XQC1600 Power Module Caterpillar

Cat Digital Voltage Regulator (Cat DVR)

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The Cat Digital Voltage Regulator presents an electrical shock/electrocution hazard. This hazard will cause serious injury or death. Service by trained personnel only. The terminals and heat sinks are live at hazardous voltages when power is applied and for up to 8 minutes after power is removed.

Illustration 1	g01115009

The Cat DVR is a microprocessor-based voltage regulator. Control power for the Cat DVR is supplied from an external source of 24 VDC. The power stage of the Cat DVR is supplied from a multiple pole high frequency permanent magnet generator. The multiple pole high frequency permanent magnet generator is mounted on the end of the generator shaft. Connections to the Cat DVR are made through three connectors. The communication between the Cat DVR and the service tool is accomplished by using a CANBUS protocol.

The Cat DVR has the following features:

• Three control modes:

1. Automatic voltage regulation (AVR)

2. Power factor (PF) regulation

3. Reactive power (VAR) regulation

• Programmable stability settings

• Soft start control with an adjustable time setting in AVR mode

• Dual slope voltage versus frequency (V/Hz) characteristic

• Three-phase or single-phase voltage sensing

• Single-phase current sensing

• Field current sensing and field voltage sensing

• Ten protection functions

Adjusting the Cat DVR

In order to view and configure the parameters of the Cat DVR, a PC with the Cat DVR software is required.

Refer to Specifications, Systems Operation, Testing and Adjusting, RENR7941, "Cat Digital Voltage Regulator" for complete information.

Integrated Voltage Regulator (IVR)

The Integrated Voltage Regulator (IVR) provides excitation current to the generator. The IVR is controlled by the IVR function in the EMCP4. The IVR function allows the EMCP4 to control the generator voltage, optimize transient performance, and provide feature specification.

The excitation module may interface with any of the following excitation systems: Self Excitation (SE), Internal Excitation (IE) and Permanent Magnet (PMG) excitation systems.

For additional information about the IVR, see Application and Installation, LEBE0006, and Special Instruction, REHS9106.

Illustration 2	g03712568
Excitation Module 10 (EM10) (1) Connector P3 (2) Connector P2 (3) Connector P4

EMCP IVR Connection

To regulate the generator terminal voltage, the EMCP communicates the desired excitation command to the excitation module through a pulse width modulation (PWM) signal. A twisted pair of shielded cable must be used for the communication link. Table 1 details the connections to be made between the EMCP and Excitation Module.

Table 2 provides information on the technical specification of the EM10 and EM15 modules. Selection of the appropriate module must be determined by the following:

• Nominal and maximum generator excitation current at full load (standby 0.8 PF).

• The maximum AC voltage input.

IVR Excitation Module Connections

The EM10 and EM15 excitation modules have three plug type multiple-pin connectors. The connectors are labeled P2, P3, and P4 as shown in illustration 2. Table 3 describes the signal and function of each connector pin.

Note: The X2 and Z1 connections are internally linked within the excitation module. The link provides a point of common connection for the auxiliary windings where an AREP or IE excitation supply is available. Also, the X2 and Z1 connections may be linked externally to the excitation module. Only three connections (X1, X2, and Z2) are needed for the EM. Refer to Systems Operation/Test and Adjust/Troubleshooting, UENR1209, "Integrated Voltage Regulator Connections" for excitation module wiring connections. The wiring diagrams are for self-excitation (shunt), auxiliary windings (AREP/IE), and permanent magnet (PM) configurations.

The voltage regulator knee frequency must be configured for your specific package requirements. The knee frequency for 50 Hz operation will usually be between 48.0 and 49.8 Hz. For 60 Hz operation, the parameter must be set between 58.0 to 59.8 Hz.

Refer to Illustration 3 for an example under-frequency roll-off (loading) profile.

Illustration 3	g03487998
Under-frequency (loading) profile slope1 = 1.0 V/Hz, slope2 = 2.0 V/Hz

EM 15 Excitation Module

Illustration 4	g03727475
Excitation Module 15 (EM15)

The EM 15 excitation module provides excitation current to the generator, and is controlled by the IVR function in the EMCP 4 controls.

Over-excitation Protection

Illustration 5	g03457278

• If a short-circuit fault occurs at the generator terminals, the EM 15 will allow the excitation current to rise to the upper limit value set by the adjustment potentiometer (maximum 15 Amps).

• The excitation current will be clamped at the upper limit value for 10 seconds (fixed internally).

• After 10 seconds, the excitation current is reduced to a value of 10% of the potentiometer setting.

Note: No adjustments should be made directly on the EM 15. All parameters are software configured in the EMCP controller.