Table 1

FOUR LEAD WYE CONNECTIONS
Generator Lead	Line Lead	Regulator Lead
T1	T1	22
T2	T2	24
T3	T3	20
T0	Neutral	-

Six Lead Wye Connection

Illustration 2	g00611486
Six Lead Wye Connection Diagram

Table 2

SIX LEAD WYE CONNECTIONS
Generator Lead	Line Lead	Regulator Lead (1)
T1	T1	22
T2	T2	24
T3	T3	20
Connect T4, T5, and T6	Neutral	-

( 1 )

Regulator leads are used on Generator sets with a 3500B Engine. On PMPE generators, sensing isolation transformers are used. The line lead's voltage connects to one side of the sensing isolation transformer. The voltage regulator connects to the other side of the sensing isolation transformer. On SE generators, the stator windings are tapped in order to supply sensing voltage to the regulator.

Ten Lead Wye Connection (High Voltage)

Illustration 3	g00611584
Ten Lead Wye Connection Diagram (High Voltage)

Table 3

TEN LEAD WYE CONNECTIONS (HIGH VOLTAGE)
Generator Lead	Line Lead	Regulator Lead
T1	T1	-
Connect T4 and T7	-	22
T2	T2	-
Connect T5 and T8	-	24
T3	T3	-
Connect T6, T9	-	20
T0	Neutral	-

Ten Lead Wye Connection (Low Voltage)

Illustration 4	g00611596
Ten Lead Wye Connection Diagram (Low Voltage)

Table 4

TEN LEAD WYE CONNECTIONS (LOW VOLTAGE)
Generator Lead	Line Lead	Regulator Lead
Connect T1 and T7	T1	22
Connect T2 and T8	T2	24
Connect T3 and T9	T3	20
Connect T4, T5, T6, and T0	Neutral	-

Twelve Lead Wye Connection (High Voltage)

Illustration 5	g01027757

Table 5

TWELVE LEAD WYE CONNECTIONS (HIGH VOLTAGE)
Generator Lead	Line Lead	Regulator Load
T1	T1	-
Connect T4 and T7	-	22
T2	T2	-
Connect T5 and T8	-	24
T3	T3	-
Connect T6 and T9	-	20
Connect T10, T11, and T12	Neutral	-

Twelve Lead Wye Connection (Low Voltage)

Illustration 6	g00611608
Twelve Lead Wye Connection Diagram (Low Voltage)

Table 6

TWELVE LEAD WYE CONNECTIONS (LOW VOLTAGE)
Generator Lead	Line Lead	Regulator Lead
Connect T1 and T7	T1	22
Connect T2 and T8	T2	24
Connect T3 and T9	T3	20
Connect T4, T5, T6, T10, T11, and T12	Neutral	-

Twelve Lead Delta Connection

Illustration 7	g00611504
Twelve Lead Delta Connection Diagram

Table 7

TWELVE LEAD DELTA CONNECTIONS
Generator Lead	Line Lead	Regulator Lead
Connect T1 and T12	T1	22
Connect T4 and T7	-	-
Connect T2 and T10	T2	24
Connect T5 and T8	-	-
Connect T3 and T11	T3	20
Connect T6 and T9	Neutral	-

Note: A Delta connection is only available for twelve lead generators.

Note: A Delta connection may require certain generators to be derated.

Generator line leads (T1 through T12) can be multiple. For example, three generator line leads might be designated as T4. Multiple line leads allow the leads to be flexible. Flexible leads help maintain the current carrying capacity which is required. If generator line leads are similarly marked, these leads should be connected together. These leads should be treated as one conductor. Generator line leads can terminate in the following ways:

• end at the terminal strip

• directly fastened to the load leads

• fastened to another component

For more information, refer to Testing And Adjusting, "Leads - Connect".

Depending on the connections that are made between the load and the generator line leads, single-phase voltages and/or three-phase voltages are possible. For more information, refer to Operation and Maintenance Manual, LEKQ7119, "Engine Data Sheet".