Lake Shore 26220 Wiring diagram

Installation / Operation / Maintenance Manual 1 10/28/2019
INSTALLING, OPERATING AND MAINTAINING
AUTOMATIC TRANSFER SWITCHES
AS MANUFACTURED FOR
FLORIDA POWER & LIGHT
WITH ELECTROMECHANICAL CONTROLS
Lake Shore Electric Corporation
205 Willis Street
Bedford, OH 44146
Toll Free: 800-225-0141
Phone: [phone]
Fax: [phone]

DESCRIPTION
DRN:
STYLE 2 225A 2P 3Ø 4W 277/480V
-
FLORIDA POWER
BEDFORD, OHIO U.S.A.
AND LIGHT COMPANY
LAKE SHORE ELECTRIC
THIS DOCUMENT IS THE PROPERTY OF Lake Shore Electric Corporation. UNDER
COPYRIGHT LAW, DISTRIBUTION AND REPRODUCTION OF THIS DOCUMENT, IN WHOLE OR IN PART,
IS PROHIBITED WITHOUT PRIOR WRITTEN PERMISSION FROM Lake Shore Electric Corporation.
CUSTOMER:
PROJ:
-
-
SCALE: -
-
-
REV
-
-
- -
Corp
-
1
FPL220225C_-04
QUOTE/JOB#:
--
PG
DWG NUMBER
-- - CHK: -APV: -
OF 1
-
BY APV
-
-
-
-
- -
DATE
-
-
-

IS PROHIBITED WITHOUT PRIOR WRITTEN PERMISSION FROM Lake Shore Electric Corporation.
COPYRIGHT LAW, DISTRIBUTION AND REPRODUCTION OF THIS DOCUMENT, IN WHOLE OR IN PART,
THIS DOCUMENT IS THE PROPERTY OF Lake Shore Electric Corporation. UNDER
LAKE SHORE ELECTRIC
AND LIGHT COMPANY
BEDFORD, OHIO U.S.A.
FLORIDA POWER
-
STYLE 2 225A 3P 3Ø 4W 120/240V
DRN:
DESCRIPTION
PROJ:
CUSTOMER:
-
-
SCALE: -
REV
-
-
-
-
- -
Corp
FPL230225G_-03
1
-
QUOTE/JOB#:
--
PG
-
DWG NUMBER
- - CHK: -APV: -
OF 1
-
APVBY
-
-
-
-
- -
DATE
-
-
-

IS PROHIBITED WITHOUT PRIOR WRITTEN PERMISSION FROM Lake Shore Electric Corporation.
COPYRIGHT LAW, DISTRIBUTION AND REPRODUCTION OF THIS DOCUMENT, IN WHOLE OR IN PART,
THIS DOCUMENT IS THE PROPERTY OF Lake Shore Electric Corporation. UNDER
LAKE SHORE ELECTRIC
AND LIGHT COMPANY
BEDFORD, OHIO U.S.A.
FLORIDA POWER
277/480VAC 3P 3Ø 4W 400A
FPL230400CI ATS
DRN:
DESCRIPTION
PROJ:
CUSTOMER:
-
M&S NUMBER 0-283-408-090
SCALE: -
REV
-
-
-
-
- -
Corp
1X1-0XXX-03
1
--/--/--
QUOTE/JOB#:
--
PG
---
DWG NUMBER
--- --/--/-- CHK: --/--/-- APV: ---
OF 1
-
APVBY
-
-
-
-
- -
DATE
-
-
-

-
PG
IS PROHIBITED WITHOUT PRIOR WRITTEN PERMISSION FROM Lake Shore Electric Corporation.
COPYRIGHT LAW, DISTRIBUTION AND REPRODUCTION OF THIS DOCUMENT, IN WHOLE OR IN PART,
THIS DOCUMENT IS THE PROPERTY OF Lake Shore Electric Corporation. UNDER
LAKE SHORE ELECTRIC
APV
1=5
-
PROJ:
CUSTOMER:
SCALE:
AND LIGHT COMPANY
-
CHK:
BEDFORD, OHIO U.S.A.
--- --/--/--
FLORIDA POWER
-
STYLE 2 400A 3P 3Ø 4W 277/480
DRN: --
DWG NUMBER
APV:
DESCRIPTION
- -
REV
-
-
-
-
-
BY
-
-
Corp
1
OF
1
-
--
DATE
-
-
-
-
QUOTE/JOB#:
-
-
-
37.500
30.000
FPL230400G_-04 CH
31.500
39.000
Ø0.563
CURRENT
RATING STANDARD LUG OPTIONAL LUG
A) 400A: (1) 2/0-500MCM (1) 500-600MCM
OR (2) 2/0-250MCM
B) GROUND (1) #14-1/0
LUG/CONNECTION DATA:

---
1X1-0XXX-04
PG
IS PROHIBITED WITHOUT PRIOR WRITTEN PERMISSION FROM Lake Shore Electric Corporation.
COPYRIGHT LAW, DISTRIBUTION AND REPRODUCTION OF THIS DOCUMENT, IN WHOLE OR IN PART,
THIS DOCUMENT IS THE PROPERTY OF Lake Shore Electric Corporation. UNDER
LAKE SHORE ELECTRIC
APV
1=5
M&S NUMBER 0-283-408-090
PROJ:
CUSTOMER:
SCALE:
AND LIGHT COMPANY
-
CHK:
BEDFORD, OHIO U.S.A.
--/--/-----
FLORIDA POWER
277/480VAC 3P 3Ø 4W 400A
FPL230400CI ATS
DRN: --/--/-----
DWG NUMBER
APV:
DESCRIPTION
- -
REV
-
-
-
-
-
BY
-
-
Corp
1
OF
1
--/--/--
--
DATE
-
-
-
-
QUOTE/JOB#:
-
-
-
30.000
37.500

Installation / Operation / Maintenance Manual 10/28/2019
7
WARNING!
WHEN WORKING ON EQUIPMENT OF THIS TYPE, EXTREME DANGER OF
ELECTROCUTION EXISTS THAT MAY RESULT IN INJURY OR DEATH. DO NOT ATTEMPT
ANY REPAIRS OR ADJUSTMENTS TO THIS EQUIPMENT WITHOUT FIRST TAKING THE
APPROPRIATE PRECAUTIONS TO PREVENT PERSONAL INJURY AND EQUIPMENT
DAMAGE.
DURING INSTALLATION AND USE OF THIS PRODUCT, COMPLY WITH THE NATIONAL
ELECTRICAL CODE (NEC), FEDERAL, STATE AND LOCAL CODES, AND ALL OTHER
APPLICABLE SAFETY CODES.
MAIN UTILITY / EMERGENCY POWER MUST BE OFF DURING INSTALLATION, WHEN
PERFORMING EQUIPMENT MAINTENANCE OUTSIDE THE EQUIPMENTS NORMAL
MAINTENANCE SCOPE AND WHEN PERFORMING REQUIRED MAINTENANCE ON ANY
POWER CABLE(S) CONNECTED TO THE EQUIPMENT. TAKE ANY OTHER PRECAUTIONS
DETERMINED TO PREVENT PERSONAL INJURY AND EQUIPMENT DAMAGE.

Installation / Operation / Maintenance Manual 10/28/2019
8
WARRANTY
Lake Shore Electric Automatic Transfer Switches are guaranteed against defective materials and
workmanship for a period of one year from date of shipment. If, within one year after shipment, it is
proved to Lake Shore's satisfaction that the equipment requires valid warranty work and Lake Shore is
promptly notified of same, Lake Shore will make necessary corrections, free of charge. F.O.B. works
where manufactured.
Such necessary corrections constitute the full extent of Lake Shore's warranty. There are no warranties,
which extend beyond those described herein. This warranty is exclusive and is in lieu of all other
warranties, whether written, oral, implied or statutory. No warranty of merchantability or of fitness for
purpose shall apply.
Lake Shore is not responsible for damage to its equipment through improper installation or use,
unauthorized repair or modifications, or attempts to operate it above its rated capacities or in abnormal
environments. In no event, whether as a failure to meet conditions of the warranty or otherwise, shall
Lake Shore be liable for any special, incidental, or consequential damages, including, but not limited
to, loss of profit or revenues, loss of good will, damages to associated equipment, cost of capital, cost
of substitute products, facilities, service or replacement power, costs of downtime or claims of third
parties for such damages.
Notice: The owner of this automatic transfer switch must perform certain required
maintenance functions as described in APPENDIX A, APPENDIX B, and
APPENDIX C of this manual in order to maintain Lake Shore's one year exclusive
warranty. Failure to perform this maintenance shall void the warranty.

Installation / Operation / Maintenance Manual 10/28/2019
9
TableofContents
1. CONSTRUCTION .............................................................................................................................................................................. 11
2. DESCRIPTION OF OPERATION.................................................................................................................................................. 11
3. INSTALLATION ................................................................................................................................................................................ 12
3.1. MOUNTING AND CONNECTING ........................................................................................................................................... 12
3.2. PLACING THE TRANSFER SWITCH IN OPERATION .................................................................................................... 12
4. OPERATING MECHANISM ........................................................................................................................................................... 14
4.1. GENERAL INFORMATION....................................................................................................................................................... 14
4.2. OPERATION .................................................................................................................................................................................. 14
4.3. REQUIRED MAINTENANCE ................................................................................................................................................... 14
4.4. MOTOR ASSEMBLY ................................................................................................................................................................... 14
5. MOLDED CASE SWITCHES .......................................................................................................................................................... 16
5.1. GENERAL INFORMATION....................................................................................................................................................... 16
5.2. INSPECTION AND MAINTENANCE ..................................................................................................................................... 16
6. TIMING RELAYS .............................................................................................................................................................................. 17
7. VOLTAGE RELAYS .......................................................................................................................................................................... 17
7.1. VOLTAGE SENSING – CLOSE DIFFERENTIAL ................................................................................................................ 17
8. TROUBLESHOOTING GUIDE ...................................................................................................................................................... 19
9. APPENDIXES ..................................................................................................................................................................................... 22
9.1. APPENDIX A ................................................................................................................................................................................. 22
9.2. APPENDIX B ................................................................................................................................................................................. 23
9.3. APPENDIX C ................................................................................................................................................................................. 24
9.4. CLOSE DIFFERENTIAL UNDERVOLTAGE PROTECTION ........................................................................................... 26
NOTE
Engineering changes may have been made after publication date. Any departure from this manual
should be checked with Lake Shore Electric Corporation.
Lake Shore Electric Corporation reserves the right to change specifications without prior notice.

Installation / Operation / Maintenance Manual 10/28/2019
10
PAGE INTENTIONALLY LEFT BLANK

Installation / Operation / Maintenance Manual 10/28/2019
11
1. CONSTRUCTION
All of the molded case switches and/or circuit breakers are electrically interlocked through control relays and auxiliary
switches, and mechanically interlocked through a walking beam mechanism which is located on the rear of the
baseplate. This mechanism is a fulcrum and lever device which positively prevents both molded case switches or circuit
breakers from being on the ON position simultaneously. It provides a “Fail-Safe” design.
The gear motors can operate on either AC or DC, and the gear reduction unit is permanently lubricated so that no
maintenance is required.
All transfer switches are provided with an insulated operating handle to enable personnel to manually operate the
transfer switch should this become necessary. The handle is permanently mounted and readily accessible in an
emergency.
All relays are of the industrial type to ensure long life and minimum maintenance. All relays are rated for continuous
duty to eliminate overheating of coils. The only relays that are continuously energized are the Phase Failure Relay
Normal (PFRN), Time Delay to Pickup (T) and the Normal Control Timer (TNR).
All timed control relays are of the pneumatic type.
Standard wiring harnesses are manufactured from 16-gauge insulated machine tool wire. All control circuits are
protected with fuses.
2. DESCRIPTION OF OPERATION
Normally, the transfer switch operates on the preferred power source with the Normal molded case switch in the closed
position and the Emergency molded case switch in the open position. (Refer to Wiring Diagrams, Pages 7, 9 and 11.
Note: These wiring diagrams are for reference only and should not be used in place of wiring diagrams are for
reference only and should not be used in place of wiring diagrams for a specific switch.)
All Phases of the preferred power source are continuously monitored by a voltage sensitive relay which is adjustable
from 70% to 90% of nominal. In the event of a drop in any phase of the preferred voltage below the drop-out set point
the voltage relay, the TNR Timer begins timing.
Upon completion of this ten second delay, the transfer switch motor is energized through the emergency relay and TNR
contact opening the Normal switch and closing the Emergency switch, thus affecting the power source transfer. With
the switch now operating on the emergency source, the voltage relay continues to monitor the preferred source.
When all phases of the preferred source return to the pickup level of the voltage relay, the “T” Timer begins timing,
upon completion of this 10 second delay, the transfer switch motor is energized through the “TNR” contact, opening the
Emergency Switch and closing the normal switch, thus affecting the power source transfer.

Installation / Operation / Maintenance Manual 10/28/2019
12
3. INSTALLATION
3.1. MOUNTING AND CONNECTING
The standard Lake Shore transfer switch is designed for operation in a clean, dry, dust-free location where a minimum
of vibration is present.
Enclosed type transfer switches are general designed for wall mounting; however, it is possible to adapt other
configurations. Open transfer switches are generally mounted in a switchboard; consequently, there are certain steps
which should be followed.
1. Allow adequate space for movement of movement of the manual operating handle.
2. Mount to a rigid framework to prevent vibration.
3. Review all Electrical clearances with the enclosure door or panels closed.
4. On rear connected switches, insure there is no strain on the studs due on improper alignment.
5. Lug sizes and arrangements may vary depending on molded case switch manufacturer.
6. Optional lug arrangements are available but must be specified at the time the transfer switch is ordered. Consult
Lake Shore Electric for details.
Before bringing the power cables within the enclosure, be certain that the lugs will be of adequate size. If not, larger lug
sizes may be ordered from Lake Shore Electric.
The preferred (normal)source power cable is connected to the Normal molded case switch at the terminals marked NL1,
NL2, and NL3 (refer to Wiring Diagrams, Pages 7, 9 and 11.)
The alternate (emergency) source power cable is connected in a like manner to the Emergency molded case switch
terminals marked EL1, EL2 and EL3. (Note: Be careful to pass the cable through any current transformers or other
devices which may be part of a generator control.) The load connections are made to the common bus at the terminals
marked L1, L2, and L3. On three-phase, four-wise transfer switches or single-phase, three-wire transfer switches, a
neutral bus is provided. NOTE: Verify that phase sequence rotation of normal and emergency sources are identical.
Failure to do this will result in damage to the transfer switch and other equipment and will void the warranty extended
by Lake Shore Electric Corporation.
A ground lug is provided on all transfer switches. This lug must be connected to the earth ground. When installing the
power cables, be careful not to disturb or damage the control wires that go to the various terminals.
CAUTION: Be sure to check that all power cable lugs are torqued to the applicable requirement for the switch (see
APPENDIX B).
Connect the contacts of the “P” Timer to the annunciator and supervisory controls. This contact closes to the
annunciator and opens to the supervisory control 10 seconds after either normal or emergency or both sources fail.
3.2. PLACING THE TRANSFER SWITCH IN OPERATION
Before energizing the switch electrically, be certain all external connections have been properly made according to the
wiring diagram provided with the switch. Inspect all wires, cables, and bus bar for abraded insulation, foreign matter,
and electrical clearance.
Manually set the transfer switch to the Normal source (Normal breaker CLOSED & Emergency breaker OPEN) and
energize the normal source. The “T” Timer will time out in 10 seconds and energize the TNR Timer which will allow
the transfer switch to stay on the preferred normal source.
If the T Timer or TNR Timer do not pick up, place a voltmeter on the normal source to be sure that the voltage is
adequate and within the range of the Phase Failure Relay (PFR). The switch will not operate on a voltage other than that
stamped on the nameplate of the transfer switch.

Installation / Operation / Maintenance Manual 10/28/2019
13
Do not attempt to energize the alternate (emergency) source until the switch is operating satisfactorily on normal. With
the normal source operating, the emergency source may now be manually energized for testing. The emergency source
including all safety interlocks should be checked over before an attempt is made at a complete automatic systems test.
When the emergency source has been tested satisfactorily and de-energized, a test of the automatic system can now be
tried.
All Lake Shore Electric Automatic Transfer Switches are furnished with a Load Test Switch. This switch may be
installed in the PFR or mounted separately on the panel. A test of the automatic circuitry can be initiated by moving this
load test switch to the test position. This will cause the normal control circuits to de-energize and give a signal to
transfer to the emergency position.
To test the full automatic operation of the transfer switch, make sure the transfer switch is operating on the normal
source. Place the load test switch in the test position. The transfer switch will transfer to the emergency source after a
10 second time delay.
After the emergency operation has been tested, return the load test switch to the normal position. This will cause the
transfer switch to return to the preferred (normal) source after the 10 seconds time delay of the T Timer.
The above test are sufficient to place the transfer switch in operation. The following paves contain specific information
on the various components and troubleshooting information.

Installation / Operation / Maintenance Manual 10/28/2019
14
4. OPERATING MECHANISM
4.1. GENERAL INFORMATION
The operating mechanism, pictured in Figure 1 (page 15). The motor (4) is a universal type, reversible motor and is
shipped as a complete component including the gearbox. The gearbox is a sealed unit, which should never require
maintenance or attention. Because of the wide range of molded case switches used on Lake Shore Electric Transfer
Switches, if motor replacement is necessary, please specify the serial number and model number of the transfer switch.
4.2. OPERATION
When a signal to transfer is received through the normally-closed contacts of the auxiliary switch, the motor is energized
and the gear box turns the drive drum (8) which sets up a friction pull between itself and the drive shoe lining (13). This
friction pull is sufficient to pull the drive arms (2) over to the new position, actuating the switch handle. As soon as the
dive arms have reached their new position, the auxiliary switch changes position cuttings off the motor while at the
same time setting up the circuit for the next transfer in the opposite direction. Because of the built-in features of the
friction drive, it is possible to manually operate the switch by moving the manual handle (1) without engaging any
clutches or devices.
4.3. REQUIRED MAINTENANCE
Please refer to the APPENDIX A for required maintenance on the operating mechanism necessary to maintain your
exclusive one-year Lake Shore Electric Corporation warranty.
4.4. MOTOR ASSEMBLY
To assemble the operating mechanism, first place the drive drum keys (11) on each side of the shaft, which extends from
the gearbox. Next, slide the two drive drums (8) on the shafts. Insert one drive shoe pivot (10) into one drive arm (2)
from the bottom, followed by the drive shoe (12) and the drive shoe lining (13). Be sure that the lining fits snugly into
the drive shoe and that the concave cup end of the drive shoe pivot (10) engages the nipple on the drive shoe. Hold the
entire assembly together and slip it onto one shaft, pushing it all the way to the drive drum. Now the spring (9) and
adjustment screw (3) may be assembled into the drive arm (2) from the top. Repeat this procedure for the other drive
arm assembly, if present.
Place the lever arm support (17) in such a way that it straddles the gearbox and engages the drive arm assemblies on
both sides of the gearbox. Tighten the mounting screws and assemble the lever arm across the two molded case
switches by fastening the lever arm to the lever arm support with the manual handle assembly (1). Observe the molded
case switch-actuating lever, as it is manually opens and closes the molded case switch, checking that it completely
transfers the molded case switches. The disassembly procedure of the mechanism is the reverse of the above.

Installation / Operation / Maintenance Manual 10/28/2019
15
Figure 1
LEGEND
1. Manual Handle
2. Drive Arms
3. Adjustment Screw
4. Motor
8. Drive Drums
9. Spring
10. Drive Shoe Pivot
11. Drive Drum Keys
12. Drive Shoe
13. Drive Shore Lining
17. Lever Arm
Mounting Bracket

Installation / Operation / Maintenance Manual 10/28/2019
16
5. MOLDED CASE SWITCHES
5.1. GENERAL INFORMATION
The molded case switches used in transfer switches are the standard devices supplied by molded case switch
manufactures. Figure 2 (page 16).
Thermal magnetic or magnetic trip units may be installed (Accessory 23) for thermal overload and short circuit
protection. When these trips are provided, a bell alarm contact is included inside the breaker to indicate to the transfer
switch circuit that the breaker has tripped due to an overload. This breaks the motor circuit and prevents the transfer
switch from cycling between the Normal and Emergency positions.
If either breaker trips due to overload, it can be reset by manually operating the transfer switch to a position so that the
breaker resets. After resetting, return the transfer switch to the proper position. A shunt trip may also be provided. This
allows the breaker to be electrically tripped from a remote location and can also be reset manually.
5.2. INSPECTION AND MAINTENANCE
Terminal lugs and trip units must be tight to prevent overheating. Due to the inherent wiping action built into the
moving contacts of all molded case switches, operating the switch several times under load will remove any high
resistance film that may have formed. Under normal conditions, additional cleaning of contacts is not required.
However, should operating and/or atmospheric conditions make it desirable to clean the contacts further, the following
procedure is recommended. (Refer to Figure 2).
Remove cover, arc chutes, and cable terminal assemblies. Wipe contact surfaces with a clean, lint free cloth. If surfaces
are excessively oxidized or corroded, scrape lightly with a fine file before wiping.
The auxiliary micro switches are mounted internally to the molded case switch.
Figure 2

Installation / Operation / Maintenance Manual 10/28/2019
17
6. TIMING RELAYS
The following Timing Relays are used on Lake Shore Automatic Transfer Switches.
Timing Relay Factory Setting Time of Delay Function .
T 10 Seconds On Delay Time Delay to Transfer to Normal
TNR 10 Seconds Off Delay Time Delay to Transfer to Emergency
P 10 Seconds Off Delay Time Delay to Alarm Circuit
TNR, P Relay
These relays are pneumatic. They are true OFF delay relay as no power is required for timing. When power is applied
to the relay coil the N.O. and N.C. contacts transfer. When power is removed from the relay coil the timing cycle starts.
After the timer has timed out the contacts will transfer to their original state.
7. VOLTAGE RELAYS
7.1. VOLTAGE SENSING – CLOSE DIFFERENTIAL
This relay continuously monitors the voltage of a three phase or a single-phase power source. When the voltage in each
phase attains a value equal to or greater than the "pick-up" setting, the output contacts change state and the L.E.D.
energizes. When the voltage of any phase falls below the "drop-out" setting, the output contacts revert to their de-
energized state and the "LED" turns off.
Pick-up and dropout values are adjustable from 70 to 100% of nominal voltage via two potentiometers that are
externally accessible.
FACTORY SETTING
Unless a customer or specifications require specific settings, the voltage Sensing Relay will be factory set to dropout at
80% and pick-up at 90% of nominal voltage.
LAKE SHORE ELECTRIC THREE PHASE STYLE
The Lake Shore voltage-sensing relay is field adjustable.
CALIBRATION:
1. Select proper voltage range.
2. Set pickup potentiometer full clockwise.
3. Set dropout potentiometer full counter-clockwise
4. Using a small screwdriver, turn the calibrate potentiometer fully clockwise.
5. Apply nominal input voltage to unit.
6. Slowly turn the calibration potentiometer counter-clockwise until the units picks up as indicated by the
"energized" light.
7. Set pickup and dropout potentiometers to desired settings.
8. Unit is ready for operation.
Note: Field adjustment can only be considered approximate if potentiometers are set using the scale on the front of the
unit. For an accurate setting of the pickup and dropout points, a variable voltage power supply must be used.

Installation / Operation / Maintenance Manual 10/28/2019
18
LAKE SHORE ELECTRIC SINGLE-PHASE STYLE
The single-phase voltage sensing relays are adjustable to 70 to 100% of the voltage range selected. Indication
of pickup or dropout can only be verified by attaching a continuity meter to the common and normally open
terminals. When the meter shows continuity, the PFR is picked up.
CALIBRATION:
1. Remove protective black plugs (if present).
2. Using a small slotted screwdriver, turn the dropout potentiometer fully counter-clockwise.
3. Using a small slotted screwdriver, turn the pickup potentiometer fully clockwise.
4. Apply required level of pickup voltage to the unit.
5. Turn the pickup potentiometer slowly counter-clockwise until the meter shows continuity.
6. Reduce the voltage to the required voltage dropout level.
7. Turn the dropout potentiometer slowly clockwise until the meter shows no continuity.
SUBSTITUTE SINGLE PHASE STYLE
The single-phase voltage sensing relays are adjustable to 0 to 80% of the voltage range selected. Indication of
pickup or dropout can only be verified by attaching a continuity meter to the common, pin 11, and normally
open, pin 14, terminals. When the meter shows continuity, the PFR is picked up.

Installation / Operation / Maintenance Manual 10/28/2019
19
8. TROUBLESHOOTING GUIDE
This guide is intended to assist an individual with a basic understanding of electrical circuitry to troubleshoot an
automatic transfer switch as manufactured by Lake Shore Electric Corporation. Any questions relating to the use of this
Manual should be referred to the Service Department of Lake Shore Electric Corporation, 205 Willis Street, Bedford,
Ohio 44146, Phone [phone], Fax [phone].
CAUTION: WHEN WORKING ON EQUIPMENT OF THIS TYPE, EXTREME DANGER FROM
ELECTRICAL HAZARDS EXITS. DO NOT ATTEMPT ANY REPAIRS OR ADJUSTMENTS TO THIS
EQUIPMENT WITHOUT TAKING EVERY PRECAUTION TO PREVENT AN ACCIDENT.
WARNING!
IN INSTALLATION AND USE OF THIS PRODUCT, COMPLY WITH THE NATIONAL ELECTRICAL CODE,
FEDERAL, STATE AND LOCAL CODES, AND ALL APPLICABLE SAFETY CODES. IN ADDITION, TURN
OFF POWER AND TAKE OTHER NECESSARY PRECAUTIONS TO PREVENT PERSONAL INJURY AND
EQUIPMENT DAMAGE.
WHEN WORKING ON EQUIPMENT OF THIS TYPE, EXTREME DANGER OF ELECTROCUTION EXISTS.
THIS MAY RESULT IN INJURY OR DEATH. DO NOT ATTEMPT ANY REPAIRS OR ADJUSTMENTS TO
THIS EQUIPMENT WITHOUT FIRST TAKING EVERY PRECAUTION TO PREVENT ACCIDENTAL INJURIES.
The following conditions MUST be met before attempting to troubleshoot a molded case transfer switch:
1. A wiring diagram for the switch must be available.
2. Normal and Emergency voltage and frequency must be available and within the correct operating
limits.
3. Control fuses must be in proper working order.
4. Control circuit voltage (if transformers are used) must be 110 to 125 volts.
5. Connections to the PFR must be correct and the relay must be adjusted to pick up on the voltage at
which the switch is operating. See voltage relay instructions on a Page 17.
6. All timers must be turned down or considerations given to them while the tests are being conducted.
7. If trip units are included in the switch, they must be reset if previously tripped due to an overload.
8. All electrical connections must be tight and in accordance with the wiring diagram.
9. All components must be free of obvious defects with the exception of normal usage.
10. The switch must be connected to a good earth ground.
When you are satisfied that all the above conditions are met, and all accessories are either working correctly or
eliminated, the problem will be confined to:
1. The control relays and timers
2. The molded case switches.
3. The adjustment of the operating mechanism.
4. The motor and micro switches.
The troubleshooting procedures outlined here are designed to test the control circuit and the operating mechanism of the
transfer switch. It is, therefore, necessary that all factors external to the transfer switch are correct, and that all accessory
devices which are not imperative to switch operation either operate satisfactorily or be bypassed and jumped out of the
circuit.
Many of the accessory devices described below may not exist in the transfer switch being examined. The proper wiring

Installation / Operation / Maintenance Manual 10/28/2019
20
diagrams should be on hand before beginning work on the switch. We recommend that the entire manual be read before
attempting to make any adjustment. Above all, CAUTION is recommended.
Many of the troubleshooting tests require a simulated failure of the normal source. This can be done with the Load Test
Switch.
I) AUTOMATIC TRANSFER SWITCH WILL NOT TRANSFER TO EMERGENCY
1) Improper Emergency Voltage
Using an appropriately set voltmeter, check the emergency voltage on terminals EL1 and EL2 and EL2
to EL3 and EL3 to EL1. If each set of readings indicate the emergency’s line to line voltage, continue
to Step 2. If the readings do not indicate proper line to line voltage, further checks are required on the
emergency source.
2) Blown Fuse on Emergency Source
Using an appropriately set voltmeter, check the output voltage on wires EA-1 to EB-1 and EB-1 to EC-
1 and EC-1 to EA-1. If each set of readings indicate the emergency line to line voltage, continue to
step 3. If the readings do not indicate line to line voltage, replace the defective fuse.
3) Defective Emergency Control Transformer ECT
Using an appropriately set voltmeter, measure the voltage from terminals X1 to X2 of the ECT. If this
voltage is 120 Volts nominal, check the ECT transformer and/or return to step 2.
4) Phase Failure Relay Not Functioning (PFR)
Using an appropriately set voltmeter, check the voltage on the phase failure relay terminal C to N.O. If
the voltage is 120 VAC nominal, the Phase Failure Relay Normal is defective and must be replaced. If
the voltage is zero, continue to step 5.
5) Defective ER Relay
Using an appropriately set voltmeter, measure the voltage from wire 19 to wire 25. If this voltage is
120 Vac nominal, continue to step 6. If not, replace the defective ER relay.
6) Defective TNR Relay
Using an appropriately set voltmeter, measure the voltage from wire 18 to wire 25. If this voltage is
120 Vac nominal, continue to step 7. If not, replace the defective TNR relay.
7) Emergency Microswitch (MSE) Defective
a. Using an appropriately set voltmeter, check the voltage at terminals 18 to 25. If the voltage is
120 Vac nominal, continue to Step b; if voltage is not 120 VAC nominal, return to Step 6.
b. Using an appropriately set voltmeter, check the voltage at terminals 17 to 25. If the voltage is
120 VAC nominal, continue to Step 8; if voltage is not 120 VAC nominal, replace the
defective microswitch.
8) Transfer Motor (TM) Defective
Using an appropriately set voltmeter, check the voltage at terminals 17 to 25. If the voltage is 120
VAC nominal, replace the motor gear box assembly; if voltage is not 120 VAC nominal, return to Step