Installation Guide

TP-6906 4/1622 Section 1 Installation Instructions
1.4.7 Automatic Transfer Switch
Connection
Hazardous voltage.
Backfeed to the utility system can
cause property damage, severe
injury, or death.
If the generator set is used for
standby power, install an automatic
transfer switch to prevent inadvertent
interconnection of standby and
normal sources of supply.
WARNING
A typical standby system has an automatic transfer
switch connected to the generator set output to
automatically transfer the electrical load to the
generator set if the normal source fails. The normal
power source is typically utility power. When normal
power returns, the switch transfers the load back to the
normal power source and then signals the generator set
to stop.
Connect the ATS or remote start/stop switch. Connect
the load leads from the generator set to the Emergency
source lugs on the ATS. Connect the RBUS or engine
start connections as described below. Route
low-voltage communication leads through separate
conduit from the AC power and load leads. All
connections must comply with applicable state and
local codes.
Kohler Model RXT Automatic Transfer Switch
The RDC2 controller is designed to control the Kohler
Model RXT transfer switch as well as the generator set.
Follow the installation instructions to connect the
transfer switch interface board to the appropriate
terminals on the generator set. The RDC2 controller
uses a Kohler-proprietary communication protocol to
communicate with the transfer switch.
When connected to a Kohler Model RXT transfer switch,
the RDC2 controller provides the following features:
D Monitors and displays utility voltage and frequency.
D Schedule loaded exercises from the RDC2 generator
set controller.
D Set the ATS system voltage and frequency.
D Allows calibration of the utility voltage and frequency
at the generator set controller.
D Allows adjustment of transfer switch transfer time
delays from the generator set controller.
RBUS communication connections for a Kohlerr
Model RXT transfer switch
One Model RXT transfer switch can be connected to the
generator set. See Figure 1-11. Use shielded,
twisted-pair cable to c onnect P10-1 through P10-4 on
the transfer switch interface module to the generator set
terminal block connections A, B, PWR, and COM. See
Section 1.4.8 for communication cable
recommendations and maximum cable length.
The Model RXT transfer switch with the combined
interface/load management board requires one set of
RBUS connections to the generator set. However, the
combined board acts as two RBUS modules: one RXT
transfer switch and one load management device.
Note: Connections 3 and 4 on the generator set are not
used with the Model RXT transfer switch.