WOODWARD调速器说明书01301

Application

Note

Adjustment of SPM-A Synchronizer to

Lean-burn, Spark-ignited Gas Engines

Application Note 01301!WARNING

Read this entire manual and all other publications pertaining to the work to be performed before installing, operating, or servicing this equipment. Practice all plant and safety instructions and precautions. Failure to follow instructions can cause personal injury and/or property damage.

The engine, turbine, or other type of prime mover should be equipped with an overspeed (overtemperature, or overpressure, where applicable) shutdown device(s), that operates totally independently of the prime mover control device(s) to protect against runaway or damage to the engine, turbine, or other type of prime mover with possible personal injury or loss of life should the mechanical-hydraulic governor(s) or electric control(s), the actuator(s), fuel control(s), the driving mechanism(s), the linkage(s), or the controlled device(s) fail.

!CAUTION

To prevent damage to a control system that uses an alternator or battery-charging device, make sure the charging device is turned off before disconnecting the battery from the system.

!CAUTION

Electronic controls contain static-sensitive parts. Observe the following precautions to prevent damage to these parts.

• Discharge body static before handling the control (with power to the control turned off, contact a grounded surface and maintain contact while handling the control).

• Avoid all plastic, vinyl, and styrofoam (except antistatic versions) around printed circuit boards.

• Do not touch the components or conductors on a printed circuit board with your hands or with conductive devices.

Woodward Governor Company reserves the right to update any portion of this publication at any time. Information provided by Woodward Governor Company is believed to be correct and reliable. However, no responsibility is assumed by Woodward Governor Company unless otherwise expressly undertaken.

© 1991 by Woodward Governor Company

All Rights Reserved

Application Note 01301 Adj. SPM-A to Lean-burn Gas Engines Woodward 1Decreasing Match-Up Window Size (Time) to

Shorten Automatic Synchronization Delay on

Unstable, Lean-Burn, Spark-Ignited Gas Engines

It sometimes takes an excessive amount of time for an SPM-A automatic

synchronizer to parallel two lean-burn gas engines together or to parallel the local bus to the utility bus.

Synchronizing times can be significantly shortened by reducing the dwell time

(match-up time) setting controlled by a dip switch on the printed-circuit board

inside the synchronizer case.

Dwell time is set for 1/2 second at the factory. This means that the phase angle must remain in the control's synchronizing window for 1/2 second before a

synchronize order will be issued by the SPM-A.

This time can be reduced to 1/4 or 1/8 of a second to allow the synchronizer to become more easily satisfied if the engine-generator phase is moving into and out of the phase-matching window due to engine misfiring and rough idle.

The change in phase window length is made necessary by the inherent engine instability on some lean-burn gas engines. The phase window should be set for the maximum amount of time possible to minimize transient current when the breaker closes.

!WARNING

Reducing the dwell time may cause higher transient currents when the

breaker closes. This could damage the generator, the breakers, or cause personal injury.

Another method of improving synchronization on engine/governor systems that are very sensitive at high idle is to reduce the SPM-A gain. This is normally

accomplished by turning the gain adjust potentiometer on the SPM-A

counterclockwise. In some cases of poor system dynamics on lean-burn gas

engines, the gain may still be too high, even with the gain potentiometer full

CCW.

In these cases we recommend additional gain reduction by adding a series

resistance between terminal 22 on the SPM-A and the ± connection on the 2301A Load Sharing and Speed Control or Generator Load Sensor.

Adj. SPM-A to Lean-burn Gas Engines Application Note 01301 2Woodward

Dwell Time Adjustment Procedure

The dwell time, often referred to as match-up time, is factory set at 1/2 second.To set the dwell time for one of the other settings (1/8, 1/4 or 1 second) perform the following procedure:

1.

Turn off the power and all voltage inputs to the synchronizer.2.Remove the four elastic hex nuts securing the synchronizer cover. Remove the cover.

!CAUTION

To prevent damage to the components of the synchronizer, do not touch any part of the circuit board unless adequately grounded against static

discharge. Follow instructions provided in Woodward manuals 82715 and 82384.

NOTE

To minimize circuit breaker stress it is best to use the longest possible dwell time that still gives acceptable synchronizing times. Try Synchronizing at the 1/2 second dwell time before trying the 1/4 second or 1/8 second settings.

Dwell-Time Setting Switches

3.Set the dwell time using the four-position gang switch located in the upper

left corner of the circuit board. The settings are as follows:

Dwell Time

Seconds

Switch 1Switch 2Switch 3Switch 4One-eighth Seconds (1/8)

ON Off Off Off One-quarter Seconds (1/4)

Off ON Off Off One-half Second (1/2)

Off Off ON Off One Second (1)Off Off Off ON

4.Replace the cover and secure with the four elastic hex nuts.

Synchronizer Gain Reduction Procedure

If the governor response to the synchronizer output signal is too sensitive, even

with the SPM-A gain adjustment potentiometer fully ccw, and if the actuator-to-

carburetor linkage is optimized and non-linear (see manual 25014 and the

appropriate governor manual), it may be necessary to reduce the electrical signal

between the SPM-A and the governor or load sensor. This will, in effect, add

additional gain adjustment to the SPM-A.

To add gain adjustment:

1.Turn off the power and all voltage inputs to the synchronizer, or turn the

synchronizer mode switch (terminals 10–13) to the OFF position.

2.Temporarily wire in a 250 k , at least 1/4 W potentiometer as shown.

Using a Potentiometer to Reduce Gain in an SPM-A

3.Turn the SPM-A gain potentiometer back to the mid position, turn the

externally wired potentiometer full cw, and turn the stability adjustment to

mid position.

4.Turn the synchronizer switch to the check position (terminal 11 closed to

terminal 13) and start the engine.

5.Adjust the externally added potentiometer slowly ccw until gain is reduced to

an acceptable level and the synchronizer begins to hold the synchroscope

within the phase window at 12 o'clock. Switch from CHECK to OFF to

CHECK several times and fine tune the SPM-A gain and stability

adjustments of optimal synchronizing with minimal overshoot.

6.Shut down the engine. If desired, the external potentiometer can be carefully

removed, resistance measured, and replaced with an appropriate fixed

resistor of the nearest value. It may be necessary, after replacement, to

again fine tune the synchronizer's Gain and Stability as in step 5. Woodward3Adj. SPM-A to Lean-burn Gas Engines Application Note 01301 Unloaded steady-state dynamics of some lean-burn gas engines are so poor

that the best the synchronizer can do is close the breaker as the

synchroscope passes through the acceptable phase window. In these cases,

all sections of the fuel system should be looked at and optimized for

maximum steady-state performance.

Parts of the fuel system which can Affect stability include, but are not limited to:

• Actuator to carburetor linkage

• Carburetor adjustments

• Carburetor selection

• Carburetor bearings

• Air/Fuel ratio control

• Gas supply and differential pressures

• Actuator selection

• Spark plugs

• Ignition system

• Ignition timing

• Waste gate settings

• Governor settings

• Fuel Quality

4Woodward

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Woodward Governor Company

Attention: Technical Publications

PO Box 1519

Fort Collins CO 80522-1519, USA

Please include the manual number from the front cover of this publication.

Industrial Controls

Woodward Governor Company, PO Box 1519 (1000 East Drake Road), Fort Collins CO 80522-1519, USA

Phone (1)(970) 482-5811 • Fax (1)(970) 498-3058

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Woodward Governor Company, PO Box 3800 (3800 North Wilson Avenue), Loveland CO 80539-3800, USA

Phone (1)(970) 663-3900 • Fax (1)(970) 962-7050

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