STOP 1P8612 - Caterpillar

Cat Digital Voltage Regulator (Cat DVR)
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 g03844029The 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:
Automatic voltage regulation (AVR)
Power factor (PF) regulation
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 functionsAdjusting the Cat DVR
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 g03844853
Excitation Module 10 (EM10)
(1) Connector P3
(2) Connector P2
(3) Connector P4EMCP 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 1
EMCP 4.1 and EMCP 4.2 Connections to Excitation Module (70-pin connector)
EMCP 4.1 and EMCP 4.2 70-Pin Connector Excitation Module 3-Pin Connector
Digital Output #2 / IVR CS+ 68 CS+ P3-2
Battery negative splice 60 or 65 CS- P3-3
Battery negative splice 60 or 65 Shield P3-1
EMCP 4.3 and EMCP 4.4 Connections to Excitation Module (120-pin connector)
EMCP 4.3 and EMCP 4.4 120-Pin Connector Excitation Module 3-Pin Connector
PWM Output #2 Positive 28 CS+ P3-2
PWM Output #2 Negative 8 CS- P3-3
Shield 19 Shield P3-1 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.
Table 2
EM10 and EM15 Technical Specifications
EM10 EM15 EM25
Compatible Generator Excitation Types Permanent Magnet (PM) Self-Excitation (SE) Internal Excitation (IE/AREP)(1)
Nominal Field Current