Brochures and Data Sheets

Page 10
Custom Applications
Selective load systems allow one load at a time to be operated
when normal power fails. The system uses the minimum amount
of auxiliary power for operation so the alternate power source can
be sized for only one load at a time. The selective load system can
be designed to handle any number of loads in any combination of
sizes to suit the customers needs.
The only interfacing between the ASCO selective load system and
the load controls are power cables.
The system can be used with any electrical load application where
only one load out of a number of loads are to be operated from the
alternate power source at one time. A typical application is with
multiple banks of elevators when you want to enable only one
elevator at a time to operate under emergency conditions.
The system can be supplied with a separate control panel, which
allows loads to be selected from a remote location.
Figure 15 shows a typical selective load system with transfer
switches for five loads. The control panel has a selector switch
and position indication of each load.
Selective Load System
Transfer Switch with Distribution System
Transfer switches can be provided with normal and
emergency circuit breakers for overcurrent
protection, plus any combination of distribution
circuit breakers, bolted pressure switches, or
fusible disconnect switches.
Figure 16 shows a switchboard containing a circuit
breaker on the normal source of the automatic
transfer switch plus a distribution panelboard of
molded case circuit breakers to protect critical
downstream loads. The cubicle on the left end of
the system provides monitoring and control of the
distribution system.
Fig. 16 Transfer switch with distribution.
Fig. 15 Selective load system.