Eaton Cutler-Hammer ATVSKDA30300XSU, Instructions Manual

Page: 30 / 40

I.B. ATS-V003
Page 24
Effective 6/98
5.4 NON-AUTOMATIC OPERATION (MANUALLY
OPERATED)
A non-automatic (manually operated) transfer switch
(Paragraph 1.2.1) functions as described in Paragraphs
5.1 through 5.3. All transfer operations are accom-
plished by true hand operation, with no power assis-
tance of any kind.
5.5 NON-AUTOMATIC OPERATION (ELECTRIC-
ALLY OPERATED)
A non-automatic (electrically operated) transfer switch
(Paragraph 1.2.1) functions similarly to the non-auto-
matic (manually operated) transfer switch except for the
addition of an electrical operating feature. This feature
permits the main contacts to be opened or closed elec-
trically. There is, however, no intelligence circuit associ-
ated with this design.
Electrical operation is accomplished by adding a motor
and required circuitry to the manual mechanism and wiring
it to a pushbutton on the front of the enclosure (Figure 5-
5). The pushbutton can be pushed to test the transfer
switch or held to make an electrical transfer. The switch’s
operating position can be visually indicated on the front of
the enclosure by using optional indicating lights.
Pushing and holding the pushbutton causes the motor
to operate and automatically transfer the load by open-
ing and closing the main contacts. Since an intelligence
circuit is not part of the design, operation of the pushbut-
ton is required each time an electrical transfer is
required, whether it is from Normal to Emergency or
vice versa.
5.6 AUTOMATIC TRANSFER SWITCH
The automatic transfer switch incorporates all the features
and utilizes the same designs as the switches described in
Paragraphs 5.4 and 5.5, except that intelligence and
supervisory capabilities are added to the switch by the
addition of a logic panel in the enclosure or on the enclo-
sure door (Figures 1-4 and 3-5). The logic panel can be as
sophisticated or simple as required, depending upon the
number and types of options selected.
The operating sequence of an automatic transfer switch
is dictated by the switch’s standard features and selected
options. Operation of an automatic transfer switch during
normal source failure and normal source restoration will
be described here with only standard options included on
the switch. Additional options, as described in the sepa-
rate instructional document dedicated to the specific
logic being used, can change sequences and timing,
depending upon the options selected. Refer to para-
graph 3.4. Become familiar with additional options select-
ed and their effect on the normal operation of an auto-
matic transfer switch.
Normal Power Source Failure
Standard normal power source failure is defined as a
reduction or loss of voltage. If this occurs, the sequence
of operation is as follows:
• Failure of the normal power source is detected by the
logic.
• When the logic detects a failure, it will close a contact
which starts the engine driven generator.
• When the emergency power source voltage and fre-
quency reaches its operation range, the logic begins
the transfer operation. This operating sequence
opens the Normal Power Source Switching Device
(NB) and closes the Emergency Power Source
Switching Device (EB).
• The load is now transferred to emergency power
source.
Figure 5-5 Electrical Operation Pushbutton and
Position Indicating Lights Shown Mounted