REFLECTOR 3762101 - Caterpillar

Lead Numbering
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.The leads are numbered clockwise from the top and from the outside inward. The diagrams that are contained in the "Wye Configuration Diagrams" section show lead numbering for the six lead generators and for the twelve lead generators. The diagrams contained in the "Delta Configuration Diagrams" section show lead numbering for the six lead generators and for the twelve lead generators.Wye Configuration Diagrams
6 Lead
Illustration 1 g00611486
6 Lead Wye Configuration
Terminals T4, T5 and T6 become a neutral connection when the terminals are tied together.
12 Lead
Illustration 2 g00661863
12 Lead Wye Configuration - High Voltage
Terminals T10, T11 and T12 become neutral connection when the terminals are tied together.
Illustration 3 g00611608
12 Lead Wye Configuration - Low Voltage
Terminals T10, T11 and T12 become neutral connection when the terminals are tied together.
Delta Configuration Diagrams
6 Lead
Illustration 4 g00669319
6 Lead Delta Configuration
12 Lead
Illustration 5 g00669312
12 Lead Delta Configuration
Terminals T6 and T9 become the neutral connection when the terminals are tied together and grounded. This reflects the terminal T2 and T10 connection as the high phase.
Grounding the Frame
In any generator set installation, the frame of the generator must be positively connected to an earth ground or to the hull of a vessel. This connection is the first connection that is made at the installation. This connection is the last connection that should be removed. If the generator set is on flexible pads or on resilient pads, the ground connection must be flexible in order to avoid possible breakage in later operation.Ground connection cable or ground connection straps should have at least the current carrying capacity of the largest line lead to the connected load. Joints in cables or in straps must be clean, free of electrical resistance, and protected from possible oxidation. Bolted ground connection joints eventually oxidize. The joints are frequent sources of radio frequency interference (RFI). Silver soldered joints and bolted joints are electrically and mechanically sound.Neutral Connections
The generators with Wye Configuration usually have the neutral ground when the generator is installed. However, there are some cases when definite measures should be taken in order to prevent grounds on the load side. The purpose of the grounding of the neutral is to prevent load side equipment damage.If the neutral wire is grounded and one of the phase leads becomes grounded, the excessive current will open a load circuit breaker. The excessive current will also collapse the generator voltage. The result depends on the following items: particular generator electrical characteristics, type of fault and trip rating of the circuit breaker. An undervoltage device may be required in order to provide an adequate short circuit protection.There are some instances in which it is undesirable to ground the neutral wire. In other applications, it is acceptable to have an ungrounded generator neutral lead. Definite measures should be taken in such applications in order to prevent grounds to the phase leads. An example of such measures are ground