TP-6126 8/0242 Section 6 Accessories
GM21287
Figure 6 -2 Preferred Source Selector Switch
Operating Modes. The transfer switch is factory-set for
the generator set-to-utility mode of operation. This
mode uses one generator set, which is connected to the
Emergency side of the contactor (Source E), and one
engine start relay. The engine start relay connections
are located on the contactor on 30--400 amp units, and
on the c ustomer-connection terminal block on larger
units (see Section 2.5.2). The engine start contact is
assigned to the c onnected generator set and does not
change assignment when the preferred source switch
position is changed. In this mode, if the preferred source
switch is set to Source E, then the system operates the
generator set indefinitely, transferring to utility power
only if the generator set fails.
Use the setup program to change the mode to generator
set-generator set or utility-utility if necessary. The
generator set-generator set mode uses two generator
sets and requires the assignment of a second engine
start output. Use the setup program to assign one of the
main logic board terminal strip or I/O module outputs to
Start Source N Generator, and connect the engine start
leads for the Source N generator set to the
corresponding terminals on the terminal strip or I/O
module terminals. See Sections 3.3.2 and 6.5.2. The
programmed engine start output remains tied to the
Source N generator set regardless of the position of the
preferred source switch.
The utility-utility mode is designed to use utility power for
both Source N and Source E. This mode does not use
the engine start outputs.
Time Delays and Source Parameters. Engine start
relays and time delays, source voltage and frequency
trip points, and load shed time delays are assigned to
the source (N or E). They do not change assignment
when the preferred source switch position is changed.
Note: Source N is always connected to the Normal side
of the transfer switch, and Source E is always
connected to the Emergency side.
Other time delays are assigned to the source function
(preferred or standby). System parameters that are
assigned to the function automatically change source
when the preferred source selection changes.
Figure 6-3 shows which parameters are assigned to the
source and which are assigned to the function. The last
two columns of the table show the effect of the preferred
source selector switch position on each parameter or
time delay.
To Next Page
Loading...
