APPLICATION AND INSTALLATION GUIDE GOVERNORS – GAS & DIESEL Contents Governors – Gas & Diesel ............................................................... 1 Governor Basics ............................................................................ 2 Droop.................................................................................... 2 Isochronous .......................................................................... 2 Compensation ...................................................................... 3 Speed Band.......................................................................... 3 Transient Response ............................................................. 3 Types of Governors ....................................................................... 4 Hydra-mechanical Governor................................................. 4 Vernier and Positive Lock Governor Control ........................ 4 Governor Control Motor........................................................ 4 Woodward PSG Governor.................................................... 4 Woodward 3161 Governor ................................................... 4 Caterpillar Programmable Electronic Engine Control (PEEC) ................................................................................. 5 Woodward Flo-Tech 68 Governing System.......................... 5 Woodward 8290/524 and 8290/1724 Governors.................. 5 Woodward 2301A Speed Control Governor ......................... 6 Woodward 2301A Load Sharing Governor........................... 6 Woodward 701A and 723PLUS Digital Speed Control......... 8 Woodward ProAct................................................................. 9 Heinzmann E30 Electronic Governor ................................. 10 Generator Set Stability and Response ............................... 10 Governor Selection ...................................................................... 12 Wiring Methods and Considerations............................................ 14 Wire Size and Shielding .......................................................... 14 Wire Size ............................................................................ 14 Shielding............................................................................. 14 Wire Insulation ........................................................................ 14 Connectors.............................................................................. 14 Routing, Support & Protection of Harnesses........................... 14 Routing ............................................................................... 14 Conduit ............................................................................... 14 Support ............................................................................... 15 Separating AC & DC Circuits .................................................. 15 Grounding ............................................................................... 15 Noise & Electromagnetic Interference..................................... 15 Reference Material ...................................................................... 16 Media List................................................................................ 16 Foreword This section of the Application and Installation Guide generally describes Governors for Caterpillar® gas and diesel engines listed on the cover of this section. Additional engine systems, components and dynamics are addressed in other sections of this Application and Installation Guide. Engine-specific information and data is available from a variety of sources. Refer to the Introduction section of this guide for additional references. Systems and components described in this guide may not be available or applicable for every engine. Information contained in this publication may be considered confidential. Discretion is recommended when distributing. Materials and specifications are subject to change without notice. CAT, CATERPILLAR, their respective logos, “Caterpillar Yellow” and the POWER EDGE trade dress, as well as corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission. ©2008 Caterpillar® All rights reserved. Application and Installation Guide Governors – Gas & Diesel Governors – Gas & Diesel While many Caterpillar engines utilize advanced electronic control systems, with integrated engine speed governing capabilities, there are many Caterpillar engines, both gas and diesel, that require the use of separate engine speed governing systems. This section of the Application and Installation Guide discusses governor basics, various governor types and governor features. Engine speed governing systems associated with the advanced electronic control systems are addressed in the Diesel Engine Control Systems and Gas Engine Control and Ignition Systems sections of the Application & Installation Guide. SECTION CONTENTS Governor Basics..................... 2 • Wire Insulation • Connectors Types of Governors................ 4 • Routing & Support Governor Selection .............. 12 • Grounding • Noise & Electromagnetic Wiring Methods and Interference Considerations ..................... 15 • Wire Size & Shielding Reference Material................17 ©2008 Caterpillar® All rights reserved. Page 1 Governors – Gas & Diesel Application and Installation Guide Governor Basics The engine governor in its simplest form controls engine speed. To select the correct governor for a particular application, governor capabilities must be understood. The following terms are commonly encountered when describing governors. Droop Droop describes the relationship of engine speed change from no load (high idle) to full load (rated) in steady state operation. It is the rpm loss experienced when a load is applied to an engine operating at a fixed throttle position. Expressed as a percentage, droop is calculated as follows. (No-load speed – Full-load speed) x % Droop = 100 Full-load speed Figure 1 Figure 1 and Figure 2 describe various degrees of droop for both generator and industrial applications. The percent droop remains constant Industrial Applications and independent of operator speed change. Percent droop will not change if the operator moves the throttle position because the change affects the full load speed. Although the full- load rpm will change, the relationship (% droop) between full-load and no- load will not change. Many applications can easily accept some speed droop. This allows the use of a less costly and less complex Figure 2 governor and still allows, in generator sets, the capability of paralleling with other units. Isochronous Isochronous is a term that describes Generator Applications 0% droop; the engine rpm remains constant as load is applied from no load to full load. This capability is often ©2008 Caterpillar® Page 2 All rights reserved. Application and Installation Guide Governors – Gas & Diesel required on generator sets with certain Figure 3 loads demanding precise frequency control such as communications Transient Response equipment, computers, movie lighting Transient Response is characterized and clocks. Isochronous speed by a speed dip or rise; it is the time capability is also required for interval required for the engine speed automatic paralleling. to recover from a sudden load change. Compensation Dip is the maximum momentary Compensation is a governor decrease in speed (frequency) upon feedback adjustment feature that sudden load increase. allows the governor to be tuned to the Overshoot is the maximum application. Compensation increases momentary increase in speed engine stability. This feature may be (frequency) upon sudden load hydraulic or electrical and increases removal. the cost of the governor. Figure 4 shows an example of how Speed Band an engine reacts to sudden load Speed Band is a tolerance on speed changes. The illustration labels at any steady load. Refer to Figure 3. overshoot at load application, but not For example, the Woodward 3161 at load removal. governor has a speed tolerance of Governors are only one factor ±0.33% while the Woodward 2301A affecting transient response. The size and Heinzmann electronic governors of the engine load, engine offer ±0.25%. configuration, type of generator, voltage regulator and rotating inertia of engine & generator are significant influences on an engine’s recovery capabilities. ©2008 Caterpillar® All rights reserved. Page 3 Governors – Gas & Diesel Application and Installation Guide Figure 4 Types of Governors Application requirements for isochronous operation, depending on governors can range from simple to the application. The industrial engines complex. Just as there are a wide come standard with a positive locking variety of applications, Caterpillar manual speed control. The generator offers a wide variety of governors to sets come standard with a 24 VDC meet customer needs. motor that can provide remote speed adjustment. Even though the PSG has Hydra-mechanical Governor The Caterpillar hydra-mechanical its own oil pump, it uses oil from the governors sense engine speed engine and must use straight weight mechanically, and use the engine’s oil oil for proper governor operation. pressure to hydraulically move the actuator. This governor has a fixed droop, generally 2-15%. Caterpillar hydra-mechanical governors are available for both gas and diesel engine applications. Vernier and Positive Lock Governor Control Vernier and Positive Lock Governor Control is a mechanical device used with the