Product Manual

TP-6807 12/11 21Section 3 Operation
Section 3 Operation
3.1 Model RXT Transfer Switch
Operation
The Model RXT transfer switch must be connected to a
generator set equipped with the RDC2 or DC2
controller. The RDC2/DC2 generator set/transfer
switch controller manages automatic transfer switch
(ATS) functions when connected to a Kohlerr Model
RXT transfer switch through the ATS interface board.
The controller receives voltage sensing data from the
Model RXT ATS and operates the generator set and
transfer switch to provide standby power when utility
power is lost.
See the generator set operation manual for:
D ATS status screens and configuration menus.
D Information about loaded exercise.
3.2 Source Availability
The Model RXT transfer switch supplies voltage
sensing data to the RDC2 or DC2 controller through the
ATS interface board. If the source voltage falls below
the undervoltage dropout setting, the source is
considered to have failed. See Figure 3-1.
Voltage Sensing Parameter Setting
Accuracy ±5%
Undervoltage Dropout 90% of Pickup
Undervoltage Pickup 90% of Nominal
Figure 3-1 Voltage Sensing Parameters
3.3 ATS Control Sequence of
Operation
See Figure 3-2 for time delay settings.
Preferred Source Fails:
1. The load control contact opens.
2. The engine start time delay times out.
3. The generator set is signaled to start.
4. The generator starts and the emergency source
becomes available.
5. The normal-to-emergency time delay times out.
6. The transfer switch transfers to the emergency
source.
7. The load control contact time delay times out.
8. The load control contact closes.
Normal Source Returns:
1. The emergency-to-normal time delay times out.
2. The contactor transfers to the normal source.
3. The engine cooldown time delay times out.
4. The generator is signaled to stop.