Asco 7000 Series User manual

ASCO 7000 SERIES ACTB
Automatic Closed-Transition Transfer &
Bypass-Isolation Switches
H design 600 through 1200 A
Operator’s Manual
381333-194 B
9/2016
DANGER is used in this manual to warn of a
hazard situation which, if not avoided, will result
in death or serious injury.
WARNING is used in this manual to warn of a
hazardous situation which, if not avoided, could
result in death or serious injury.
CAUTION is used in this manual to warn of a
hazardous situation which, if not avoided, could
result in minor or moderate injury.
Refer to the outline and wiring drawings provided with
your 7000 Series ACTB for all installation and
connection details and accessories.
Refer to Group 5 Controller User’s Guide 381333–126
for ATS status display messages, time delays, pickup &
dropout settings, and adjustments.
Rating Label
Each 7000 Series 7ACTB contains a rating label to
define the loads and fault circuit withstand/closing
ratings. Refer to the label on the Transfer Switch for
specific values.
Do not exceed the values on the rating label.
Exceeding the rating can cause personal injury
or serious equipment damage.
An experienced licensed electrician must install the
7ACTB.
600-1200 amp sizes

Operator’s Manual 7000 Series ACTB
2 381333-194 B
This page left blank intentionally.

7000 Series ACTB Operator’s Manual
381333-194 B 3
Table of Contents
Rating Label ............................................................................................................................................................. 1
Nameplate ................................................................................................................................................................ 4
Catalog Number Identification .................................................................................................................................. 4
Installation .................................................................................................................................................................. 5
Remove the Skid ...................................................................................................................................................... 5
Supporting Foundation ............................................................................................................................................. 5
Mounting ................................................................................................................................................................... 5
Line Connections ...................................................................................................................................................... 5
Testing Power Conductors ....................................................................................................................................... 5
Connecting Power Conductors ................................................................................................................................. 5
Controller Ground ..................................................................................................................................................... 5
Harnesses ................................................................................................................................................................ 5
Engine Starting Contacts .......................................................................................................................................... 6
Auxiliary Circuits ....................................................................................................................................................... 6
Functional Test ......................................................................................................................................................... 6
Functional Test – Voltage Checks............................................................................................................................ 7
Functional Test - -Electrical Operation .................................................................................................................... 8
Testing & Service ...................................................................................................................................................... 9
Transfer Test ............................................................................................................................................................ 9
Preventive Maintenance ........................................................................................................................................... 9
Replacement Parts ................................................................................................................................................... 9
Disconnecting the Controller .................................................................................................................................... 9
Manual Load Transfer .............................................................................................................................................. 9
Trouble-Shooting .................................................................................................................................................... 10
Maintenance Handle .............................................................................................................................................. 10
Bypassing & Isolating ............................................................................................................................................ 12
Bypassing the ATS ................................................................................................................................................. 12
To Bypass Normal Source ..................................................................................................................................... 13
To Bypass Emergency Source ............................................................................................................................... 13
Isolating the ATS .................................................................................................................................................... 14
Contact Inspection .................................................................................................................................................. 15
Return to Service .................................................................................................................................................... 16
To Un-Bypass Normal Source ................................................................................................................................ 18
To Un-Bypass Emergency Source ......................................................................................................................... 18
Index .......................................................................................................................................................................... 19

Operator’s Manual 7000 Series ACTB
4 381333-194 B
Nameplate
The Transfer Switch nameplate includes data for each
specific 7000 Series ACTB. Use the switch only within
the limits shown on this nameplate. A typical catalog
number is shown below with its elements explained.
Catalog Number Identification
Typical 7000 Series ACTB catalog no. for switched
neutral, 3 pole, 600 amp, 480 V, in Type 1 enclosure:
H7
A
CTB B 3 600 N 5 C
Frame &
Series
Neutral Phase
Poles
Amperes Voltage Controller Enclosure
A-solid
B-switch
blank- none
2-single
3-three
600
800
1000
1200
C 208
D 220
E 230
F 240
G 277
H 380
J 400
K 415
L 440
M 460
N 480
P 550
Q 575
R 600
5- standard
5X- if
accessories
ordered
C- Type 1
F- Type 3R
G- Type 4
L- Type 12
blank- open
type
Open-type H7ACTB with the lower door open (transfer switch shown).
Status
Lights
&
Engine
Control
Transfer
Switch
Isolation
Handle
Bypass
Handle
Transfer
Control
& Lights
Group 5
Controller

Installation Operator’s Manual
381333-194 B 5
Installation
ASCO 7000 Series Automatic Transfer & Bypass–
Isolation Switches (7ACTBs) are factory wired and
tested. Field installation requires mounting and
connection of service cables, and auxiliary control
circuits (if required).
Remove the Shipping Skid
Open the enclosure’s lower front door and also remove
the lower rear access panel. Then remove the four lag
screws (2 in front, 2 in rear) securing the enclosure to
the shipping skid.
Supporting Foundation
The supporting foundation for the enclosure must be
level and straight. Refer to the applicable enclosure
outline drawing included with the switch for all mounting
details including door opening space.
If bottom cable entry is used, the foundation must be
prepared so that the conduit stubs are located correctly.
Refer to the enclosure outline drawing for specified area
and location. Provide cable bending space and
clearance to live metal parts. When a concrete floor is
poured, use interlocking conduit spacer caps or a wood
or metal template to maintain proper conduit alignment.
Mounting
Refer to the applicable enclosure outline drawing
furnished with this switch and mount the automatic
transfer switch according to details and instructions
shown on diagram.
Line Connections
Refer to the Wiring Diagram provided with the switch. All
wiring must be made in accordance with the National
Electrical Code and local codes.
Do not remove the barrier from the transfer switch.
Always protect the transfer switch, bypass switch, and
isolation contacts and mechanisms from construction
grit and metal chips when cabling.
De–energize the conductors before making any line
or auxiliary circuitry connections. Be sure that
Normal and Emergency line connections are in
proper phase rotation. Place engine generator
starting control in the OFF position. Make sure
engine generator is not in operation.
Testing Power Conductors
Do not connect the power conductors to the transfer
switch until they are tested. Installing power cables in
conduit, cable troughs and ceiling-suspended hangers
often requires considerable force. The pulling of cables
can damage insulation and stretch or break the
conductor’s strands. For this reason, after the cables are
pulled into position, and before they are connected, they
should be tested to verify that they are not defective or
have been damaged during installation.
Protect the switch from construction grit and metal
chips to prevent malfunction or shortened life of the
7ACTB switch.
Connecting Power Conductors
After the power cables have been tested, connect them
to the appropriate terminal lugs on the bypass switch as
shown on the wiring diagram provided with the switch.
Make sure the lugs provided are suitable for use with the
cables being installed. Standard terminal lugs are
solderless screw type and will accept the wire sizes
listed on the drawings provided with the 7ACTB. Be
careful when stripping insulation from the cables; avoid
nicking or ringing the conductor. Remove surface oxides
from cables by cleaning with a wire brush. When
aluminum cable is used, apply joint compound to
conductors. Tighten cable lugs to the torque specified
on rating label.
Controller Ground
A grounding wire must be connected to the controller’s
lower left mounting stud. Because the controller is
mounted on the enclosure door, a conductive strap must
be used between the enclosure and the door. This
connection provides proper grounding which does not
rely upon the door hinges.
Harnesses
The transfer switch is connected to the left side of the
controller by a plug–in harness (two plugs).

Operator’s Manual Installation
6 381333-194 B
Installation
Engine Starting Contacts
All customer connections, including the engine control
contact connections, are located on terminal block TB
which is mounted on the top right side of the enclosure.
Refer to the wiring diagram provided with the automatic
transfer switch and connect the engine start wires to the
appropriate terminals. See Figure 1 and Table A.
Table A. Engine start connections.
When normal
source fails
Terminals on
transfer switch
contact closes TB1 and TB2
contact opens TB1 and TB3
Auxiliary Circuits
Connect auxiliary circuit wires to appropriate terminals
on transfer switch terminal block TB as shown on the
wiring diagram provided with this automatic transfer
switch.
Figure 1. Customer terminal block on the top right side
of the enclosure.
Functional Test
The Functional Test consists of two checks:
□ 1 - Voltage Checks, page 7
□ 2 - Electrical Operation, page 8
Do these checks in the order presented to avoid
damaging the ACTB.
Read all instructions on the Wiring Diagram and labels
affixed to the automatic transfer switch. Note the control
features that are provided and review their operation
before proceeding.
Continue to 1 – Voltage Checks on next page.
engine start
connections
on
customer
terminal
block TB

Installation Operator’s Manual
381333-194 B 7
Installation
Figure 2. Standard controls and indicators.
Functional Test
Read all instructions on the Wiring Diagrams and labels
affixed to the 7ACTB. Note the control features that are
provided and review their operation before proceeding.
After installing the 7ACTB check the following:
– Bypass Handle should be in the NORMAL position.
– Isolation Handle should be in the CONN position.
– CN transfer switch should be C (closed)
– CE transfer switch should be O (open)
If handles are not in correct positions, follow instructions for
Bypassing and Isolating the automatic transfer switch on
pages 12-18. Do not force the handles. Electrical
interlocks prevent a wrong sequence of operation.
1 – Voltage Checks
First check nameplate on transfer switch; rated voltage
must be the same as normal and emergency line voltages.
Use extreme caution when using a meter to
measure voltages. Do not touch power terminals;
shock, burns, or death could result!
Perform steps 1 through 6 at the right. Observe the status
lights. See Figure 2
■ Black square means light is on.
□ White square means light is off.
* If necessary, adjust voltage regulator on generator per the
manufacturer’s recommendations. The ACTB will respond
only to rated voltage specified on the nameplate.
Now continue to 2 – Electrical Operation on next page.
1
Close the normal source circuit
breaker. The Transfer Switch
Connected To Normal and the
Normal Source Accepted lights
should come on.
2
Use an accurate voltmeter to
check phase to phase and phase
to neutral voltages present at the
transfer switch normal source
terminals.
3
Close the emergency source
circuit breaker. Turn the Engine
Control switch to Run to start
the generator. The Transfer
Switch Connected To Normal &
Emergency Source Accepted
lights should come on.
4
Use an accurate voltmeter to
check phase to phase and phase
to neutral voltages present at the
transfer switch emergency
source terminals.*
5
Use a phase rotation meter to
check phase rotation of
emergency source; it must be
the same as the normal source.
6
Turn the Engine Control switch
to Auto to stop the generator.
The Emergency Source
Accepted light should go off.
Then put the starting control
selector switch (on the generator
set) in the automatic position.
Close the enclosure door.
observe
these lights

Operator’s Manual Installation
8 381333-194 B
Installation
Figure 3. Standard controls and indicators.
2 – Electrical Operation
This procedure checks electrical operation of the ACTS.
Close enclosure door before proceeding to prevent
personal injury in case of electrical system fault.
Transfer Test
The ATS should still be bypassed. Both normal and
emergency sources must be available and the emergency
source generator (if used) must be capable of being
started; put engine starting control in automatic position.
The Transfer Switch Connected to Normal light and the
Normal Source Accepted light should be on.
1. Turn the Isolation Handle counterclockwise to the
TEST position.
NOTE: The engine generator may be signaled to start
while turning the Isolation Handle. If emergency source is
available, the ATS may operate to the emergency position.
If it does, operate Retransfer Delay Bypass switch.
2. Perform steps 1–5 at right. Observe the status lights.
See Figure 3.
■ Black square means light is on.
□ White square means light is off.
3. Turn the Isolation Handle clockwise to the CONN
(connected) position.
4. Turn the Bypass Handle clockwise to the OPEN
position.
** If you do not want closed–transition transfer, press
the Closed Transition Bypass pushbutton while the
controller display shows Waiting for In–Sync. This
action causes open–transition (momentary load
interruption) transfer to the opposite source, if
conditions permit. Also refer to the Group 5 Controller
User’s Guide 381333–126.
1
The Transfer Switch Connected To
Normal and Normal Source
Accepted lights should be on.
2
Turn and hold Transfer Control
switch clockwise to Transfer Test
until the engine starts and runs
(within 15 sec.). Emergency
Source Accepted light should come
on.
3
Transfer switch CE closes and
then transfer switch CN opens
(closed–transition overlap). The
Transfer Switch Connected To
Emergency light should come on
and the Transfer Switch Connected
to Normal light goes off (you might
see and hear the brief overlap
transfer). **
4
Transfer switch will operate back to
Normal position after Feature 3A
time delay. For immediate
retransfer turn Transfer Control
counter-clockwise to Retransfer
Delay Bypass. The Transfer Switch
Connected To Normal light should
come on; Transfer Switch
Connected to Emergency light
should go off.
5
The engine–generator will stop
after the Feature 2E time delay
(unloaded running engine
cooldown). The Emergency
Source Accepted light should go
off.
This completes the Functional Test of the 7ACTB
observe
these lights operate
this switch

Testing & Service Operator’s Manual
381333-194 B 9
Testing & Service
TRANSFER TEST
Test the Automatic Transfer Switch portion of the 7000
Series 7ACTB at least once a month. This procedure
checks the electrical operation of the Transfer Switch and
Controller. Put the engine–generator starting control (at
the engine–generator set) in automatic mode.
In the following test the generator will start, the load will
be transferred to the Emergency source, then back to the
Normal source. With both sources available the load will
be transferred in a closed–transition mode.
Be sure to close the enclosure door before
proceeding to prevent personal injury in case of
electrical system fault.
Perform the five–step Electrical Operation – Transfer
Test procedure on page 8.
PREVENTIVE MAINTENANCE
Reasonable care in preventive maintenance will insure
high reliability and long life for the 7000 Series 7ACTB.
An annual preventive maintenance program is
recommended.
ASCO Power Services, Inc. is ASCO Power
Technologies service organization for the United
States and Canada. Call 1-800-800-2726 (ASCO) to
request a service call and information on preventive
maintenance agreements.
Annual Inspection Checklist
Hazardous voltage capable of causing shock,
burns, or death is used in this switch. Deenergize
both Normal & Emergency power sources before
performing inspections!
□ Cleaning the 7ACTB enclosure
Brush and vacuum away any excessive dust
accumulation. Remove moisture with a clean cloth.
□ Check the transfer switch contacts.
Bypass, isolate, and withdraw the transfer switch.
Then remove the transfer switch interphase barriers
and check the condition of the contacts. Replace
contacts when pitted or worn excessively. Reinstall
the interphase barriers carefully. See page 15
□ Maintain transfer switch lubrication.
If switch is subjected to severe dust or abnormal
operating conditions, renew factory lubrication on all
movements and linkages. Relubricate solenoid
operator if TS coil is replaced. Don’t use oil; order
lubrication kit 75-100
□ Check all cable connections & retighten them.
REPLACEMENT PARTS
Replacement parts are available in kit form. When
ordering parts provide the Serial No., Bill of Material No.
(BOM), and Catalog No. from the transfer switch
nameplate. Contact your local ASCO Power
Technologies Sales Office or ASCO Power Services,
Inc.
In the United States and Canada
call 1 – 800 – 800 – ASCO ( 2726 )
DISCONNECTING THE CONTROLLER
The harness disconnect plugs are furnished for repair
purposes only and should not have to be unplugged. If
the controller must be isolated, follow these steps.
Bypass–Isolation Switch is energized! Do not
touch isolation contact fingers; shock, burns, or
death could result!
Disconnecting the Plugs
1. Bypass and Isolate the Automatic Transfer Switch.
2. Open the upper enclosure door.
3. Separate the two quick disconnect plugs by
squeezing the latches. Do not pull on the harness
wires.
Reconnecting the Plugs
1. The ATS should be still bypassed and isolated.
2. The two harness plugs and sockets are keyed.
Carefully align the plugs with the sockets and press
straight in until the latches click.
3. Close the enclosure doors.
4. Follow Return to Service instructions on page 16.
MANUAL LOAD TRANSFER
This procedure manually transfers load to other source if
the Transfer Switch or Control Panel are out of service.
Close enclosure doors to prevent personal
injury in case of electrical system fault.
1. Bypass the connected ACTB source. Turn Bypass
Handle to EMERGENCY or NORMAL (page 13).
2. Isolate to Test. Turn the Isolation Handle to TEST
position (see page 14).
3. Turn the Bypass Handle to OPEN, then to the other
source (see page 12). The load will be interrupted.
4. Turn the Isolation Handle clockwise to the CONN
[connected] position (see page 15).

Operator’s Manual Testing & Service
10 381333-194 B
Testing & Service
TROUBLE-SHOOTING
Note any optional accessories that may be furnished on the
7ACTB and review their operation. Refer to any separate
drawings and/or instructions that may be packed with the
7ACTB. See Table B.
Hazardous voltage capable of causing shock, burns,
or death is used in this switch. Do not touch the
power or load terminals of the bypass switch or
transfer switch!
Table B. Trouble-Shooting Checks.
PROBLEM CHECK IN NUMERICAL SEQUENCE
1 OPERATION 2 GEN-SET 3 VOLTAGE
Engine–generator set does
not start when the Transfer
Control switch is turned
and held in Transfer Test
position or when normal
source fails.
Hold Transfer Test switch 15
seconds or the outage must be
long enough to allow for Feature
1C time delay plus engine
cranking and starting time.
Starting control must be in the
automatic position. Batteries
must be charged and
connected. Check wiring to
engine starting contacts.
-
Transfer switch does not
transfer the load to the
emergency source after the
engine–generator set starts.
Wait for Feature 2B time delay to
time out (if used)
Generator output circuit breaker
must be closed. Generator
frequency must be at least 95%
of nominal (57 Hz for a 60 Hz
system.) *
Voltmeter should read at least
90% of nominal phase to
phase voltage between
transfer switch terminals EA
and EC (or EL1 and EL2 for 2
pole switches). *
Transfer switch does not
transfer the load to normal
source when normal returns
or when the Transfer
Control switch is released.
Wait for Feature 3A time delay to
time out (if used)
-
Voltmeter should read at least
90% of nominal phase to
phase voltage between
transfer switch terminals NB
and NC, NC and NA, and NA
and NB (or NL1 and NL2 for 2
pole switches).
Engine–generator-set does
not stop after load retransfer
to the normal source.
Wait for Feature 2E time delay to
time out (if used)
Starting control must be in the
automatic position. -
Failure to Synchronize
light comes on.
Conditions of Normal or Emergency Sources not suitable for closed transition transfer.
Recheck voltage and frequency of both sources. Press Alarm Reset pushbutton.
Extended Parallel Time
light comes on.
CN and CE contacts are closed longer than setting in the Controller. Open the disconnected source
circuit breaker, then call your nearest ASCO Service Center for assistance.
TS Locked Out
light comes on.
Transfer lockout operation has occurred; transfer switch is disabled from automatic operation. Open
the disconnected source circuit breaker, then call your nearest ASCO Power Services, Inc. for
assistance
These are factory settings. Refer to the Controller User’s Guide.
If the problem is isolated to circuits on the controller or the transfer switch, call your local ASCO Power Technologies
sales office or ASCO Power Services, Inc.: in the United States or Canada, call 1–800–800–2726. Furnish the Serial No.,
Catalog No., and Bill of Material (BOM) No. from the transfer switch nameplate.

Testing & Service Operator’s Manual
381333-194 B 11
MAINTENANCE HANDLE
Bypass and isolate the Transfer Switch before using
the maintenance handle! See pages 12-15.
Remove the maintenance handle after using it;
store it inside.
1. Bypass, isolate, and withdraw the transfer switch
(pages 12 through 15). Then locate and remove the
maintenance handle from the clip (inside lower left
side). Insert the handle onto the shaft on the left side
of the operator of the transfer switch See Figures 4,
5, 6 and Table C.
2. Move the maintenance handle up or down as shown
to manually operate the transfer switch. Operate
both upper and lower contact shafts. Observe the
window indicators (right side). Remove the
maintenance handle and store it on the lower left
side.
Figure 4. Contact position indicators
Table C. Maintenance handle positions
ATS Position Handle Indicators
Normal
E = O
upper contacts
open
N = C
lower contacts
closed
Emergency
E = C
upper contacts
closed
N = O
lower contacts
open
Note: If Normal and Emergency connections are
reversed this operation is also reversed.
Figure 4. Maintenance handle operation for Emergency source contacts (upper shaft).
Figure 5. Maintenance handle operation for Normal source contacts (lower shaft).
Emergency contacts
(upper shaft)
window
indicators
O is open
C is closed
Normal contacts
(lower shaft)
contact
position
indicators
(right side)
UP opens the
Emergency source
contacts
DOWN closes the
Emergency source
contacts
UP closes the
Normal source
contacts
DOWN closes the
Normal source
contacts
UPPER SHAFT
LOWER SHAFT

Operator’s Manual Bypassing & Isolating
12 381333-194 B
Bypassing & Isolating
Figure 7. Status lights and Engine Control.
Upper green light is
on if Transfer Switch
is on Normal.
Lower red light is on
if Transfer Switch is
on Emer
g
enc
y
.
Figure 8. Status lights for Transfer Switch main
contact position.
Upper amber
light should be
on.
Figure 9. Status lights for Transfer Switch isolation
contact position.
BYPASSING THE ATS*
This procedure explains how to Bypass the closed
transfer switch contacts. Bypassing is required before the
Transfer Switch can be tested or isolated. The Bypass
Switch Handle must be in the OPEN position (green
window indicator) and the Isolation Handle must be in the
CONN [connected] position (window indicator). The TS
Connected light must be on. See Figures 7, 8, and 9.
You can only bypass to the same source that the
Transfer Switch is connected. Solenoid interlock
prevents incorrect operation.
1. Observe which Transfer Switch Connected To light
is on (Normal or Emergency) on the door. This is the
position of the transfer switch (see Figure 8).
2. Follow the directions on next page to Bypass to the
same source as connected to transfer switch (select
Normal or Emergency).
Window
indicator
shows yellow
when ATS is
bypassed to
Emergency.
Window
indicator
shows green
when the ATS
is
not bypassed.
Window
indicator
shows yellow
when ATS is
bypassed to
Normal.
Figure 10 Bypass Handle and
three position window indicators.
Allowable Positions of the Bypass Switch
in relation to Positions of the Transfer Switch
(with Isolation Handle in the Conn [connected]
position and TS Connected light on)
Transfer Switch Bypass Switch
can be in eithe
r
If Transfer Switch is in
Normal position Open or Normal
If Transfer Switch is in
Emer
g
enc
y
position. Open or Emergency

Bypassing & Isolating Operator’s Manual
381333-194 B 13
Bypassing & Isolating
To Bypass Normal Source*
(Load connected to Normal Source)
The Transfer Switch Connected To Normal light is on
and Transfer Switch Connected To Emergency light is
off.
Push in the handle and
turn it counterclockwise.*
Push in* the Bypass Handle all the way, then turn it
counterclockwise until Bypass Switch Position shows
closed on NORMAL (yellow window indicator). The green
light Bypassed to Normal will come on and the amber
light Not In Automatic will flash.
Figure 11. Bypass to Normal diagram.
Upper green
light comes on.
Lower window indicator
NORMAL
shows yellow
Figure 12. Status light and window indicator for
Bypassed to Normal Source.
To Bypass Emergency Source*
(Load connected to Emergency Source)
The Transfer Switch Connected To Emergency light is
on and Transfer Switch Connected To Normal light is
off.
Turn the handle clockwise.*
Turn* the Bypass Handle clockwise until Bypass Switch
Position shows closed on EMERGENCY (yellow window
indicator). The red light Bypassed to Emergency will
come on and the amber light Not In Automatic will flash.
Figure 13. Bypass to Emergency diagram.
Lower red
light comes on.
Upper window indicator
EMERGENCY
shows yellow
Figure 14. Status light and window indicator for
Bypassed to Emergency Source.
The automatic transfer switch can now be put in the TEST or OPEN position. See ISOLATING on page 14.
* NOTE: When Accessory 40*B (reversed Normal & Emergency connections)
is specified, the handle operation is reversed. Follow instructions on the door.

Operator’s Manual Bypassing & Isolating
14 381333-194 B
Bypassing & Isolating
ISOLATING THE ATS
Isolating is required before any service work can be
performed on the automatic transfer switch (ATS). Refer
to Figures 15, 16, 17 and 18.
1. Bypass the closed automatic transfer switch
contacts. See BYPASSING on pages 12 and 13.
2. Turn the Isolation Handle counterclockwise (approx.
8 turns) until window shows TEST. The TS Test
amber light should come on. The ATS can be tested
now without load interruption (see page 9).
Figure 15. CONNECTED to TEST position.
Middle amber
light should be
on.
position
window
CONN
TEST
ISOLATE
counterclockwise –
draws
out the transfer switch
Figure 16. Isolation Handle turned to TEST.
NOTE: In the TEST position the transfer switch
solenoid operator circuit is energized through
secondary disconnects.
Hazardous voltage capable of causing electrical
shock, burns, or death; do not touch any control
circuit terminals.
3. Continue turning Isolation Handle counterclockwise
(approx. 6 turns) until the window shows ISOLATE.
The TS Isolated amber light should come on.
Figure 17. TEST to ISOLATE position.
Lower amber
light should be
on.
position
window
CONN
TEST
ISOLATE
counterclockwise –
draws
out the transfer switch
Figure 18. Isolation Handle turned to ISOLATE

Bypassing & Isolating Operator’s Manual
381333-194 B 15
Bypassing & Isolating
4. Open the lower enclosure door. Pull out both left
and right side rails then use the two tab handles to
roll out the transfer switch. It can be safely
inspected in this position. The transfer switch can
also be removed for easier maintenance operations.
See Figure 19.
Hazardous voltage capable of causing electrical
shock, burns, or death; do not touch any control
circuit terminals
Figure 19. .Transfer switch isolated
and pulled out for inspection.
See page 10 for maintenance handle use. A lifting yoke
734408 is available to facilitate lifting by using an
overhead crane or similar equipment. See WARNING
The Transfer Switch weighs 165–235 lbs.
depending upon the number of poles. Use lifting
device 734408 or other device capable of lifting
this weight to avoid personal injury or equipment
damage. Two persons are recommended
Contact Inspection
The main contacts are protected by arcing contacts. The
arcing contacts make first and break last to avoid arcing
at the main contacts. Contact condition should be
checked annually. Contacts should be replaced when
contact material becomes severely worn. Discoloration is
normal. Do not file contacts because it wastes material.
Instead use light emery paper to clean up the contact
surfaces.
If the contacts need to be replaced see page 10
To prevent the possibility of fatal electrical shocks
and burns, bypass, isolate, and withdraw the
transfer switch before working on it.
The contact assemblies (two for each pole) are located
to the right of the operator mechanism.
1. Deenergize transfer switch (pages 12 thru 15)
Bypass, isolate, and withdraw transfer switch. Use a
voltmeter to verify that no electrical power is present
at the transfer switch terminals.
2. Use the maintenance handle (page 10).
Open the contacts that will be inspected by using
the detachable maintenance handle.
3. Remove the interphase barriers (Figure 20).
Use a blade screwdriver to loosen (ccw) four
round–head screws holding each barrier to the arc
chutes. Slide barrier up until keyholes clear the
round–head screws, then remove it.
Figure 20. Interphase barrier removal
4. Remove the arc chutes.
Use a 5/8” nutdriver to remove (ccw) two long
insulator nuts. Then pull the arc chute outward
(off the long threaded rods). See Figure 20.
handles
left rail right rail

Operator’s Manual Bypassing & Isolating
16 381333-194 B
Bypassing & Isolating
5. Remove the movable contact cover.
Use your thumb and fingers to squeeze the sides
inward until the contact cover is released from the
shaft clamp (both sides). Then remove the movable
contact cover. See Figures 21 and 22.
Figure 21. Movable contact cover release
Figure 22. Movable contact cover removal
6. Reinstall the movable contact cover.
After inspection reinstall the movable contact cover
onto the movable contact assembly. Use your
thumb and fingers to squeeze the sides inward until
the contact cover is latched onto the metal bracket
(both sides). Figures 21 & 22.
7. Reinstall the arc chute.
Slide the arc chute (arc splitters toward the contacts
and recess for nuts outward) between the two long
threaded rods. Reinstall the two long insulator nuts
(round shoulder in) and use a 5/8” nutdriver to
GENTLY tighten (cw) until snug. Do not overtighten
these nuts. See Figure 20.
8. Reinstall the interphase barrier.
Install the barrier over the arc chutes and slide
it up until the four round–head screws align in the
four keyholes in the barrier. Then slide the barrier
down. Use a blade screwdriver to tighten (cw) the
four round–head screws to secure the barrier to the
arc chute insulator nuts. See Figure 20.
RETURN TO SERVICE
This procedure explains how to return the automatic
transfer switch (ATS) to service after inspection and
maintenance. Observe the Bypass Switch Position
indicator and lights).
1. Use the two tab handles to roll the transfer switch into
the enclosure (isolation contacts facing inward) until
the crank bearings stop against the draw–in plates.
Next push in both side rails and close the enclosure
door.
Figure 23. Transfer switch isolated
and pulled out for inspection.
Close the enclosure door to prevent personal injury
in case of electrical system fault.
2. Turn Isolation Handle clockwise (approx. 6 turns)
until the window shows TEST and TS TEST light
comes on.
Figure 24 ISOLATE to TEST position.
shaft clamp
Movable contact cover
Squeeze movable
contact cover to
release it
right rail
left rail
handles

Bypassing & Isolating Operator’s Manual
381333-194 B 17
Bypassing & Isolating
Middle amber light
should come on.
position
window
CONN
TEST
ISOLATE
clockwise – draws in
the transfer switch
Figure 25 Isolation Handle turned to TEST
3. The ATS can be tested now without load
interruption (see page 9).
Solenoid interlock prevents you from closing the
isolation contacts until the ATS is in the same
position as the Bypass Switch.
4. Observe which Bypass Switch Position window
indicator is yellow (NORMAL or EMERGENCY) at
the Bypass Switch Handle. This indicates the source
connected to the load.
5. Observe which Transfer Switch Connected To light
is on (Normal or Emergency) on the door. This is the
position of the Transfer Switch. If it is not in the same
position as the Bypass Handle change the position
of the Transfer Switch as follows:
To change the position of transfer switch
Operate to NORMAL Operate to EMERGENCY
Turn Transfer Control
switch to Retransfer
Dela
y
B
y
pass.
Turn Transfer Control
switch to Transfer Test
(
hold 15 seconds
)
.*
Connected To Normal
li
g
ht should come on.
Connected To Emergency
li
g
ht should come on.
* If Feature 2B time delay is used, there will be a delay
before transfer to Emergency
NOTE: With Normal available, the automatic transfer
switch will not stay in the emergency position unless
Feature 3A time delay is used (at least 30 seconds).
Do not close the isolation contacts unless
the Transfer Switch (ATS) and Bypass Switch are
in the same position!
6. When the transfer switch is in the same position as
the Bypass Switch handle, continue turning the
Isolation Handle clockwise (about 8 turns) until the
window shows CONN (connected).
Figure 26. TEST to CONN (connected) position.
Upper amber
light should be
on.
position
window
CONN
TEST
ISOLATE
clockwise – draws in
the transfer switch
Figure 27. Isolation Handle turned to CONN

Operator’s Manual Bypassing & Isolating
18 381333-194 B
Bypassing & Isolating
RETURN TO SERVICE continued*
This procedure explains how to return the Bypass Switch
Handle to the OPEN position. The Bypass Handle must
be in the CLOSED position (yellow indicator on NORMAL
or EMERGENCY) and the Isolation Handle must be in
the CONN position (window). See Figures 28, 29 and 30.
You can only bypass to the same source that the
ATS is connected. Solenoid interlock prevents
incorrect operation.
1. Observe which Bypass Switch Position indicator is
yellow (NORMAL or EMERGENCY) at the Bypass
Switch Handle. This indicates the source
connected to the load.
2. Un–Bypass to same source as the Bypass Switch
Position as follows (select Normal or Emergency).
To Un–Bypass Normal Source*
(Load connected to Normal Source)
The Transfer Switch Connected To Normal light is on
and Transfer Switch Connected To Emergency light is
off.
Turn the handle clockwise.*
Turn* the Bypass Handle clockwise until the Bypass
Switch Position shows OPEN (green window indicator).
The Bypassed to Normal light should go off and the Not
In Automatic light should go off.
Figure 29. Un–Bypass Normal diagram.
Window
indicator
shows yellow
when ATS is
bypassed to
Emergency.
Window
indicator
shows green
when the ATS
is
not bypassed.
Window
indicator
shows yellow
when ATS is
bypassed to
Normal.
Figure 28. Bypass Handle and window indicators.
To Un–Bypass Emergency Source*
(Load connected to Emergency Source)
The Transfer Switch Connected To Emergency light is
on and Transfer Switch Connected To Normal light is
off.
Turn the handle counterclockwise.*
Turn* the Bypass Handle counterclockwise until the
Bypass Switch Position shows OPEN (green window
indicator). The Bypassed to Emergency light should go
off and the Not In Automatic light should go off.
Figure 30. Un–Bypass Emergency diagram.
The Automatic Transfer & Bypass–Isolation Switch should be left in this position.
* NOTE: When Accessory 40*B (reversed Normal & Emergency connections) is specified,
the handle push–pull operation is reversed. Follow instructions on the door.

Operator’s Manual Index
381333-194 B 19
INDEX
A
auxiliary circuits, 6
B
barriers, interphase, 15. 16
bypassing the ATS, 12, 13
C
catalog number, 4
cleaning, 9
closed transition bypass, 8, 9
connections
power, 5
contact inspection, 15, 16
controller
disconnecting, 9
see Controller User’s Guide
E
electrical operation, 8
Emergency Source Accepted light,
7
engine starting contacts, 6
extended parallel time, 10
F
foundation, 5
frequency, generator, 10
functional test, 6, 7, 8
H
harness, 6
disconnect plugs, 9
help
[e-mail]
800–800–ASCO (2726)
I
inspection, 12
installation, 5
interphase barriers, 15, 16
isolating the ATS, 14, 15
L
lifting device, transfer switch, 15
lights, 6, 7, 12, 13, 14
load connected to emergency, 7
load connected to normal, 7
lubrication, 9
M
maintenance, preventive, 9
maintenance handle, 11
warning, 11
manual load transfer, 11
warning, 11
N
nameplate, 4
Normal Source Accepted light, 7
O
operation
electrical, 8
manual, 11
warning, 11
P
parts, 9
phase rotation, 7
preventive maintenance, 9
problem, 10
R
rating label, 1
replacement parts, 9
return to service, 16, 17, 18
S
service
ASCO Power Services, Inc., 9
settings
see Controller User’s Guide
T
test, functional, 6, 7, 8
testing power cables, 5
time delays, 9
see Controller User’s Guide
Transfer Control selector switch
Retransfer Delay Bypass, 7
Transfer Test, 7
Transfer Switch Connected To
Emergency light, 7
Transfer Switch Connected To
Normal light, 7
transfer test, 8, 9
transfer to emergency, 8, 9
transfer to normal, 8, 9
troubleshooting, 10
TS locked out, 10
V
voltage checks, 7
voltage, pickup and dropout settings
see Controller User’s Guide

Printed in U.S.A.
ASCO Power Technologies
160 Park Avenue
Florham Park, NJ 07932-1591 USA
Phone: [phone] (ASCO) for sales or service
www.ascopower.com
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