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Woodward governor spm-a speed phase match 9905-001
GOOD USED WOODWARD SPM-A PULLED FROM A WORKING SYSTEM THAT WAS UPGRADED. 90 DAY WARRANTY WITH USED PARTS
The SPM-A Synchronizer biases the speed of an off-line generator set so that
the frequency and phase match those of another generator or the utility bus.
Then it automatically issues a contact closure signal to close the circuit breaker
between the two when frequency and phase are matched within limits for a
The SPM-A is a phase-locked-loop synchronizer and strives for a perfect match
of frequency and phase. The SPM-A Synchronizer with voltage matching
generates additional raise and lower signals (relay contact closures) to the
generator's voltage regulator. Voltages must match within the SPM-A's tolerance
before breaker closure occurs.
For single-unit synchronization, installation of one synchronizer on each
generator allows each unit to be individually paralleled to the bus. For multipleunit
synchronization, one synchronizer can synchronize up to seven paralleled
generator units simultaneously to another bus.
Both synchronizers versions have three output options: high impedance, low
impedance, and EPG. Select the high impedance output for single-unit
synchronization when the engine is controlled by a Woodward 2301 control.
Select the low impedance output for single-unit synchronization when the engine
is controlled by a Woodward 2301A, 2500, or Electrically Powered Governor
(EPG) control through a Generator Load Sensor. Use the EPG output when
using a Woodward EPG control without load sensing. Both units have the
1/8, 1/4, 1/2, or 1 second dwell time (internally switch selectable, factory set
The SPM-A Synchronizer with voltage matching has a 1% voltage match as
standard. See the part number chart for other options.
Part Number Frequency Phase Angle Voltage Matching
Manual 82384 SPM-A Synchronizer
This section describes the general theory of operation of the two versions of the
SPM-A Synchronizer. Figure 1-1 shows the SPM-A Synchronizer with voltage
matching. Figure 1-2 shows a typical synchronizer system block diagram. Figure
1-3 shows a functional block diagram of the synchronizer.
The SPM-A Synchronizer checks the phase angle and frequency of the bus and
an off-line generator which is to be paralleled. The voltage inputs from the bus
and generator are first applied to separate signal conditioner circuits. Each signal
conditioner is a filter which changes the shape of the voltage input signals so
they can be accurately measured. A phase offset potentiometer in the signal
conditioner circuit is adjusted to compensate for phase errors. (This adjustment is
factory set with identical bus and generator inputs. It should be readjusted only
where a phase offset has been caused through the line transformers of the
installation.) The signal conditioners also amplify the bus and generator signals
and apply them to the phase detector.
A user-installed mode switch (single-pole, four-position) controls the relay driver.
The switch must be wired to synchronizer contacts 10 through 13 (see the plant
wiring drawing). The four positions are OFF, RUN, CHECK, and PERMISSIVE.
When the switch is OFF, the synchronizer is out of operation.
The RUN mode allows normal synchronizer operation and breaker closure
signals. The speed bias circuit continues to operate to maintain synchronization
for one second to allow time for the breaker closure signal. When one second
has elapsed, the lockout circuit activates to disable the synchronizer. The lockout
circuit is reset automatically when the relative phase angle exceeds the window
limit after the generator is disconnected from the bus.
The CHECK mode allows normal synchronizing and voltage matching, but does
not permit a breaker closure signal.
The PERMISSIVE mode allows synchronizer checks for proper synchronization,
but synchronizer operation does not affect the engine's speed (nor voltage, in the
voltage matching version). If phase and frequency are within proper limits, the
synchronizer issues the breaker closure command. (Voltage is not checked in the
See Woodward Application Note 50511 for information on the prediction of the
phase angle at paralleling breaker closure.
