Specifications

June 2007 PIP ELSAP20
Low-Voltage Automatic Transfer Switch
4.3.3 Main contacts shall be manually driven.
4.3.4 Electrical ratings of the bypass-isolation switch shall be equal to or greater
than the associated automatic transfer switch.
4.3.5 Separate bypass and isolation handles shall be used to provide clear
distinction between the functions. Handles shall be permanently affixed and
operable without opening enclosure doors.
4.3.6 The bypass switch handle shall have the following operating modes:
a. Bypass to Normal
b. Automatic
c. Bypass to Alternate
4.3.7 Operating speed of the bypass contacts shall be the same as the automatic
transfer switch and independent of the speed at which manual handle
operates.
4.3.8 The isolation switch handle shall have the following operating positions:
a. Automatic / Closed
b. Test
c. Isolated / Open
4.3.9 “Test” position shall permit testing the automatic transfer switch without
disturbing power to the load.
4.3.10 “Isolated / Open” position shall completely isolate the automatic transfer
switch from both lines and load without removing line and load conductors.
4.3.11 When in the “Isolated / Open” position, it shall be possible to completely
withdraw the automatic transfer switch for inspection and maintenance.
4.3.12 When the isolation switch is in the “Test” or “Isolated / Open” position, the
associated bypass switch shall function as a manual transfer switch to permit
load transfer to either source of power regardless of the position or condition
of the transfer switch.
4.4 Microprocessor Controllers
4.4.1 Microprocessor based controller(s) shall be capable of operating at the
ambient conditions specified on the purchaser’s PIP ELSAP20D Data Sheet.
4.4.2 Control module(s) shall be provided with protective covers, mounted
separately from transfer switch mechanism, and shall be easily disconnected
for routine maintenance.
4.4.3 Unless otherwise specified on the purchaser’s PIP ELSAP20D Data Sheet,
RS 485 interface for serial communication shall be provided
.
4.4.4 Purchaser connections shall be wired to a common terminal block to simplify
field-wiring connections.
4.4.5 LCD displays and keypads for viewing data and setting operational
parameters shall be provided as integral parts of controllers for viewing data
and setting operational parameters.
Process Industry Practices Page 5 of 10