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2016/03/09 Voltage Regulators (SEBU9034-17)

SMCS - 4467 i06599577

Integrated Voltage Regulator (IVR)

PPI
The Integrated Voltage Regulator (IVR) is a feature within the EMCP 4 that regulates the generator output voltage by signaling a desired
excitation command to the EM10 Excitation Module. The Excitation Module then provides field current to the generator exciter. The IVR function

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allows the EMCP 4 to control the generator voltage, with enhanced transient performance.

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The EM10 Excitation Module may interface with any of the following excitation systems: Self Excitation (SE), Internal Excitation (IE), and

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Permanent Magnet (PMG) excitation systems.

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

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Illustration 1 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 shielded twisted pair of cables must be used for the communication link. Table 1 details the connections to be
made between the EMCP and Excitation Module.

Table 1

EMCP 4.2B Connections to Excitation Module (70-pin connector) 

EMCP 4.2B 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 4.4 Connections to Excitation Module (120-pin connector) 
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 

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Table 2 provides information on the technical specification of the EM10 module. 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 Technical Specifications 

Compatible Generator Excitation Types  Permanent Magnet (PM) Self-Excitation (SE) Internal Excitation (IE/AREP)(1) 
Nominal Field Current Output  6A 
Maximum (forcing) Field Current Output  10A 
Maximum AC Voltage Input  180Vms 
(1)
Internal Excitation (IE is also referred to as “Auxiliary Regulation Excitation Principle”(AREP)

IVR Excitation Module Connections

The EM10 excitation module has three plug type multiple-pin connectors. The connectors are labeled P2, P3, and P4 as shown in illustration 1.
Table 3 describes the signal and function of each connector pin.

Table 3

Excitation Module Connections 

Terminal  Label  Signal/Function 

P2-1  F+  Exciter Field Positive 
P2-2  F-  Exciter Field Negative 
P3-1  Shield  Excitation Command Control Signal Shield 
P3-2  CS+  Excitation Command Control Signal Positive 
P3-3  CS-  Excitation Command Control Signal Negative 
P4-1  X2  Excitation Power Supply Input X2 
P4-2  Z1  Excitation Power Supply Input Z1 
P4-3  X1  Excitation Power Supply Input X1 
P4-4  Z2  Excitation Power Supply Input Z2 

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 2 for an example under-frequency roll-off (loading) profile.

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Illustration 2 g03487998
Under-frequency (loading) profile (In this example slope1 = 1.0 V/Hz, slope2 = 2.0 V/Hz)

Over-Excitation Protection

Illustration 3 g03457278

If a short-circuit fault occurs at the generator terminals, the EM10 will allow the excitation current to rise to the upper limit value set by the
adjustment potentiometer (maximum 10 Amps)

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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

For more information about EM10, contact your Cat dealer.

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2023/02/11
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© 2023 Caterpillar Inc.

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