ALTERNATOR GP-CHARGING 3660669 - Caterpillar

Lead Numbering
Illustration 1 g00661863
12 Lead Wye Configuration for High Voltage
Terminals T10, T11, and T12 become a neutral connection when the terminals are tied together.
Illustration 2 g00611608
12 Lead Wye Configuration for Low Voltage
Terminals T4, T5, T6, T10, T11 and T12 become a neutral connection when the terminals are tied together.
Illustration 3 g00669312
12 Lead Delta Configuration
Terminals T6 and T9 become a neutral connection when the terminals are tied together and 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 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 mounting pads, the ground connection must be flexible in order to avoid possible breakage in later operation.Ground connection cable 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. The joints are frequent sources of radio frequency interference (RFI). Joints that are silver soldered and bolted are preferred.Neutral Connections
The generators with a Wye Configuration usually have the neutral ground when the generator is installed. Grounding the neutral is for preventing damage to equipment.If the neutral wire is grounded and one of the phase leads becomes grounded, the excessive current will open a load circuit breaker. Also, the excessive current will cause the generator voltage to collapse. The result depends on the following items: electrical characteristics of the generator, 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 cases when the neutral wire is not grounded. An ungrounded generator neutral lead is acceptable when the possibility of grounds to the phase leads has been eliminated. An example of such measures are ground fault protective circuits. Ground fault protection requires the entire group of distribution circuits to be treated as a system. The owner should contact a certified consultant if a new distribution system is being developed. The owner should also contact a certified consultant if an existing system should be modified for the ground fault protection. Single Units
In a three-phase, four-wire system, the neutral wire should be grounded according to local wiring codes. Be sure to check your local wiring codes.