FLO-TECH SPEED CONTROL ELECTRONIC SPEED CON Caterpillar

Introduction

This manual is designed to provide the installer and operator of the Woodward Governor Company Flo-Tech^TM Speed Control the information needed to successfully install the speed control and to provide for operation, maintenance, and troubleshooting of the system.

Declaration of Incorporation

In accordance with the EMC Directive 89/336/EEC and its amendments, this controlling device, manufactured by the Woodward Governor Company, is applied solely as a component to be incorporated into an engine prime mover system. Woodward Governor declares that this controlling device complies with the requirements of EN50081-2 and EN50082-2 when put into service per the installation and operating instructions outlined in the product manual.

Description

The Flo-Tech Speed Control is designed to provide basic isochronous speed control for gas engines using the Flo-Tech Throttle. Engines with mechanical loads and generator loads are handled equally well. Current and potential transformers and a Generator Load Sensor are required to control generator sets which will be paralleled.

Electronic Control

The Flo-Tech Speed Control is housed in a rugged aluminum casting which permits installation on the engine switch gear or generator panel. The electronics are not designed for installation directly on the engine.

The control is available for 12 or 24 Vdc power.

Idle and rated speed references may be set in the control. Rated speed is set with an internal 25-turn potentiometer between 3000 and 6000 Hz. Other ranges are available. (Hz is defined as the number of gear teeth the magnetic pickup will see during one complete revolution of the engine multiplied by the desired rpm divided by 60.)

Isochronous Speed Control

Isochronous control provided by the Flo-Tech Speed Control is always constant within the ability of the engine to carry the load. Multiple engine-generator systems supplying an isolated bus require a load sensor on each generator to provide isochronous load sharing throughout the system. Likewise, load sensors must be used if Flo-Tech-controlled engines are to be connected with a utility bus.

Start Fuel Limit

The adjustable start-fuel limit (cranking throttle) is set with a potentiometer on the control. The limit is automatically enabled whenever the engine shuts down. The limit is disabled when the engine reaches idle or rated speed as selected. If the start-fuel limit feature is not needed, the limit must be set fully clockwise so the fuel control output can go to maximum during start up. Start fuel limit can be adjusted to improve starting, decrease overfueling, and shorten cranking time.

Idle and Rated Speed and Dual Dynamics

Separate dynamics are available for idle and rated speeds as set in the electronic control. Idle speed is set with a separate potentiometer as a percentage of rated speed. The idle speed adjustment can be set between 25% and 100% of rated.

An external switch selects idle or rated dynamics. The switch may be arranged to be operated manually or through a generator breaker auxiliary contact. The idle dynamics are adjusted for the engine characteristic at idle speed unloaded. Rated dynamics are adjusted for the engine characteristics at rated speed or loaded. A common type of installation has the switch close when the engine-generator set is placed on line with a generator breaker closure. Rated dynamics are often set for best response when the engine is loaded. Idle dynamics are always set for best response when the engine is unloaded.

Providing different dynamics at the two selected speeds offers faster response at rated for better engine performance and smooth operating at idle for maximum efficiency and minimum fuel system wear.

Accessories

This manual contains some information about accessories often used with the Flo-Tech Speed Control.

DSLC® Digital Synchronizer and Load Control

The DSLC® control, when connected to each Flo-Tech Speed Control, provides an integrated means to automatically synchronize, control power and power factor, share load, and monitor multi-generator-set systems.

Generator Load Sensor

The Generator Load Sensor provides isochronous load sharing between engines in a multi-generator system by comparing the power output of the generator PT and CTs for each of the three phases from each system generator, and biasing the load sharing line network between the various Flo-Tech controlled engines to compensate for differences in load. The Load Sensor also provides a method to attach an SPM-A Synchronizer and other specialized control items to the generator control system. Generator droop operation can be achieved for infinite bus parallel operation and base loading.

SPM-A Synchronizer

The SPM-A Synchronizer, attached to the Flo-Tech system through a load sensor, will automatically bias the rated-speed setting until an engine/generator is in parallel with the bus. When the speed and generator phases are synchronized with the bus, the synchronizer will call for a breaker closure, smoothly and automatically connecting the generator with the bus.

Acceleration/Deceleration Ramp Generators

A Ramp Generator, or an external capacitor, can be used to increase the time to go from idle to rated speed and from rated speed to idle.

The 8271-909 Ramp Generator provides a linear ramp with times adjustable to 25 seconds in a typical case. Using a capacitor provides about one second of ramp time per 50 ?F, 200 ?F maximum.

References

Publications may be ordered from any Woodward office listed on the back cover of this manual. Woodward Governor Company application engineers are also available to help you in the selection of the correct control for your system, or to answer questions concerning control installation, operation, or calibration. Contact any Woodward office listed on the back cover of this manual.

Figure 1 - 1. Flo-Tech Speed Control and Throttle Applied to a Gas Engine

Figure 1 - 2. Flo-Tech Control Outline Drawing

Figure 1 - 3. Plant Wiring Diagram