12
Operation
WARM UP TIME
Some applications require that the generator run for a given time
before a load is applied. This parameter allows the user to set that
time. Normally, it will be set to 10 seconds. The generator is ready
to accept load when this timer expires. This timer should be set to
zero for applications where the system needs to accept load within
10 seconds of utility loss.
ALARM HOLD OFF TIME
Once the engine has started, some alarm functions (such as low
oil pressure and under speed) are not activated immediately since
the engine must be given time to reach a stable condition. This
parameter determines the time that elapses before the hold off
alarms are activated.
LOAD ACCEPT FREQUENCY
This is the minimum frequency the generator must reach before the
system will accept load.
LOAD ACCEPT VOLTAGE
This is the minimum voltage the generator must reach before the
system will accept load.
LOW VOLTAGE LIMIT
This parameter sets the tolerance limits for utility voltage in a single
standby utility paralleling system. It does not apply to MPS paral-
leling generators.
HIGH VOLTAGE LIMIT
This parameter sets the tolerance limits for utility voltage in a single
standby utility paralleling system. It does not apply to MPS paral-
leling generators.
TARGET FREQUENCY
This parameter sets the nominal output frequency.
TARGET VOLTAGE SETPOINT
This parameter sets the nominal output AC voltage.
PROGRAMMABLE ALARM
SETPOINTS
Alarms can be setup for any analog input, digital input, or digital
output function. Each generator leaves the factory with the appro-
priate default settings. The settings can be modified in the field by
qualified technicians with the necessary security access via
GenLink™. It is strongly recommended that the default settings are
saved before changing them.
RUNNING HOURS
The PM-GC and the PM-PC keep track of how many hours the
engine has been running. This is displayed in hours and tenths of
hours. Any run of less than six minutes duration may not be
recorded. This parameter is for display only.
KILOWATT HOURS
The PM-GC and the PM-PC keep track of how many kWhs the
generator has output over the life of the generator and for the last
run cycle.
STANDBY OPERATION
In a MPS system, there are typically at least two generators. The
first unit to start when utility is lost will perform differently to the
other units. The first unit will close its contactor to a dead bus (the
generator bus). All following generators will have to synchronize
with the generator bus before closing their own contactor. There
are protection systems in place to prevent an out-of-phase transfer
occurring.
The PowerManager™ monitors utility voltage via the transfer
switches and when it detects a loss of utility voltage it signals the
PM-PC power modules to start. Full details of how the
PowerManager™ detects utility voltage and manages the power
module startup sequence may be found in the PowerManager™
manual. In a non-MPS system, the PM-GC monitors utility voltage
via the transfer switches. When it detects a loss of utility voltage, it
starts the generator.
MPS START SEQUENCE
The normal sequence for startup for a MPS system is as follows:
1. PowerManager™ detects loss of utility.
2. PowerManager™ starts all generators and connects the first
generator at rated speed, voltage, and frequency to the gen-
erator bus.
3. PowerManager™ then synchronizes the remaining generators
to the generator bus and closes their contactors. Generators
will parallel with each other when all of the following condi-
tions are met:
• The absolute difference in RMS volts between generators is
less than 6 volts.
• The phase angle difference of the generators voltage is less
than +/- 10 degrees and must stay in this condition for at
least 8 cycles.
• The generator that is synching to the bus must be between 0
and 0.2 Hertz faster than the frequency on the bus.
4. If utility has returned at this point, then no transfer takes place.
Otherwise, the utility contact is opened and the load is discon-
nected.
5. The PowerManager™ closes the generator supply to the load.
If utility returns, the generators will run together in parallel for
the minimum run period.
6. When PowerManager™ detects that utility supply has returned,
it opens the generator supply to load and then closes utility
supply to load.
7. After transferring back to utility, the generators will run for
either one minute or the remainder of the engine run time
(whichever is the longest time) with the generators still in
parallel. If the utility fails during this time, transfer immediately
(do not wait for line interrupt delay).
8. When in cooldown, if utility fails, apply the line interrupt delay
timer.
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