RIVET-BLIND 1263842 - 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. The diagrams that are contained in the "Wye Configuration Diagrams" section show lead numbering for the six and twelve lead generators. The diagrams that are contained in the "Delta Configuration Diagrams" section show lead numbering for the six and twelve lead generators.Wye Configuration Diagrams
6 Lead
Illustration 1 g00611486
6 Lead Wye Configuration
Terminals T4, T5, and T6 become neutral connections when the terminals are tied together.
12 Lead
Illustration 2 g00661863
12 Lead Wye Configuration
High Voltage
Terminals T10, T11, and T12 become neutral connections when the terminals are tied together.
Illustration 3 g00611608
12 Lead Wye Configuration
Low Voltage
Terminals T10, T11, and T12 become neutral connections 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 connections when the terminals are tied together and when the terminals are 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 the frame of the generator must be positively connected to the hull of a vessel. This connection is the first connection that should be made at the installation. This connection is the last connection that should be removed. If the generator set is on flexible pads or resilient pads, the ground connection must be flexible in order to avoid possible breakage in later operation.Ground connection cables or straps should have at least the current carrying capacity of the largest line lead to the connected load. Joints in cables or straps must be clean, free of electrical resistance, and protected from possible oxidation. Bolted ground connection joints eventually oxidize. These joints are also frequent sources of radio frequency interference (RFI). Joints should be silver soldered and joints should also be bolted. These bolts will be electrically reliable and mechanically reliable.Neutral Connections
On Wye Configuration Generators, the neutral lead should be attached to ground. This connection should be made at installation. The neutral lead is grounded in order 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. In addition, this excessive current will cause the generator voltage to collapse. The result depends on the following factors: the particular electrical characteristics of the generator, type of fault and trip rating of the circuit breaker. An undervoltage device may be required to provide an adequate short circuit protection.There are some instances when the neutral wire should not be grounded. An ungrounded generator neutral lead is acceptable when measures have been taken to prevent grounds to the phase leads. An example of such measures are ground fault protective circuits. When ground fault protective circuits are used, the