Chapter 1. General Information

Description

The 2301A Speed Control controls the speed or load of diesel or gas engines, or steam or gas turbines. These power sources are referred to as "prime movers" throughout this manual.

The control is housed in a sheet-metal chassis and consists of a single circuit board. All potentiometer are accessible from the front of the chassis.

The 2301A Speed Control provides control in the isochronous mode with droop available through and externally wired potentiometer.

The isochronous mode is used for constant speed of the controlled prime mover as long as it is able to provide the load. Isochronous is also used when load sharing with Woodward load sensor.

External droop is used for speed control as a function of load when a prime mover is operating on an infinite bus or when two or more prime movers are in parallel operation.

The 2301A system for a prime mover includes:

* A 2301A electronic speed control,

* An external power source,

* A speed-sensing device (MPU), and

* A proportional actuator to position the fuel- or steam-metering device.

Part Number Table

Applications

2301A Speed Controls are available for forward- or reverse-acting applications for use with single or tandem actuators. High voltage models accept 88 to 132 Vac or 90 to 150 Vdc. Low voltage models accept 10 to 40 Vdc supply.

See the Part Number Table above for a listing of 2301A Speed Controls an applications.

Speed range is set on an internal dip switch, available inside the steel cover of the control. Speeds are set according to the sensor output frequency. The relationship between the prime mover speed and sensor output frequency is expressed in the formula: Sensor Frequency in Hz equals the number of teeth on the speed-sensing gear times the revolutions per minute of the sensing gear, times the ratio of the engine speed to the sensing gear speed, divided by 60.

Reverse Acting

Most reversing 2301A Speed Controls will operate Woodward EGB governor/actuators. In reverse-acting systems, the actuator calls for more fuel when the actuator current decreases. Complete loss of signal to the actuator will drive the actuator to full fuel. This allows a backup mechanical ball head governor to take control rather than shutdown the prime mover as would a direct-acting system.

External wiring connections for reverse-acting controls are identical to those for direct-acting controls. However, changes must be made to the printed circuit board should a control need to operate the opposite type of actuator. Contact Woodward should it be necessary to change the type of 2301A Speed Control. Changing the supply voltage rating requires exchanging the unit for the properly rated control.

References

The following Woodward publications contain additional product or installation information on speed controls and related components. These publications are available on the Woodward website (www.woodward.com).

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 declares that this controlling device complies with the requirements of EN50081-2 and EN50082-2 when put into service per the installation and operating instruction outlined in the product manual.

Chapter 2. Installation

Introduction

This chapter contains general installation instructions for the 2301A Speed Control. Power requirements, environmental precautions, and location considerations are included to determine the best location for the control. Additional information includes unpacking instructions, electrical connections, and an installation check-out procedure.

Unpacking

Before handling the control, read page ii, " Electrostatic Discharge Awareness". Be careful when unpacking the electronic control. Check the control for signs of damage such as bent or dented panels, scratches, and loose or broken parts. Notify the shipper of any damage.

Selection Of Speed Range

a 4-pole mini-switch is located on the lower left-hand quarter of the pointed circuit board. This switch sets the controlling speed range as sensed by the MPU. The speeds are related to the MPU frequency, which is proportional to engine rpm. The control is shipped with Switch 3 on for 2000 to 6000 Hz. Switch 1 provides 500 to 1500 Hz, Switch 2 provides 1000 to 3000 Hz, and switch 4 provides 4000 to 12000 Hz. Select only one switch on to match the control to the MPU frequency.

Figure 2-1. Speed Range Switch

Power Requirements

Power supply output must be low impedance (for example, directly from batteries). DO NOT power low-voltage versions of the control from high-voltage sources with resisters and zener diodes in series with the control power input. The 2301A control contains a switching power supply which requires a current surge to start properly.

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CAUTION-CHECK INPUT VOLTAGE To prevent damage to the control, do not power low-voltage versions of the control from high-voltage sources.

High and low voltage models of 2301A Speed Controls are available. Low voltage models require a supply of 10 to 40 Vdc. High voltage models require a supply of 88 to 120 Vac or 90 to 150 Vdc., 12W. The ac supply may be 50 to 400 Hz.

If a battery is used for operating power, an alternator or other battery charging device is necessary to maintain a stable supply voltage.

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CAUTION-BATTERY To prevent damage to the control, make sure that the alternator or other battery-charging device is not connected to the control when the battery is disconnected from the control.

Location Considerations

Consider these requirements when selecting the mounting location:

* Adequate ventilation for cooling

* Space for servicing and repair

* Protection from direct exposure to water or to a condensation-prone environment

* Protection from high-voltage or high-current devices, or devices which produce electromagnetic interference

* Protection from excessive vibration

* An ambient operating temperature range of -40 to +85°C (-40 to +185°F)

Do not mount the control on the engine.

Electrical Connections

External wiring connections and shielding requirements for a typical control installation are shown in the plant wiring system, diagrams 2-4 and 2-5. These wiring connections and shielding requirements are explained in the balance of this section.

Shielded Wiring

All shielded cable must be twisted conductor pairs. Do not attempt to tin the braided shield. All signal lines should be shielded to prevent picking up stray signals from adjacent equipment. Connect the shields to the grounding lug on the chassis plate below terminal 9. Keep grounding connections under 2 inches (5 cm) length. A solid ground connection must be made from "earth" or ground to the grounding lug to provide proper chassis grounding. Refer to local wiring codes for proper grounding methods.

Wire exposed beyond the shield should be as short as possible, not exceeding 6 inches. The other end of the shields must be left open and insulated from any other conductor. Do not run shielded signal wires with other wires carrying large currents. See Appendix B, EMI Control for electronic Governing Systems, for more information.

Where shielded cable is required, cut the cable to the desired length and prepare the cable as instructed below and shown in Figure 2-2.

Figure 2-2. Preparation of Shielded Cables

1. Strip outer insulation from both ends, exposing the braided or spiral wrapped shield. Do not cut the shield on the control end. Cut off the shield on the end away from the 2301A control.

2. Use a sharp, pointed tool to carefully spread the strands of the shield.

3. Pull the inner conductors out of the shield. Twist braided shields to prevent fraying.

4. Connect lugs to the shield and to the control wires. Number 6 slotted or round crimp-on terminals are used for most installations. Connect the wires to the appropriate terminals on the control and the shield to the grounding lug below terminal 9.

Installations with severe electromagnetic interference (EMI) may require shielded wire run in conduit, double shielded wire, or other precautions. Contact Woodward for additional information.

External Adjustments

Speed Trim

A speed trim potentiometer or digital reference unit is connected to terminals 11 and 12. Use a high quality 100 ohm, 10-turn potentiometer (Woodward part 1657537 or equivalent) to provide about ±5% speed adjustment. Terminals 11 and 12 must be jumpered if the speed trim potentiometer or digital reference unit is not used. The 2301A Speed Control will have a jumper installed in the factory and this must be removed if a speed-trim device is used.

Droop Potentiometer

A 2K potentiometer may be connected to provide a maximum of about 8% droop. Connect the potentiometer (ccw) to terminal 15, (cw) to terminal 14, and wiper to terminal 13. If droop is not desired make no connections to terminals 13 and 14.

Switch Options

Minimal Fuel Contact

The minimum-fuel contact between terminals 2 and 3 on the low-power models and 3 and 6 on the high-powered models is intended as an optional means for a normal shutdown of the prime mover. The contact is connected as shown on the plant wiring diagram for the particular control. If a minimum fuel contact is not used, the terminals must be permanently jumpered.

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WARNING-EMERGENCY STOP Do NOT use the minimum-fuel contact as a part of any emergency stop sequence. The emergency may be caused by a governor malfunction which would also case a malfunction of the minimum-fuel feature. Use of the minimum-fuel contact for an emergency stop sequence could cause overspeed of the prime mover and mechanical damage and personal injury, including death.

Failed Speed Signal Override

Circuits in the 2301A Speed Control constantly monitor the signal from the MPU. Should this signal be below a minimum threshold the control sends a minimum fuel signal to the actuator (maximum fuel signal in a reverse acting control).

Before start-up of the prime mover, the speed signal is nonexistent, activating the failed speed signal circuit. On units with cranking motors, the cranking speed is usually sufficient to provide a speed signal, so an override contact is not needed for starting. On some steam turbine systems, the Close for Override of Failed Speed Signal contact must be closed to allow the actuator to open and provide steam for starting.

The failed speed-signal override switch should be a momentary switch so the failed-speed-sensor circuit will be enabled after start-up.

Idle/Rated Ramp Contact

Connect a single-pole, single throw switch to terminal 5 as shown on the appropriate plant-wiring diagram. Close the contact for rated, open for idle. Oil pressure is often used to close this contact. When closed, 10 to 40 Vdc is applied to terminal 5, and the prime mover can be operated at a speed higher than idle. When the contact is open, the voltage is removed from terminal 5, and the prime movers speed decelerates to idle. The ramp rate applies only to the acceleration mode. When the ramp time potentiometer is full cw the ramp time from idle to rated is 22 ± 4 seconds. When the ramp time potentiometer is fully ccw ( be careful not to overtorque the pot), the ramp rate is less than 1 second from idle to rated.

The ramp time from rated to idle is always less than 1 second, regardless of the setting of the ramp-time potentiometer.

Actuator Output

The actuator wires connect to terminals 9 (+) and 10 (-). Use shielded wires with the shield connected to the grounded post on the panel. Do not connect the shield to the actuator or to any other point. The shield must have continuity the entire distance to the actuator and must be insulated from all other conductors.

Some 2301As may be used to operate prime movers in tandem be wiring the two actuators in series as shown in detail A of the wiring diagram. Tandem operation with a single 2301A control requires that the two engines provide identical power response to identical current signals to each of the actuators.

NOTE: Electromagnetic Interference (EMI) can be an intermittent condition. Improperly shielded installations can provide good control for a while and then cause problems. For this reason it is important to be sure all shields are properly installed.

External Speed Trim

A jumper must be connected between terminals 11 and 12 unless an optional remote Speed Trim potentiometer is used. If a Speed Trim potentiometer is used, connect it as shown in the plant wiring diagram, using shielded wire. A 100 ohm multiturn potentiometer will provide ±5% speed adjustment. Potentiometers of smaller values may be used if less adjustment is desired.

Speed and Phase Matching with an SPM-A Synchronizer

Connect the SPM-A (optional equipment) wires to terminals 15 (+/-) and 16 (com). use shielded wire and connect the shield to the ground.

Auxiliary Input

Terminals 17 (-) and 15 (+) are used for auxiliary input from a load sensor. Use of the load sensor and parallel lines allow the 2301A Speed Control to be used in isochronous load-sharing circuits. If the load sensor is not used, droop must be used to share the load. (An exception is a multiple engine installation in which one engine is operated isochronously and all other engines are operated in droop.)

Speed Sensor

Connect a speed-sensing device (a magnetic pickup (MPU) is normally used) to terminals 8 and 7. No polarity is observed. Use shielded wire and connect the shield only at the 2301A control. The shield must have continuity the entire distance to the MPU. The shield is to be insulated from all other conductors and from the MPU.

Installation Check-Out Procedure

When the installation is completed perform the following check-out procedure before beginning the start-up adjustments in Chapter 3.

1. Visual Inspection:

a. Check the linkage between the actuator and the prime mover for looseness or binding. Refer to the appropriate actuator manual, and Woodward Manual 25070, Electronic Control Installation Guide, for additional information on the linkage.

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WARNING-MINIMUM FUEL POSITION The actuator lever should be near, but not at, the minimum position when the fuel or steam rack is at the minimum position. This could avoid a dangerous condition caused by an engine which will not shut down.

b. Check for correct wiring according the plant wiring diagram.

c. Check for broken terminals and loose terminal screws. Make sure all terminal lugs are carefully and correctly installed. (Incorrectly installed crimp-on terminals can cause governor failure.)

d. Check the speed sensor (MPU) for visible damage. Check the clearance between the gear and the sensor, and adjust if necessary. See Woodward manual 82510 Magnetic Pickups and Proximity Switches for Electronic Controls.

2. Check for Grounds

With the power off, check for ground by measuring the resistance between each terminal and the grounding bolt located below terminal 9. Terminals 1 and 2 are power-input terminals. Either of the terminals may be grounded in accordance with local codes or through other equipment powered from the same supply. If either is grounded, a high resistance to ground will be evident at terminals 1 through 5 on low voltage models and terminals 1 through 4 on high voltage models. Grounds present on the terminals will not normally effect operation, unless they interfere with the input power or switch logic. Grounds on terminals 7 though 17, detected by readings other than infinity, should be located and removed.

Figure 2-3. Outline Drawing of 2301A Speed Control

Figure 2-4. Low Voltage Plant Wiring Diagram

Figure 2-5. High Voltage Plant Wiring Diagram