Woodward EGCP-2 - Speed Bias Output

Manual 26086 EGCP-2 Engine Generator Control Package
Woodward 101
Operations Affected
The Bus PT Scale calibration will affect the Voltage matching accuracy when the
generator is paralleling to other generators on the isolated bus (Bus PT
monitored), or when the generator is paralleling to the mains (Mains PT
monitored). Improper calibration of the Bus PT sensing of the EGCP-2 may
cause large reactive load swings when paralleling into the bus or mains when the
generator breaker closes.
Alarms Affected
The Bus PT scale calibration will affect the Mains High and Low Voltage Limit
alarm setpoints in the Shutdown and Alarms tuning menu. If the Bus PT scale is
improperly calibrated, the sensed voltage for these high and low alarm setpoints
may cause alarms and/or loss of mains action to occur at the wrong voltage
levels.
Speed Bias Output
The Speed Bias Offset calibration point sets an offset on the speed bias output of
the EGCP-2. This output is fed into the speed control governor to bias the
governing speed for synchronization and load control functions. This offset is the
starting point from which the EGCP-2 begins all of its speed biasing operations.
The Speed Bias Offset value is factory calibrated for 0.0 Vdc.
Usually the speed bias output should remain at the factory calibrated level. The
speed control governor is used to set the synchronous speed of the generator,
and no additional bias is required.
However, if interfacing the EGCP-2 with speed controls other than those
manufactured by Woodward Governor Company, an offset may be required for
proper operation.
Increasing the Speed Bias Offset will increase the Speed Bias readout in the I/O
Display status menu of the EGCP-2. The speed bias offset imposes an offset in
percent of speed bias output. For example a Speed Bias offset of 3% will give a
3% speed bias reading in the I/O Display status menu. Decreasing the Speed
Bias Offset has just the opposite effect in that the values will read negative
instead of positive.
When initially powered up, the EGCP-2 will always apply the value for the speed
bias offset to the speed bias output. With the factory settings, the speed bias
output should always go to 0.0 Vdc on initial power up.
Speed bias offset will affect the bus frequency of a single unit machine operating
on an isolated bus. Speed bias offset will also affect the load sharing between
machines operating on an isolated bus. It is recommended that the speed bias
output be calibrated for 0% ( 0.0 Vdc) when using Woodward Governor speed
controls.