ASCO POWER TECHNOLOGIES 7000 Series User manual

381333–193 D
Florham Park, New Jersey 07932–1591 USA
Sales or service call 1 800 800–2726 (ASCO) www.ascopower.com
Operator’s
Manual
7000 Series 7ATB
Automatic Transfer &
Bypass–Isolation Switches
H & P design 600 through 1200 A
DANGER is used in this manual to warn of high
voltages capable of causing shock, burns, or death.
WARNINGisusedinthismanualtowarn
of possible personal injury.
CAUTIONisusedinthismanualtowarn
of possible equipment damage.
600–1200 amp. sizes
Refer to the outline and wiring drawings provided
with your 7000 Series ATB 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.
An experienced licensed electrician must install the
7ATB.
Rating Label
Each 7000 Series 7ATB 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.
TABLE OF CONTENTS
section-page
INSTALLATION
Mounting 1-1.............................
Power Connections 1-1....................
Engine Starting & Auxiliary Circuits 1-2......
Functional Test 1-2, 1-3, 1-4.................
TESTING & SERVICE
Transfer Test 2-1..........................
Preventive Maintenance 2-1................
Disconnecting the Controller 2-1............
Manual Load Transfer 2-2..................
Trouble-Shooting 2-2......................
BYPASSING & ISOLATING
Bypassing the ATS 3-1, 3-2.................
Isolating the ATS 3-3, 3-4...................
Return to Service 3-5, 3-6, 3-7...............
INDEX back cover.........................

Nameplate
The Transfer Switch nameplate includes data for each
specific 7000 Series ATB. 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 ATB catalog no. for overlapping
neutral, 3 pole, 600 amp, 480 V, ATS in Type 1 enclosure:
H&P 7
A
TB C 3 600 N 5 C
Phase Poles
Neutral
A–solid
C– overlapping
Amperes Voltage Controller Enclosure
B–switched 5X –if
accessories
ordered
5–standard
G–type4
C–type1
F–type3R
L–type12
3–threeØ
2–singleØ
D220
C208
E230
K415
M460
J400
L440
N480
G277
F240
H380 Q575
P550
R600
1200
1000
800
blank – none
blank – open type
600
Design prefix
Transfer
Switch
Bypass
Handle Group 5
Controller
Transfer
Control
&Lights
H7ATB with the lower door open (transfer switch shown).
Isolation
Handle
Status
Lights
&
Engine
Control

SECTION 1 INSTALLATION
1 --- 1
ASCO 7000 Series Automatic Transfer & Bypass–
Isolation Switches (7ATBs) 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
spaceandclearancetolivemetalparts. Whena
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
shownondiagram.
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 interphase barriers from the transfer
switch. Always protect the transfer switch, bypass switch,
and isolation contacts and mechanisms from construc-
tion 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 gen-
erator 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 7ATB 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 7ATB. 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).

INSTALLATION (continued)
1--2
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
1–1 and Table A.
Table A. Engine start connections.
When normal source
fails
Te r m i n a l s o n
Te r m i n a l B l o c k T B
contact closes TB1 and TB2
contact opens TB1 and TB3
Note: To temporarily disable engine control from
the automatic transfer switch you can unplug J3
from the small P3 receptacle at the bottom of the
assembly. BesuretoreconnectplugJ3totheP3
receptacle for automatic transfer switch operation.
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.
engine start
connections
on
customer
terminal
block TB
Figure 1-1. Customer terminal block on the top right
side of the enclosure.
Functional Test
The Functional Test consists of two checks:
1—VoltageChecks,page1–3
2 — Electrical Operation, page 1–4
Do these checks in the order presented
to avoid damaging the 7ATB.
Read all instructions on the Wiring Diagram and labels
affixed to the automatic transfer & bypass–isolation
switch. Note the control features that are provided and
review their operation before proceeding.
Continue to 1–VoltageChecks on next page.

INSTALLATION (continued)
1 --- 3
observe
these lights
Tra nsf e r Swi t ch
Connected
To
Normal
Tra nsf e r Swi t ch
Connected
To
Emergency
Normal
Source
Accepted
Emergency
Source
Accepted
Tra nsf e r
Control
Retransfer
Delay
Bypass
Tran sf er
Test
HOLD FOR
15 SECONDS
RED
RED
GREEN
GREEN
()
Figure 1-2. Standard controls and indicators.
Functional Test
Read all instructions on the Wiring Diagrams and labels
affixed to the 7ATB. Note the control features that are
provided and review their operation before proceeding.
After installing the 7ATB check the following:
– Bypass Handle should be in the NORMAL position.
– Isolation Handle should be in the CONN position.
– TS transfer switch Normal contacts should be C(closed)
Emergency contacts should be O(open)
If handles are not in correct positions, follow instructions
for Bypassing and Isolating the automatic transfer switch
in Section 3.Do not force the handles. Electrical
interlocks prevent a wrong sequence of operation.
1–VoltageChecks
First check nameplate on transfer switch; rated voltage
mustbethesameasnormalandemergencylinevoltages.
Useextremecautionwhenusingameter
to measure voltages. Do not touch power
terminals; shock, burns, or death could result !
Perform steps 1–6 at the right. Observe the status lights.
See Figure 1–2.
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 7ATB 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 pres-
entatthetransferswitchnormal
source terminals.
3
Close the emergency source
circuit breaker. (Start generator,
if necessary.) 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 pres-
ent at the transfer switch emer-
gency source terminals.*
5
Useaphaserotationmeterto
check phase rotation of emer-
gency source; it must be the
same as the normal source.
ABC
6
Shut down the engine–genera-
tor, if applicable. The Emergen-
cy Source Accepted light should
go off. Then put the starting
control selector switch (on the
generator set) in the automatic
position. Close enclosure door.

INSTALLATION (continued)
1--4
observe
these lights
Tra nsf e r Swi t ch
Connected
To
Normal
Tra nsf e r Swi t ch
Connected
To
Emergency
Normal
Source
Accepted
Emergency
Source
Accepted
Tra nsf e r
Control
Retransfer
Delay
Bypass
Tran sf er
Test
HOLD FOR
15 SECONDS
RED
RED
GREEN
GREEN
()
operate
this switch
Figure 1-3. Standard controls and indicators.
2 – Electrical Operation
This procedure checks electrical operation of the ATS.
Be sure to close the 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: Theenginegeneratormaybesignalled
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 1–3.
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.
This completes the Functional Test of the 7ATB.
1
The Transfer Switch Connected
to Normal and Normal Source
Accepted lights should be on.
2
Turn a nd hold Tra nsf er Co ntrol
switch clockwise to Transfer
Test until the engine starts
and runs (within 15 sec.). The
Emergency Source Accepted
light should come on.
3
Transfer switch will operate to
the Emergency position after
Feature2Btimedelay.The
Transfer Switch Connected To
Emergency light should come
on and Load Connected to
Normal light goes off.
4
Transfer switch will operate
back to Normal position after
Feature3Atimedelay.Forim-
mediate retransfer turn Transfer
Control counterclockwise 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 cool-
down). The Emergency Source
Accepted light should go off.

SECTION 2 TESTING & SERVICE
2--1
TRANSFER TEST
Test the Automatic Transfer Switch portion of the 7000
Series 7ATB at least once a month. This procedure
checks the electrical operation of the Transfer Switch
and Controller. Put the engine–generator starting con-
trol (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. An interruption to the load will occur, un-
less the the Transfer Switch contacts are bypassed before
the test. See pages 3–1 through 3–4 for bypassing & iso-
lating instructions if no interruption of load is required.
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
Tes t procedure on page 1–4.
PREVENTIVE MAINTENANCE
Reasonable care in preventive maintenance will insure
high reliability and long life for the 7000 Series 7ATB.
An annual preventive maintenance program is recom-
mended.
ASCO Services, Inc. is ASCO Power Technologies’s
national service organization. In the US ASI can be
contacted at 1-800-800-2726 for information on pre-
ventive maintenance agreements.
Checklist for Yearly Inspection
Hazardous voltage capable of causing shock,
burns, or death is used in this switch.
Deenergize both Normal – Emergency power
sources before performing inspections!
Clean the 7ATB enclosure.
Brush and vacuum away any excessive dust accu-
mulation. Remove any moisture with a clean cloth.
Check the transfer switch contacts.
Bypass, isolate, and withdraw the transfer switch.
Then remove the transfer switch interphase barri-
ers and check the condition of the contacts. Re-
place contacts when pitted or worn excessively. Re-
install the interphase barriers carefully, page 3–4.
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 920799.
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 Technolo-
gies Sales Office or ASI:
In the United States
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 squeez-
ing 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 3–5.
MANUAL LOAD TRANSFER
This procedure manually transfers load to other source if
the Transfer Switch or Controller are out of service.
Close enclosure doors to prevent personal
injury in case of electrical system fault.
1. Bypass the connected ATB source. Turn Bypass Han-
dle to EMERGENCY or NORMAL (see page 3–2).
2. Isolate to Test. Turn the Isolation Handle to TEST
position (see page 3–3).
3. Turn the Bypass Handle to OPEN, then to the other
source (see page 3–1). The load will be interrupted.
4. Turn the Isolation Handle clockwise to the CONN
[connected] position (see page 3–4).

TESTING & SERVICE (continued)
2--2
TROUBLE-SHOOTING
Note any optional accessories that may be furnished on
the 7ATB and review their operation. Refer to any
separate drawings and/or instructions that may be
packed with the 7ATB. 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
Feature1Ctimedelayplus
engine cranking and starting.
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.
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 &
EC (or EL1 & EL2 for 2 pole)*
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.
–
Voltmeter should read at least
90% of nominal phase to
phase voltage between
transfer switch terminals NB &
NC, NC & NA, & NA & NB (or
NL1&NL2for2pole).
Engine–generator-set does
not stop after load retransfer
to the normal source.
Wait for Feature 2E time delay
to time out.
Starting control must be in the
automatic position. –
* These are factory settings. Refer to Controller’s User’s Guide.
If the problem is isolated to circuits on the controller or transfer switch, call your local ASCO Power Technologies
sales office or ASI: in the United States, call 1–800–800–2726. Furnish the Serial No., Catalog No., and Bill of
Material (BOM) No. from the transfer switch nameplate.
MAINTENANCE HANDLE
Bypass and isolate the Transfer Switch before
using the maintenance handle! See pages 3–1
through 3–4. Remove the maintenance handle
after using it; store it inside.
1. Bypass, isolate, and withdraw the transfer switch
(pages 3–1 through 3–4). Then locate and remove
the maintenance handle from the clip (inside lower
left side). Insert the handle into the hole in the
molded hub on the left side of the operator of the
transfer switch See Figure 2–1 and Table C.
Table C. Maintenance handle positions.
ATS Position Handle Indicators
Normal
E
N
up E=O
upper contacts open
N=C
lower contacts closed
Emergency
E
Ndown
E=C
upper contacts closed
N=O
lower contacts open
handle
shaft
frame window
indicators
Ois open
Cis closed
Emergency
contacts
Normal
contacts
contact
position
indicators
(right side)
UP closes the
Normal source
contacts (lower)
DOWN closes the
Emergency source
contacts (upper)
Figure 2–1. Maintenance handle operation and contact position indicators.

SECTION 3 BYPASSING & ISOLATING
3--1
Figure 3–1. Status lights and Engine Control.
TRANSFER SWITCH
CONNECTED TO NORMAL
CONNECTED TO EMERGENCY
Lower red light is on if
Transfer Switch is on
Emergency.
Upper green light is on
if Transfer Switch is on
Normal.
Figure 3–2. Status lights for Transfer Switch main
contact position.
TS CONNECTEDUpper amber light
should be on.
TS TEST
TS ISOLATED
Figure 3–3. 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 3–1, 3–2, 3–3.
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 3–2).
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 green when
the ATS is not
bypassed.
Window indicator
shows yellow
when ATS is
bypassed to
Emergency.
Window indicator
shows yellow
when ATS is
bypassed to
Normal.
Figure 3–4. 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
canbeineither
If Transfer Switch is in
Normal position. Open or Normal
If Transfer Switch is in
Emergency position. Open or Emergency

BYPASSING & ISOLATING (continued)
3--2
To Bypass Normal Source* To Bypass Emergency Source*
(Load connected to Normal Source)
The Transfer Switch Connected To Normal light is on
and Transfer Switch Connected To Emergency light is off.
(Load connected to Emergency Source)
The Transfer Switch Connected To Emergency light is on
and Transfer Switch Connected To Normal light is off.
Push in thehandleand
turn it counterclockwise.* Turnthehandleclockwise.*
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.
E
L
N
Push in
Bypass
Handle
and
turn it
counter-
clockwise.
ATS
Bypass Switch
Figure 3–5. Bypass to Normal diagram.
BYPASS SWITCH
BYPASSED TO NORMAL
BYPASSED TO EMERGENCY
Upper green
light comes on
Lower window indicator
NORMAL shows yellow
Figure 3–6. Status light and window indicator for
Bypassed to Normal Source.
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.
E
L
N
ATS
Bypass Switch
Turn
Bypass
Handle
clock-
wise.
Figure 3–7. Bypass to Emergency diagram.
BYPASS SWITCH
BYPASSED TO NORMAL
BYPASSED TO EMERGENCY
Lower red
light comes on
Upper window indicator
EMERGENCY shows yellow
Figure 3–8. 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 3–3.
*NOTE: When Accessory 40*B (reversed Normal & Emergency connections)
is specified, the handle operation is reversed. Follow instructions on the door.

BYPASSING & ISOLATING (continued)
3--3
ISOLATING THE ATS
Isolating is required before any service work can be
performed on the automatic transfer switch (ATS). Refer
to Figures 3–9, 3–10, 3–11, and 3–12.
1. Bypass the closed automatic transfer switch contacts.
See BYPASSING on pages 3–1 and 3–2.
2. Turn the Isolation Handle counterclockwise (approx.
8 turns) until window shows TEST.TheTS Test amber
lightshouldcomeon.TheATScanbetestednow
without load interruption (see page 2–1).
E
L
N
Automatic Transfer Switch
Bypass Switch
Turn crank
counter-
clockwise
until
window
shows
TEST.
Figure 3–9. CONNECTED to TEST position.
TS CONNECTED
Middle amber light
should be on. TS TEST
TS ISOLATED
position
window
CONN
TEST
ISOLATE
counterclockwise – draws
out the transfer switch
Figure 3–10. 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.
E
L
N
Turn crank
counter-
clockwise
until
window
shows
ISOLATE.
Automatic Transfer Switch
Bypass Switch
Figure 3–11. TEST to ISOLATE position.
TS CONNECTED
Lower amber light
should be on.
TS TEST
TS ISOLATED
position
window
CONN
TEST
ISOLATE
counterclockwise – draws
out the transfer switch
Figure 3–12. Isolation Handle turned to ISOLATE.

BYPASSING & ISOLATING (continued)
3--4
4. Open the lower enclosure door. Pull out both left and
right side rails then use the two 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 3–13.
Hazardous voltage capable of causing
electrical shock, burns, or death;
do not touch any control circuit terminals.
right railleft rail
handles
Figure 3–13.Transfer switch isolated
and pulled out for inspection.
See page 2–2 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 130–200 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 2–1.
The Service Bulletin is 381339–237.
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 3–1 thru 3–4)
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 2–2).
Open the contacts that will be inspected by using
the detachable maintenance handle.
3. Removetheinterphasebarriers(Figure 3–14).
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.
loosen (ccw)
round–head screws
(do not remove)
interphase barrier
arc chutes
keyslots
loosen (ccw)
round–head screws
(do not remove)
keyslots
insulator nuts
Figure 3–14. 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 3–14.

BYPASSING & ISOLATING (continued)
3--5
5. Remove the movable contact cover.
Useyourthumbandfingerstosqueezethesides
inward until the contact cover is released from the
shaft clamp (both sides). Then remove the
movable contact cover. See Figures 3–15 & 3–16.
squeeze movable
contact cover to
release it
Figure 3–15.
Movable contact
cover release.
movable contact cover
shaft clamp
Figure 3–16. 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 3–15 & 3–16.
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 3–14.
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 3–14.
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 indica-
tor and lights).
1. Use the two handles to roll the transfer switch into
the enclosure (isolation contacts facing inward) until
its crank pins engage the latch plates on both sides.
Next push in both side rails and close enclosure door.
right railleft rail
handles
Figure 3–17.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.
E
L
N
Turn crank
clockwise
until
window
shows
TEST.
Automatic Transfer Switch
Bypass Switch
Figure 3–18. ISOLATE to TEST position.

BYPASSING & ISOLATING (continued)
3--6
TS CONNECTED
Middle amber light
should come on. TS TEST
TS ISOLATED
position
window TEST clockwise – draws in
the transfer switch
Figure 3–19. Isolation Handle turned to TEST.
3. The ATS can be tested now without load interruption
(see page 2–1).
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 indica-
tor is yellow (NORMAL or EMERGENCY)atthe
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 Transf er Co ntro l
switch to Retransfer
Delay Bypass.
Turn Transf er Co ntro l
switch to Transfer Test
(hold 15 seconds).*
Connected To Normal
light should come on.
Connected To Emergency
light should comes 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).
E
L
N
Automatic Transfer Switch
Bypass Switch
Turn crank
clockwise
until
window
shows
TEST.
Figure 3–20. TEST to CONN (connected) position.
TS CONNECTED
Upper amber light
should be on.
TS TEST
TS ISOLATED
position
window CONN clockwise – draws in
the transfer switch
CONN
Figure 3–21. Isolation Handle turned to CONN.

BYPASSING & ISOLATING (continued)
3--7
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 NOR-
MAL or EMERGENCY) and the Isolation Handle must
be in the CONN position (window). See Figures 3–22,
3–23, and 3–24.
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)attheBypass
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).
Indicator shows
green when the ATS
is not bypassed.
Indicator shows
yellow when ATS
is bypassed to
Emergency.
Indicator shows
yellow when ATS
is bypassed to
Normal.
Figure 3–22. Bypass Handle and position indicators.
To Un–Bypass Normal Source* To Un–Bypass Emergency Source*
(Load connected to Normal Source)
The Transfer Switch Connected To Normal light is on
and Transfer Switch Connected To Emergency light is off.
(Load connected to Emergency Source)
The Transfer Switch Connected To Emergency light is on
and Transfer Switch Connected To Normal light is off.
Turnthehandleclockwise.* Turnthehandlecounterclockwise.*
Turn* the Bypass Handle clockwise until the Bypass
Switch Position shows OPEN (green window indicator).
The Bypassed to Normal lightshouldgooffandtheNot
In Automatic light should go off.
E
L
N
Turn
Bypass
Handle
clockwise.
ATS
Bypass Switch
Figure 3–23. Un–Bypass Normal diagram.
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.
E
L
N
ATS
Bypass Switch
Turn
Bypass
Handle
counter-
clockwise.
Figure 3–24. 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.

INDEX
Printed in U.S.A. Copyright 2015 ASCO Power Technologies, L.P.
A
auxiliary circuits, 1–2
B
barriers, interphase, 3–4, 3–5
bypassing the ATS, 3–1, 3–2
C
catalog number, 1–1
cleaning, 2–1
connections
power, 1–1
contact inspection, 3–4, 3–5
controller
disconnecting, 2–1
see Controller User’s Guide
381333–126
E
electrical operation, 1–4
Emergency Source Accepted light,
1–3
engine starting contacts, 1–2
F
foundation, 1–1
frequency, generator, 2–2
functional test, 1–2, 1–3, 1–4
H
harness, 1–2
disconnect plugs, 2–1
HELP
[e-mail]
800–800–ASCO
I
inspection, 3–1
installation, 1–1
interphase barriers, 3–4, 3–5
isolating the ATS, 3–3, 3–4
L
lifting device, transfer switch, 3–4
lights, 1–2, 1–3, 3–1, 3–2, 3–3
load connected to emergency, 1–3
load connected to normal, 1–3
lubrication, 2–1
M
maintenance, preventive, 2–1
maintenance handle, 2–2
warning, 2–2
manual load transfer, 2–2
warning, 2–2
N
nameplate, 1–1
Normal Source Accepted light, 1–3
O
operation
electrical, 1–4
manual, 2–2
warning, 2–2
P
parts, 2–1
phase rotation check, 1–3
preventive maintenance, 2–1
problem, 2–2
R
rating label, cover
replacement parts, 2–1
return to service, 3–5, 3–6, 3–7
S
service
ASCOServices,Inc.(ASI),2–1
settings
see Controller User’s Guide
381333–126
T
test, functional, 1–2, 1–3, 1–4
testing power cables, 1–1
time delays, 2–1
see Controller User’s Guide
381333–126
Transfer Control selector switch
Retransfer Delay Bypass, 1–3
Transfer Test, 1–3
Transfer Switch Connected To
Emergency light, 1–3
Transfer Switch Connected To
Normal light, 1–3
transfer test, 1–4, 2–1
transfer to emergency, 1–4, 2–1
transfer to normal, 1–4, 2–1
troubleshooting, 2–2
V
voltage checks, 1–3
voltage, pickup and dropout settings
see Controller User’s Guide
381333–126