OPERATOR AR 3757663 - Caterpillar

6 Lead
Illustration 2 g00611486
6 Lead Wye Configuration
Terminals T4, T5 and T6 become neutral connection when the terminals are tied together.
10 Lead
Illustration 3 g00669334
10 Lead Wye Configuration - High Voltage (for 3306B and 3406C generator sets only)
Terminal T0 is the neutral lead.
Illustration 4 g00611596
10 Lead Wye Configuration - Low Voltage (for 3306B and 3406C generator sets only)
Terminal T0 is the neutral lead.
12 Lead
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12 Lead Wye Configuration - High Voltage
Terminals T10, T11 and T12 become neutral connection when the terminals are tied together.
Illustration 6 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 7 g00669319
6 Lead Delta Configuration
12 Lead
Illustration 8 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 one that is made at the installation. This connection is the last one that should be removed. If the generator set is on flexible or resilient 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). Silver soldered 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 which can 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 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. An ungrounded generator neutral lead is acceptable in the applications in which definite measures have been taken in order to prevent grounds to the phase leads. An example of such measures are ground fault protective circuits. Ground fault protection requires that the entire group of distribution circuits should be studied and treated as a system. The owner should engage a certified and registered consultant if a new distribution system is being developed. The owner should also engage a certified and registered consultant if an existing system should be modified for the ground fault protection.