Cutler-Hammer ATVISPE31000XSU, Instructions Manual

Page: 8 / 44

I.B. ATS-SD02
Page 2
Effective 5/98
1.2.1 TRANSFER SWITCH TYPES
In general, there are four types of basic transfer switch
equipment:
Automatic Transfer Switch
Automatic transfer switches automatically perform the
transfer function. They consist of three basic elements:
(1) Main contacts to connect and disconnect the load
to and from the source of power.
(2) Intelligence/supervisory circuits to constantly moni-
tor the condition of the power sources and thus pro-
vide the intelligence necessary for the switch and
related circuit operation.
(3) A transfer mechanism to effect the transfer of the
main contacts from source to source.
Basic Transfer Switch
The basic transfer switch is designed for use with cus-
tomer furnished logic. It is similar in design to the auto-
matic version except the intelligence circuit (logic panel)
and voltage selection panel are omitted. All automatic
sensing devices, relays or solid state devices are the
customer’s responsibility.
Non-Automatic Transfer Switch (Manually Operated)
Non-Automatic transfer switches provide the main con-
tacts and the transfer mechanism to effect the transfer
of the main contacts from source to source. Transfer of
power, however, is accomplished by true hand opera-
tion (not power assisted) of the transfer switch. This
switch is similar to the basic switch in that an intelli-
gence circuit and a motor driven mechanism are not
part of the design.
Non-Automatic Transfer Switch (Electrically
Operated)
This transfer switch is similar to the Non-Automatic
Transfer Switch (Manually Operated) just described
except that an electrical operation feature is added. The
switch electrically transfers power when an appropriate
pushbutton on the front of the enclosure is pushed. If
necessary, the switch can also be operated manually.
In addition to the four basic switch types just discussed,
there is a specialized design called the Bypass
Isolation Transfer Switch.
Bypass Isolation Transfer Switch
The bypass isolation switch is designed for applications
where maintenance, inspection and testing must be per-
formed while maintaining continuous power to the load
(Figures 1-2 and 1-3). This is typically required in criti-
cal life support systems and standby power situations
calling for safe system maintenance with no power dis-
ruptions. Such a design allows for the quick removal of
the different switching devices for inspection, mainte-
nance or replacement.
The automatic transfer switch, non-automatic transfer
switch (electrically operated) and bypass isolation trans-
fer switch are the available types for the configuration
described in this manual.
Operation of the automatic transfer switch and the
bypass isolation switch are only discussed in this manu-
al (Sections 5 and 7 respectively).
1.2.2 DESIGN CONFIGURATION
The Cutler-Hammer transfer switch is a rugged, compact
design utilizing insulated case switches or insulated case
circuit breakers to transfer essential loads from one
power source to another (Figures 1-2 and 1-4). Switching
devices are interlocked to prevent both switching devices
from being closed at the same time. The versatile design,
in addition to standard transfer functions, offers an option-
al integral thermal and short circuit protection in either or
both switching devices.
Figure 1-1 Typical Load Transfer Switch (circuit break-
er type) Schematic
Normal
Source
Emergency
Source
Load