Instructional Booklet
Page
16
Effective: July 2010
ATC-100 Contactor Based Transfer Switch
For more information visit: www.eaton.com
IB01602017E
5.3.1 Utility Power Source Failure
Standard Utility power source failure is defined as a reduction or
loss of voltage. If this occurs, the sequence of operation is as fol-
lows.
1. Failure of the Utility is detected by the controller intelligence.
2. When the controller detects a failure, the engine contacts
close or open (after delay if programmed) and start the
engine-driven generator.
3. When the Generator voltage reaches its operation rating, the
K2 relay closes, starting the transfer operation. This operat-
ing sequence causes the contactor to open the Utility and
close on Generator.
4. The load is now transferred to the Generator power source.
5.3.2 Utility Power Source Restoration
1. A return to the Utility power source begins when the voltage
in phase-to-phase in a single sensing unit is restored to a pre-
set value.
2. At the preset voltage, the controller will cause the K1 relay to
change state. This starts the return to the Utility power
source.
3. During this sequence, the contactor opens the Generator and
closes on the Utility.
4. Simultaneously, the engine cool-down timer initiates the shut
down of the engine driven generator.
5. Transfer of the load back to the Utility power source is now
complete.
Section 6: Testing and Problem Solving
6.1 Testing
After the ATS equipment is initially installed or during planned out-
ages, the installation should be tested to ensure that all equipment
operates properly. This attention to detail will help avoid unex-
pected malfunctions. Mechanical and/or electrical tests should be
performed as described in this section.
The frequency of subsequent testing should be based on recom-
mendations of the Genset manufacturer. Use the system test
pushbutton to check the electrical operation of the switch.
6.1.1 Mechanical and/or Electrical Testing
Energize the ATS equipment as described in Sections 6.1.2
through 6.1.6. Insure that all safety precautions are taken and
that all
WARNINGS
and
CAUTIONS
are observed.
6.1.2 No Voltage Steps
With no voltage available on either power source, proceed as fol-
lows.
Step 1:
The generator engine start controls should be in the OFF
position to prevent an undesired start.
Step 2:
Ensure that the Controller has been set to the proper
applied system voltage.
Step 3:
Check all ATS loads to ensure that they are ready to be
energized.
6.1.3 Connecting the Power Sources
Step 1:
Close the Utility power source upstream protection
device. The Utility power switching device should close.
Step 2:
Connect the engine start battery cable.
Step 3:
With the emergency generator in the OFF position, close
the Generator power source upstream protective device,
assuming such a device used.
WARNING
HIGH VOLTAGES ASSOCIATED WITH OPERATIONAL TRANSFER
SWITCH EQUIPMENT PRESENT A SHOCK HAZARD THAT CAN
CAUSE SEVERE PERSONAL INJURY OR DEATH. USE EXTREME CAU-
TION TO AVOID TOUCHING ELECTRICAL CONNECTIONS WHENEVER
INSPECTING OR TESTING THE EQUIPMENT.
IN ADDITION, IMPROPER OPERATION OF THE GENERATOR SET PRE-
SENTS A HAZARD THAT CAN CAUSE SEVERE PERSONAL INJURY
OR DEATH. OBSERVE ALL SAFETY PRECAUTIONS IN YOUR GENER-
ATOR SET OPERATIONS AND INSTALLATION MANUALS.
NOTICE
SINCE FEATURE 4 (TIME DELAY ENGINE COOL-OFF), AS DESCRIBED
IN SECTION 3, IS A STANDARD FEATURE, AN ENGINE START SIG-
NAL WILL BE PRESENT FOR A PERIOD OF TIME WHEN THE SWITCH
IS FIRST ENERGIZED. THE PERIOD OF TIME IS EQUAL TO THE TIMER
SETTING. TO AVOID STARTING THE ENGINE DURING THIS TIME
PERIOD, TURN THE GENERATOR CONTROLS TO THE OFF POSITION.
