GE Industrial Solutions ZBTSCTH User Manual
OPERATION AND MAINTENANCE MANUAL
ZBTSCTH SERIES POWER PANEL
100 - 4000 AMPS
46R-7000D
Rev 8/97
INTRODUCTION
Zenith Bypass-Isolation Closed Transition Transfer Switches provide
Zenith’s most comprehensive load power protection during standard
operation, maintenance and testing procedures.
Closed Transition Transfer Switches parallel two available sources of
power during test procedures to enable transfer without interrupting power
to the load (make-before-break). Paralleling of the two sources occurs
within a predefined window of synchronization and the initial source is then
disconnected. If the primary source falls below preset voltage limits and the
second source is available, the transfer switch defaults to open transition
(break-before-make) mode. In this mode, the transfer switch uses the
power from the available source to open the switch from the “dead source”
first, before closing the switch into the second source. When in the BypassIsolation mode, the switch acts as a manual transfer switch, enabling
testing, repair and even removal of the automatic transfer switch.
All Zenith transfer switches are designed for use on emergency or
standby systems, and are rated for total system or motor loads.
Transfer switches are UL Listed under Standard 1008 and CSA
Certified under Standard C22.2 No. 178.
This manual provides information on the installation, operation, and
maintenance of the switch. In addition, a complete information package is
supplied with each transfer switch which details the features and
accessories provided on that switch. The information package and the
instruction manual should be kept in a readily accessible location to
provide complete reference information on this critically important piece of
equipment.
TABLE OF CONTENTS
Section I INSTALLATION
1. Requirements
2. Equipment Inspection and Storage
3. Mounting
4. Power Connections
5. Control Connections
6. Final Equipment Inspection
7. Functional Test
Section II OPERATION AND FEATURES
1. Sequence Of Operation
2. Bypass-Isolation Switch Operation
3. Zenith Standard Package
4. Zenith Optional Accessories
Section III MAINTENANCE AND TESTING
1. Inspection and Cleaning
2. Servicing
3. Testing
4. Troubleshooting
5. Emergency Service Procedure/Extended Parallel Time
2
2
2
2
3
4
5
5
6
6
8
11
11
12
12
12
12
13
14
Section IV ADJUSTMENTS AND SETTINGS
1. Paralleling Relay Settings
2. Solid State Timers
3. Voltage/Frequency Sensor (VFSM)
4. Solid State Phase Relay (ARSM)
5. Paralleling Window Under-Overvoltage Sensing Relay
6. Electronic Time Switch Z2000-2A
Appendix A TYPICAL SCHEMATIC DIAGRAMS
1. 100-400 Amps
2. 600-3000 Amps
3. Alarm Circuit Schematic
4. Three-Phase Control Sensing Schematic
5. Bypass Control Circuit
Appendix B REPLACEMENT PARTS
1. Power Panel — 100-400 Amps
2. Power Panel — 600-1200 Amps
3. Power Panel — 1600-3000 Amps
4. Bypass Subpanel
5. Control Panel Layout and Parts List
6. Cabinet Door Pilot Devices
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17
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19
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20
21
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23
23
23
24
24
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31
SECTION I - INSTALLATION
!
!
!
DANGER
HAZARDOUS VOLTAGE
(Can Cause Severe Injury or Death)
Turn OFF all power before installation,
adjustment, or removal of transfer switch
or any of its components.
Each Zenith transfer switch is factory wired and
tested. A complete information package is
furnished with each switch which includes:
a. Sequence of operation.
b. Description and operation of all
accessories supplied.
c. Power panel connection diagram and
schematic.
d. Description and identification of all
customer field connections.
Installation of Zenith transfer switches includes:
a. Mounting the transfer switch cabinet.
b. Connection of all Normal, Emergency,
and Load cables or bus bars.
c. Connection of external control circuits
as required.
1. REQUIREMENTS
DANGER
Closed transition transfer switches typically
require momentary paralleling of utility and
generator sources. The customer should
obtain approval from their utility before using
a closed transition transfer switch.
Before installation, it is necessary to store the
transfer switch in a clean dry place, protected
from dirt and water. Provide ample air circulation
and heat, if necessary, to prevent condensation.
Storage Temperature:
-30 C to + 65 C (-22 F to +149 F)
Operating Temperature (Ambient):
-20 C to +75 C (-4 F to +167 F) [40-260 Amps]
-20 C to +40 C (-4 F to +104 F)[400-3000 Amps]
Humidity:
5% to 95% (non-condensing)
3. MOUNTING
Adequate lifting means must be used to mount
the transfer switch into place. The recommended
method for moving the transfer switch using the
lifting eyes and a spreader bar is illustrated in
Figure 1. Enough room should be allowed to
open the cabinet doors fully for inspection and
servicing of the switch per NEC and local codes.
Before drilling conduit entry holes or any
accessory mounting holes, cover and protect the
switch and control panel to prevent dirt and metal
fragments from entering the mechanical and
electrical components. Failure to do so may
result in damage and malfunction of the switch.
H
45°
SPREADER BAR
The following requirements must be met to use a
closed transition transfer switch:
a. Isochronous governor with a frequency
range of 60 ± 0.2 Hz.
b. Shunt trip breaker on the genset with
a response time not exceeding 50
milliseconds.
2. EQUIPMENT INSPECTION AND
STORAGE
Immediately inspect the transfer switch when
received to detect any damage which may have
occurred during transit. If damage is found or
suspected, file claims as soon as possible with
the carrier and notify the nearest Zenith
representative.
ZBTSCTH Operation and Maintenance Manual (46R-7000)2 Zenith Controls, Inc.
LIFTING EYES
CABINET
D
Figure 1
NOTICE
When lifting the switch using a spreader bar,
height H must be equal to half of distance D.
SECTION I - INSTALLATION (Continued)
4. POWER CONNECTIONS
Zenith transfer switches are supplied with UL
listed solderless screw type terminals as
standard for the Normal, Emergency, and Load
power connections. Table 1 lists the number and
sizes of the cable lugs supplied as standard for
each switch amp rating.
Connect the Normal, Emergency, and Load
conductors to the clearly marked terminals on
the transfer switch. Remove surface oxides from
cables by cleaning with a wire brush. Verify that
all connections are correct before tightening
the lugs. All cable lug connections must be
tightened to the proper torque values as shown
in Table 2.
Do not run cables or wiring behind frontconnected transfer switches.
In cases where the Normal, Emergency, and
Load connections are made to a rear connected
bus bar, a compression washer, flat washer, and
a minimum grade 5 bolt must be used and
torqued to the values in Table 3.
Screw Type Terminals for External Power Connections
Switch Size
(Amps)
100 1 #14 to 1/0 AWG 3 #14 to 1/0 AWG
150 1 #8 to 3/0 AWG 3 #6 AWG to 300 MCM
225 1 #6 AWG to 250 MCM 3 #6 AWG to 300 MCM
260 1 #6 AWG to 350 MCM 3 #6 AWG to 300 MCM
Normal, Emergency & Load Terminals Fully Rated Neutral Bar (When Required)
Cable Per Pole Range of Wire Sizes Number of Cables Number of Cables
400 1 #4 AWG to 600 MCM 4 #6 AWG to 300 MCM
600 2 #2 AWG to 600 MCM 8 #2 AWG to 600 MCM
800
1000
1200
1600
2000
3000
4000
Line and load terminals are located in
rear and arranged for bus bar
connection.
4 #2 AWG to 600 MCM 12 #2 AWG to 600 MCM
12 3/0 AWG to 750 MCM
Table 1
Tightening Torque for Lugs
Socket Size Torque
Across Flats Lb.-In. Lb.-Ft.
1/8 45 4
5/32 100 8
3/16 120 10
7/32 150 12
1/4 200 17
5/16 275 23
3/8 375 31
1/2 500 42
9/16 600 50
Tightening Torque for Bus Bars
Bolt Size Torque Bolt (Grade 5)
Lb.-In. Lb.-Ft.
1/4-20 72 6
5/16-18 132 11
3/8-16 300 25
1/2-13 720 60
Table 3
Table 2
ZBTSCTH Operation and Maintenance Manual (46R-7000)Zenith Controls, Inc. 3
SECTION I - INSTALLATION (Continued)
5. CONTROL CONNECTIONS
A complete information package is furnished with
each transfer switch including a complete
connection diagram and schematic which details
all necessary control circuit field connections.
The engine start control wires connect to the
terminals specified in the upper right corner of
the bypass cabinet. Terminals for field
connections to the A3 Emergency auxiliary
contacts and the A4 Normal auxiliary contacts
are also provided. These terminals are clearly
marked and appear on the left side of the ATS
power panel. Figure 2 below shows the location
of these terminals.
Make all other necessary external control
connections to the appropriate terminal blocks
located on the control panel. Insure that all
connections are tightened to the torque
specified in Table 4.
Control Wire Connections
Wire Size (AWG) Torque Lb.-In.
18-16 19
14-8 19
6-4 36
Table 4
Figure 2
ZBTSCTH Operation and Maintenance Manual (46R-7000)4 Zenith Controls, Inc.
SECTION I - INSTALLATION (Continued)
!
6. FINAL EQUIPMENT INSPECTION
Prior to energizing the transfer switch:
a. Remove any debris incurred due to
shipment or installation. DO NOT use a
blower since debris may become lodged in
the electrical and mechanical components
and cause damage. Use of a vacuum is
recommended.
b. Verify that all cabled connections are
correct and that phase rotation of both
sources match.
c. Check engine start connections and verify
the correct connection of all control wires.
d. Check settings of all timers and adjust as
necessary. Also adjust any optional
accessories as required. [See MX200
manual (50R-2000) for instructions on
timer and option adjustments.]
e. Check the integrity of power connections
by verifying actual lug torque values as
specified in this manual.
f. Make sure that all covers and barriers are
installed and properly fastened.
7. FUNCTIONAL TEST
pick up and the LED indicator will illuminate.
Check the phase to phase voltages at the
Emergency line terminals. Also, verify that the
phase rotation of the Emergency source is the
same as the phase rotation of the Normal
source.
After the sources have been verified, shut down
the engine generator, and put the starting control
in the automatic position. Complete the visual
inspection of the transfer switch, and close and
lock the cabinet door.
Initiate the electrical transfer test by activating
the test switch (TS). This de-energizes the
engine start relay. The transfer switch closes into
Emergency only after the sync-check relay
ensures the proper phase relationship of both
sources. After the transfer switch closes into
Emergency, the SE limit switch becomes
activated to de-energize the CCE relay and
energize the CCNO relay. This opens the
transfer switch out of Normal. When the transfer
switch has opened out of Normal, the SNO-2
limit switch activates to de-energize the CCNO
relay. The transfer switch has now closed into
Emergency power without interrupting the load.
The functional testing of the transfer switch
consists of electrical tests described in this
section. Before proceeding, refer to the
information package supplied with the transfer
switch. Read and understand all instructions and
review the operation of all accessories provided.
Before starting the operation test, check the
equipment rating nameplate on the transfer
switch to verify the correct system voltage. An
example of the equipment rating nameplate is
shown in Figure 3.
Figure 3
To begin the test, close the Normal source circuit
breaker. Phase relays B1, B2, and B3 will pick
up and the LED indicators will illuminate. Verify
the phase to phase voltages at the Normal line
terminals.
Next, close the Emergency source breaker and
start the engine generator. The VFSM relay will
ZBTSCTH Operation and Maintenance Manual (46R-7000)Zenith Controls, Inc. 5
Turning the TS to AUTO initiates re-transfer to
Normal. The transfer switch closes into Normal
only after the sync-check relay ensures the
proper phase relationship of both sources. After
the transfer switch closes into Normal, the SN
limit switch becomes activated (de-activated in
400 Amp units) to de-energize the CCN relay and
energize the CCEO relay; the transfer switch
opens out of Emergency. Then the SEO-2 limit
switch activates to de-energize the CCEO relay.
The transfer switch has now closed back into
Normal power without interrupting the load.
The transfer switch defaults to an open transition
transfer when the Normal source fails. Closed
transition transfer is not possible with one source
available. Open transition transfer for testing can
be selected via the transition mode selector
switch. (For a description of the Open Transition
sequence of operation, refer to Section II Operation and Features, page 6.)
A 24 VDC circuit is supplied to control the alarm
and warning indicators. To ensure continuous
power to this circuit, a constant 24 VDC can be
supplied by the customer from the engine start
battery.
NOTICE
A periodic test of the transfer switch under
load conditions is recommended to insure
proper operation.
SECTION II - OPERATION AND FEATURES
1. SEQUENCE OF OPERATION
Figure 4 is a typical schematic diagram of a
Zenith closed transition transfer switch. The
information supplied with the transfer switch
includes a schematic diagram and description of
operation of all accessories provided.
Transfer of the load to the Emergency source
begins automatically when any phase of the
Normal source falls below the preset dropout
point and this undervoltage failure condition is
detected by solid state phase relays B1, B2, B3.
The phase relays drop out, de-energizing the
Normal control relays CR & CR2, and engine
start timer P1 begins its timing cycle. The P1 time
delay is provided to override momentary outages
and to prevent nuisance starting of the engine
generator. If the Normal source voltage returns
above the phase relays’ pickup setting, the P1
timing cycle is reset to zero by re-energizing the
CR relay.
If the normal source voltage does not return
before the P1 time delay is completed, the P1
timer drops out and sends a starting signal to the
engine generator. An Emergency voltage and
frequency sensing relay (VFSM) monitors the
voltage and frequency of the Emergency source.
When both the voltage and the frequency of the
Emergency source reach the preset pickup
points, the VFSM relay initiates transfer to the
Emergency source and timer W begins it timing
cycle. The W timer provides an adjustable
transfer delay to the Emergency source as
required.
When the W time is completed, the Emergency
control relay RT energizes and picks up the
CCNO relay. The CNO solenoid is then
energized to open the transfer switch from
normal position to neutral position. The switch
remains in the neutral position for the duration of
the DW time delay. After the DW time delay is
completed, the CCE relay energizes the CE
solenoid to close the transfer switch into the
emergency source. The SE limit switch activates
to de-energize the CCE relay.
The sequence for retransfer to the Normal
source begins automatically when the voltage on
all phases of the Normal source reach the preset
pickup point and this condition is detected by the
solid state phase relays, B1, B2, B3.
When the Normal source restores and if the
transition mode selector switch is in CT (Closed
Transition), the transfer switch will return to the
Normal source in a make-before-break sequence
(this is described in the Testing section of this
manual).
If the transition mode selector switch is in OT
(Open Transition), the transfer switch will return
to the normal source in a break-before-make
sequence. When the Normal source restores, the
solid state phase relays, B1, B2, B3 pick up and
switching to the Normal source is initiated by
energizing timer T, beginning its timer cycle. The
T timer provides an adjustable delay to insure
that the Normal source has stabilized before
reconnection to the load. If the Normal source
fails before the T time delay completes, the
phase relays drop out and the T timing cycle is
reset to zero.
When the T time delay is completed, the Normal
control relay CR energizes and picks up the
power relay CCEO. This energizes the CEO
solenoid opening the transfer switch out of the
emergency source. The SEO-1 limit switch
activates to energize the DT time delay and
de-energize the CCEO relay. After the DT time
delay is completed, the CCN relay energizes the
CN solenoid to retransfer the switch into the
normal source. The SN limit switch activates to
de-energize the CCN relay. The SN limit switch
also energizes the engine over-run timer U and
begins its timing cycle. This timer provides a
period of time for the engine generator to run
without load and cool down before shutdown.
After the U time delay is completed, the P1 timer
isenergizedand the enginegeneratoris shutdown.
NOTES:
1. The transition mode selector switch on the
front door enables the user to operate the
unit in Open Transition mode, if so desired.
2. When in Closed Transition mode, if the
transfer switch does not open the first source
within 100 milliseconds, an alarm will sound,
the transfer switch will open the last source it
closed in to and will lock out the control
circuit from any transfer operation. After the
condition has been corrected the control
circuit should be reset by turning the Failed
to Open Lockout Reset switch to the right.
3. The controls will provide a signal to shunt trip
the generator breaker if the transfer switch
remains closed into both sources for more
than 325 ms. The load will then be fed by the
utility source. The maximum time that the
two sources would be parallel, under these
conditions, is less than 0.5 sec. Before
operating the closed transition transfer
switch the condition must be corrected and
the shunt trip reset. Refer to the procedure
for servicing the switch after shunt tripping
occurs. The shunt trip reset switch is
provided on the front door. Alarm and lights
on the front door provide indication of failure
conditions.
ZBTSCTH Operation and Maintenance Manual (46R-7000)6 Zenith Controls, Inc.
SECTION II - OPERATION AND FEATURES (Continued)
Figure 4
ZBTSCTH Operation and Maintenance Manual (46R-7000)Zenith Controls, Inc. 7
SECTION II - OPERATION AND FEATURES (Continued)
2. BYPASS-ISOLATION OPERATION - 100-400 AMP
a. Automatic
1) Manually operated bypass switch contacts (BN/BE) are
open and ATS is supplying load.
2) Disconnect Switch (DS) is in Auto.
b. To Bypass ATS
1) Open bottom cabinet door and turn DS to Inhibit.
2) Position Manual Bypass Handle (MBH) to same power
source as ATS.
c. To Test ATS
1) Bypass per above instructions.
2) Move ATS Location Handle (ALH) to Test location.
3) Turn DS to Auto.
4) Test Switch (TS) on bottom cabinet door will allow
electrical operation of ATS.
d. To Isolate ATS
1) Bypass per above instructions.
2) Move ALH to Isolate location.
e. To Remove ATS
1) Bypass and isolate per above instructions.
2) Move ALH to Release location.
3) Disconnect multipin plugs.
4) Lift ATS out of drawer.
f. To Reconnect ATS
1) Place ATS into drawer slots (front rollers first).
2) Turn DS to Inhibit.
3) Manually position ATS into same source as bypass switch.
4) Reconnect multipin plugs and external connections to ATS.
5) Push ATS inward to engage carriage.
6) Move ALH to Test location (as indicated by light).
7) Turn DS to Auto and use TS to electrically operate ATS.
8) Turn DS to Inhibit.
9) Move ALH to Auto location.
10)Turn DS to Auto and open bypass with MBH.
11) ATS is now fully automatic.
Notes:
1. DS in Inhibit will prevent ATS
electrical operation.
2. Do not use excessive force on
mechanical handles.
3. Figures depict Bypass Normal.
Sequence is the same for
Bypass Emergency.
4. When ATS is in Test or Isolate,
bypass switch is manual;
transfer switch to either
available source (indicated on
light panel).
5. To operate bypass switch when
ATS is in Test or Isolate,
position MBH to available
power source.
Legend:
1. BP - bypass switch
(indicated by contacts
BN/BE) is a three position
switch.
2. ATS -Automatic Transfer
Switch.
ZBTSCTH Operation and Maintenance Manual (46R-7000)8 Zenith Controls, Inc.
SECTION II - OPERATION AND FEATURES (Continued)
3. BYPASS-ISOLATION OPERATION - 600-1200 AMP
a. Automatic
1) Manually operated bypass switch contacts (BN/BE) are
open and ATS is supplying load.
2) Disconnect Switch (DS) is in Auto.
b. To Bypass ATS
1) Open bottom cabinet door and turn DS to Inhibit.
2) Turn Bypass Selector Switch (BSS) to same power source
as ATS.
3) Move the Manual Bypass Handle (MBH) upward.
c. To Test ATS
1) Bypass per above instructions.
2) Rotate crank mechanism counterclockwise until ATS Test
light is illuminated.
3) Turn DS to Auto.
4) Test Switch (TS) on bottom cabinet door will allow electrical
operation of ATS.
d. To Isolate ATS
1) Bypass per above instructions.
2) Rotate crank mechanism counterclockwise until ATS
Isolated light is illuminated.
e. To Remove ATS
1) Bypass and isolate per above instructions.
2) Disconnect multipin plugs and external connections to ATS.
3) Rotate four power panel latches to vertical position, slide
ATS forward and lock mechanism in place.
4) ATS can now be removed from cabinet.
f. To Reconnect ATS
1) Place ATS in slide mechanism.
2) Unlock slide mechanism. Slide ATS over power panel
latches and rotate latches to horizontal position.
3) Turn DS to Inhibit.
4) Manually position ATS into same source as bypass switch.
5) Reconnect multipin plugs and external connections to ATS.
6) Rotate crank mechanismclockwiseuntilATS Test light is
illuminated.
7) Turn DS to Auto and use TS to electrically operate ATS.
8) Turn DS to Inhibit.
9) Move ALH to Auto location.
10)Turn DS to Auto and open bypass with MBH.
11) ATS is now fully automatic.
Notes:
1. DS in Inhibit will prevent ATS
electrical operation.
2. Do not use excessive force on
mechanical handles.
3. Figures depict Bypass Normal.
Sequence is the same for
Bypass Emergency.
4. When ATS is in Test or Isolate,
bypass switch is manual transfer
switch to either available source
(indicated on light panel).
5. To operate bypass switch when
ATS is in Test or Isolate:
a) Move MBH downward (to open
open Bypass Contacts BN/BE).
b) Turn BSS to opposite power
source.
c) Move MBH upward to close
into selected power source.
Legend:
1. BP - Bypass Switch
(indicated by contacts
BN/BE) is a three posi
tion switch.
2. ATS - Automatic Transfer
Switch.
ZBTSCTH Operation and Maintenance Manual (46R-7000)Zenith Controls, Inc. 9
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