Why is a Transfer Switch
Needed?
When AC power fails, you rely on batteries to keep your system
running. Unfortunately, batteries have limited capacity.
Operation through extended outages demands a redundant source of AC
power.
Per National Electric Code and utility requirements, connecting
that redundant power source means installing a transfer switch to
prevent dangerous backfeeding into the dead utility line.
Why Cutler-Hammer?
Eaton’s Cutler-Hammer business is a world leader in transfer
switch design using technology gleaned from our renowned circuit
breaker family. This experience provides a family of transfer
switches featuring the industry’s highest interrupting and
short-time ratings. Our complete offering includes manual and
automatic transfer switches with open, closed and soft-load
switching.
We even reduce your cost by including required overcurrent
protection in the transfer switch, not as an add-on component
required by competitive solutions.
Options Available
For your lowest installed cost, specify open transition
switching. Specify closed transition switching for those
applications where you can’t tolerate extended HID lighting outages
caused by open transition switching of sources. Specify
soft-load transition to provide truly bumpless switching between
redundant sources.
Bumpless Soft-Load Transfer
Why is true bumpless switching needed? You know that any
power disturbance lasting more than 150 milliseconds depletes
battery capacitive storage and causes your batteries to begin to
discharge electrochemically. Each electrochemical discharge
and recharge cycle reduces the capacity of a battery. With
modern VRLA batteries limited to 400 charge/discharge cycles under
best-case conditions, reducing intentional switching disturbances
pays off quickly with increased battery life. In fact, battery
systems protected by a soft-load transfer switch can last two to
three times longer than batteries protected by ordinary open or
closed transition switches.
With labor and materials estimated at $4000 to replace a 4-string
48 volt DC supply, not including the hazardous material disposal
costs, double or triple battery life means that your battery
replacement charge is dramatically reduced. So a battery string that
was replaced every 3 years can now be replaced no sooner than every
6 years, putting in excess of $4000 back in your pocket. Larger
battery systems save even more!
|