Cutler-Hammer AMPGARD Series User manual

Effective 11/97
I.B. 48004
Cutler-Hammer
Instructions for 26" Wide Vacuum-Break Starters
Rated 360 Amperes, 7200 Volts, Stab-Connected
Fig. 1 Ampgard® Motor Controller, 26" Wide
DANGER
HAZARDOUS VOLTAGE.
READ AND UNDERSTAND THIS MANUAL IN ITS
ENTIRETY BEFORE INSTALLING OR OPERATING
CONTROLLER. INSTALLATION, ADJUSTMENT, REPAIR
AND MAINTENANCE OF THESE CONTROLLERS MUST
BE PERFORMED BY QUALIFIED PERSONNEL. A
QUALIFIED PERSON IS ONE WHO IS FAMILIAR WITH
THE CONSTRUCTION AND OPERATION OF THIS
EQUIPMENT AND THE HAZARDS INVOLVED.
THE CONTROLLER
Each Ampgard®motor starter (controller) consists of one
nonload-break isolating switch, one Type SJD, NEMA
Size H3, vacuum-break contactor, current-limiting fuses,
a set of current transformers, and some form of overload
protection. The isolating switch has a limited make and
break rating, suitable only for closing and opening limited
magnetizing current loads. The controller is designed to
start, stop and protect a three-phase medium-voltage
motor within the ratings shown in Table I. The controller
may also be used to switch transformer windings or
capacitor banks. Each Ampgard®controller occupies all
of a steel structure that may also enclose a horizontal
bus system to distribute power to two or more sections
and a vertical bus system in each section connected to
the horizontal main bus system. They are configured for
full-voltage starting, nonreversing, single-speed applica-
tions.
TABLE I. AMPGARD®EQUIPMENT RATINGS
Continuous 50 or 60 Hertz Interrupting Capacity, 50-60 Hz Isolating
Range Of Normal Current Horsepower Rating (rms) Symmetrical At Switch
System Utilization Rating Synchronous Motor Induction Nominal Utilization Voltage Make/Break
Voltage Voltage Enclosed 80% P.F. 100% P.F. Motor Fuses Controller Ratings
2200-2500 2300 360A 1500 1750 1500 50,000 Amp 200,000 kVA 750 VA
3800-5000 4000 360A 2500 3000 2500 50,000 Amp 350,000 kVA 600 VA
6200-7200 6600 360A 4000 5000 4000 50,000 Amp 570,000 kVA 600 VA
Nonmotor Applications at: >>>>>>>>> 2200 - 2500 Volts 3800 - 5000 Volts 6200 - 7200 Volts
Transformer Switching Rating = 1250 kVA 2250 kVA 3000 kVA
Capacitor Switching Rating = 1200 kVAR 2100 kVAR 2400 kVAR

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MEDIUM-VOLTAGE COMPONENTS
The flow of power through a vacuum-break controller
(starter) can be traced by referring to the lower portion of
Figure 5, where the controller is shown in the energized
position. The line stab assembly mounted at the back of
the enclosure also serves as the controller line terminals
(1). The stabs themselves are engaged by the fuse jaws
(2) of the isolating switch which is mounted on rails at the
top of the lower compartment. The line ferrules (3) of the
current-limiting motor-starting power circuit fuses (4) clip
into the fuse jaws, and the load ferrules (5) fit into the
fuse holders (6) which are part of the contactor line
terminals. Power flow through the contactor is from the
load ferrules of the power circuit fuses, through the
shunts (7), and the vacuum interrupters (bottles) of the
contactor (8), to the contactor load terminals. Spring-
loaded contact jaws (9) mounted on the contactor load
terminals plug onto the lower stab assembly (10), provid-
ing a convenient means to disconnect the contactor.
Cables (11) pass through current transformers and
connect the load stabs to the controller load (motor)
terminals mounted on a pan behind the low-voltage panel
which is behind the door above the isolating switch. See
Figures 2 and 4. Connect the conductors from the motor
to these latter terminals. Do not disassemble the factory
installed cables that run from the contactor load stabs,
through the current transformers to the controller load
(motor) terminals.
LOW-VOLTAGE CONTROL COMPONENTS
The low-voltage components consisting of an interposing
relay, protective relays, and optional equipment are
mounted on a hinged panel behind the upper door. The
Fig. 3 SJD Contactor & Isolating Switch
Fig. 4 Load Terminal Compartment
Fig. 2 Low-Voltage Compartment
single-phase control power transformer is bolted to the
contactor frame.The capacity of this transformer ranges
from 600VA to 2 kVA, depending upon voltage, frequency
and extra capacity requirements. The primary of the
control power transformer is connected to the line
through the power circuit fuse assembly, and is protected
by two additional low rating current-limiting fuses
mounted on the contactor. See Figure 5. The secondary
of the control power transformer supplies power to the
120 (or 240) volt grounded control circuit through second-
ary fuses mounted next to the test-run plug.

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Fig. 5 Ampgard
®
Components

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LOW-VOLTAGE CONTROL COMPONENTS (Cont.)
Pull-apart terminal blocks are mounted on the pan
directly in front of the low-voltage panel. These terminal
blocks permit mechanical and electrical separation of the
contactor from the structure for servicing or replacement.
Those Ampgard®motor controllers that include metering
have instrument-grade potential transformers bolted to
the contactor frame, opposite the control power trans-
former.
To energize the primary of the control power transformer,
the contactor must be inserted into the enclosure, the
power circuit fuses must be installed, and the isolating
switch must be closed.
For convenience during maintenance, when it may be
desirable to energize the contactor or the control circuit, a
test-run plug is provided. WITH THE ISOLATING
SWITCH OPEN, disconnect the plug from the socket and
plug it into a 120-volt single phase polarized extension
cord (or 240-volt when specified). See Figure 7.
Disconnect this temporary circuit and restore the plug to
its socket on the contactor before returning unit to service.
LOW-VOLTAGE CUTOFF SWITCH
Two auxiliary switches are installed behind the operating
handle housing of the isolating switch and used to
disconnect the load of a control power transformer, space
heaters, or other auxiliary circuits. Each of these auxil-
iary switches has an inductive load rating of 20 amperes
at not greater than 250 VAC. These auxiliary contacts
operate within the first five degrees of movement of the
isolating switch handle. At least one of the normally-open
contacts of these switches disconnects the control power
transformer from its load.
ISOLATING SWITCH
Each Ampgard®isolating switch is a medium-voltage,
three-pole, manually operated device. It consists of an
operating mechanism and a sliding tray mounted be-
tween two steel end plates. The sliding tray is molded
insulating material and carries three sets of fuse jaw
finger assemblies. One end of the fuse jaw finger assem-
bly grips the upper ferrule of the power fuse while the
other end engages the line stab. In the switch open
position, the three fuse jaw fingers are grounded.
Arc-resistant and flame-retarding insulating barriers are
mounted between phases and also between the two outside
poles and the isolating switch end plates. This isolating
switch is a nonload-break device. It must never close or
interrupt a power load. However, it does have a limited
capacity for interrupting the single-phase control power and
potential transformers exciting current. In terms of trans-
former ratings, the maximum load is the equivalent of an
unloaded (exciting current only) 6 kVAtransformer.
An Ampgard®starter is shipped with the isolating switch
in the ON position (Figure 6, ViewA). The isolating
switch handle is operated by moving it through a vertical
arc from the ON to the OFF position. From the OFF
position, it can be rotated 90ocounterclockwise to the
HORIZONTAL position, the door-open position (Figure 6,
View D).
In both the ON and OFF positions, a portion of the
handle housing extends over the door to the medium-
voltage compartment, preventing this door from being
opened. To open this door, the handle must be moved to
the HORIZONTAL position.
With the handle in the OFF position, up to three padlocks
can be used to lock out the switch, preventing the handle
from being moved to either the ON or the HORIZONTAL
position. This locked position prevents both unauthorized
entry into the medium-voltage compartment and acciden-
tal closing of the isolating switch while maintenance work
is being done. From the HORIZONTAL position, the
handle cannot be moved to the ON position without first
moving to the OFF position.
AB
CD
The operating handle has three distinct positions.
In the ON position (A), the isolating switch is closed, the door
is interlocked shut, and the starter may be energized.
In the OFF position (B), the isolating switch is open, the door
is interlocked shut, and the starter is de-energized and
grounded.
With the handle rotated 90° counterclockwise (C) to the
HORIZONTAL position (D), the isolating switch is open, the
starter is de-energized and grounded, and the door may be
opened.
Four Screws
▼
▼
▼
▼
Fig. 6 Isolating Switch Handle Positions

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SHORT-CIRCUIT AND OVERLOAD PROTECTION
Overcurrent protection is provided by the current-limiting
power circuit fuses and by the overload sensor supplied
from the current transformers. The power circuit fuses
have a special time/current characteristic for motor
service that is coordinated with the characteristic of the
overload protection. Currents greater than full-load motor
current, up through locked-rotor current, will operate the
overload protection and trip the contactor before the
fuses open. This coordination prevents unnecessary fuse
blowing. Since the interrupting capacity of the contactor
is limited, the power circuit fuses must operate faster
than the overload protector and contactor when the
overcurrent is greater than the current corresponding to
the contactor interrupting rating, in order to limit damage
to the starter or motor. In all faults above this interrupting
rating and within the rating of the equipment, the current-
limiting “R” rated fuses will operate first. The interrupting
rating of the vacuum bottles in this contactor is 7600
amperes, r.m.s. symetrical. The current transformers,
overload protector, and power circuit fuses are coordi-
nated with the motor characteristics, so that the controller
must be used with the motor for which it was designed.
Motors with special characteristics often require addi-
tional protective relays. Consult the instruction leaflet for
that particular protective relay before attempting any
adjustment or service. Protective relays are not set at
the factory.
ENCLOSURE
These Ampgard® motor controllers are supplied in cells
assembled into floor-mounted enclosures. These enclo-
sures are 26 inches wide x 30 inches deep x 90 inches
high (66 cm wide, 76 cm deep, and 229 cm high). Each
90-inch high enclosure accommodates one Ampgard®
starter. A 10-inch (25 cm) high horizontal bus enclosure
can be added at the top which increases the total enclo-
sure height to 100 inches (254 cm).
Fig. 7 Type SJD Contactor, Front View
POWER CIRCUIT
FUSE CLIP
(CPT) PRIMARY
FUSES
KICKOUT SPRING
CONTROLPOWER
TRANSFORMER
(CPT)
TEST-RUN PLUG
PULL-APART TERMINALBLOCKS TO
LOW-VOLTAGECOMPARTMENT
BARRIERS
PULL-APART TERMINAL
BLOCKS FROM ISOLATING
SWITCH
POTENTIAL
TRANSFORMER
POTENTIAL
TRANSFORMER
SECONDARY
FUSES
CPT
SECONDARY
FUSES

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MECHANICAL INTERLOCKS
Before putting an Ampgard®controller into service,
become familiar with the mechanical interlocks.
Door Interlock.
With the isolating switch handle in the HORIZONTAL
position, the door to the medium-voltage compartment can
be opened. As soon as the door opens, a mechanical
interlock becomes effective. It is designed to prevent the
user from accidentally operating the isolating switch handle
and closing the starter on to the line with the door open.
This interlock is a spring-loaded plunger located just
below the handle housing (Figure 6, View D). This
prevents the handle from being accidentally returned to
the OFF position. This interlock may be deliberately
bypassed by depressing the plunger with a screwdriver
so that the handle can be moved to the OFF position to
observe the operation of the isolating switch during
installation or maintenance. To do this, it is necessary to
deliberately bypass the interlock. The handle must be
returned to the HORIZONTAL position by again depress-
ing the interlock plunger before the door can be closed.
The operator must be aware of what he is doing and take
appropriate safety precautions.
Contactor-to-Isolating-Switch Interlock.
There is also a mechanical interlock that is designed to
prevent the isolating switch from closing with the
contactor already closed, and to prevent the contactor
from closing while the isolating switch is being opened.
This latter state (the transition phase) is shown in Figure
8. With the isolating switch fully open or fully closed the
contactor may be opened or closed. See Figure 9. If the
clevis is not connected to the interlock arm, the contactor
cannot be closed electrically. This is a positive interlock,
it cannot be bypassed without disassembly of the inter-
locking parts. DO NOT DISTURB THE FACTORY
ADJUSTMENTS OF THESE INTERLOCKS!
Line Stab Insulating Shutter.
When an Ampgard®isolating switch is installed, both a
shutter and a rear line stab barrier are in place in the
controller structure and are intended to prevent acciden-
tal access to the line bus. As the isolating switch is
opened, the sliding tray (Figure 10) mechanically drives
the insulating shutter closed across the three line stab
openings in the rear barrier. As the shutter closes the
openings, green and white striped labels are uncovered
to visually indicate that the shutter is closed. With the
isolating switch in the fully open position, the fuse jaw
finger assemblies and the line side of the main fuses are
connected to the ground bar.
Fig. 9 Contactor Open, Interlock Neutral
Fig. 8 Switch and Contactor Interlocked Closed

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As a final precaution before touching any of the electrical
parts of the starter, visually check to make certain that
the shutter is closed, the green and white striped labels
are visible, the grounding fingers are in contact with the
ground bar, and the tips of the fuse fingers are visible.
When the isolating switch is removed from the starter
structure, a latch lever (32, Figure 11) on the shutter
assembly is activated. It is designed to hold the insulating
shutter closed. This latch may be deliberately bypassed and
the shutter moved to the open position. BE CAREFUL!
Under these conditions the exposed line terminal stabs
of the starter may be energized at line potential.
When the isolating switch is replaced in the structure, the
latch member is automatically released to allow the
shutter to operate normally.
THE CONTACTOR
The Type SJD contactor has its main contacts sealed
inside ceramic tubes from which all air has been evacu-
ated, i.e., the contacts are in vacuum. No arc boxes are
required, because any arc formed between opening
contacts in a vacuum has no ionized air to sustain it. The
arc simply stops when the current goes through zero as it
alternates at line frequency. The arc usually does not
survive beyond the first half cycle after the contacts begin
to separate. The ceramic tube with the moving and
stationary contacts enclosed is called a vacuum inter-
rupter or a bottle, and there is one such bottle for each
pole of the contactor. A three-pole contactor has three
vacuum bottles. A metal bellows (like a small, circular
accordion) allows the moving contact to be closed and
pulled open from the outside without letting air into the
vacuum chamber of the bottle. Both the bellows and the
metal-to-ceramic seals of modern bottles have been
improved to the point that loss of vacuum is no longer
cause for undue concern. The moving contacts are
driven by a molded glass polyester crossbar (see Figure
12) rotating with a square steel shaft supported by two
shielded, pre-lubricated ball bearings that are clamped in
alignment for long life and free motion. Only the end
edges of the square shaft are rounded to fit the bearings,
so that portions of the four shaft flats provide positive
indexing of mechanical safety interlocks.
The contacts in an unmounted bottle (vacuum interrupter)
are normally-closed, because the outside air pressure
pushes against the flexible bellows. For contactor duty, the
contacts must be open when the operating magnet is not
energized. Therefore, the contacts of the vacuum bottles
must be held apart mechanically against the air pressure
when used in a contactor. In the Type SJD contactor, all of
the bottles are held open by a single kickout spring on the
front of the contactor. (See Figure 12.) The kickout spring
presses against the moving armature and crossbar and
thereby forces the bottles into the open contact position.
Note that in the open position, the crossbar is pulling the
moving contacts to hold them open.
Fig. 10 Sliding Tray Mechanism of 360Ampere Isolating
Switch Fig. 11 Shutter Operating Mechanism
AUXILIARY
CONTACTS

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THE CONTACTOR (Continued)
The kickout spring is adjustable and occupies the space
above the operating magnet. The kickout spring must be
removed before the magnet coil can be changed if that
becomes necessary. The normal position of the kickout
spring lever is vertical. The lever can be loosened to
unload the kickout spring (after loosening the set screw
that locks the adjusting screw). Unscrew the 0.313-inch
adjusting screw immediately below the kickout spring
itself. Although it can be loosened, the lever is captive.
As the screw is loosened, the kickout spring will reach its
relaxed, free length and can be removed easily. To re-
install it, reverse the procedure. Insert the
uncompressed, free spring into position; then apply load
by tightening the adjusting screw on the lever until the
lever is approximately vertical. See specific instructions
later. Because the spring forces exceed 100 pounds (45
kilograms), place a free hand over the kickout spring as a
precaution while turning the adjusting screw in either
direction. Tighten the set screw to lock the adjusting
screw.
The operating magnet (see Figure 12) is on the front of
the contactor. The coil has a “figure-eight” shape and is
really two coils in series, with a connection to their
common point. Both coils are encapsulated in one
environmentally-immune coil shell, which also contains a
full-wave silicon diode rectifier. An AC or DC source can
be connected to terminals A and B on the coil shell.
When an AC source is applied, the rectifier converts the
AC to unfiltered DC to excite the magnet. When a DC
source is applied, only two legs of the full-wave rectifier
are active and pass DC current for magnet excitation.
The magnet will not chatter as AC magnets sometimes
do but at less than rated voltage, it may hum slightly. A
normally-closed auxiliary contact, set to open slightly
before the armature fully closes, is connected to termi-
nals C and D on the coil shell. When adjusted correctly,
this auxiliary contact allows a relatively high current
through the pick-up winding, and as the contactor closes,
the auxiliary contact inserts the holding winding, which
reduces the coil current to a low value, sufficient to hold
the magnet closed without overheating.
In the description of the bottles, it was mentioned that no
arc boxes are required. However, because of electrical
clearance requirements, four phase barriers must be
installed before the contactor is energized.
CONTACTOR-MOUNTED COMPONENTS
To simplify installation and servicing, a number of related
components are mounted on the Type SJD contactor
chassis: a control power transformer with test plug and
fuses, instrument-quality potential transformers with
secondary fuses (when furnished), primary fuses for the
control power and potential transformers, and load side
fuse clips for the power circuit fuses. See Figures 7 and
13. The test-run plug is used to connect to an auxiliary
source of control voltage when it is not inserted into the
receptacle that is the output from the secondary of the
control power transformer. This male test plug can be
plugged into a standard polarized 120-volt (or 240-volt,
depending on coil voltage rating) extension cord socket
for testing the control circuit and any sequence without
energizing the medium-voltage controller at power circuit
voltage. When the male plug is transferred to the exten-
sion cord, it automatically disconnects from the control
power transformer to prevent feedback of high voltage
into the power circuits. Check to be sure no inadvertent
bypass of this arrangement has been made in the wiring
before relying on this safety feature.
CONTACTOR HANDLING
Each contactor weighs about 160 pounds (73 kilograms). An
oblong hole is provided in each sidesheet for lifting if desired.
A horizontal bar is provided at the front for pulling the
contactor out of its cell, or for pushing it back into place.
When a type SJD contactor is installed in a medium-
voltage controller it can be moved to a drawout position
or removed from the enclosure as follows:
DANGER
WARNING: ALL WORK ON THIS CONTACTOR SHOULD
BE DONE WITH THE MAIN DISCONNECT DEVICE
OPEN.AS WITHANY CONTACTOR OF THIS VOLTAGE,
THERE IS DANGER OF ELECTROCUTION AND/OR
SEVERE BURNS. MAKE CERTAIN THAT POWER IS
OFF. CHECK FOR THE PRESENCE OF DANGEROUS
VOLTAGE WITH AVOLTAGE SENSOROFTHE
APPROPRIATE RANGE.
1. If removal is planned, provide a lift truck or suitable
platform to receive the contactor as it comes out.
2. Make sure all circuits are deenergized.
3. Remove the three power circuit fuses using the fuse
puller supplied with the starter.
4. Disconnect the pull-apart terminal blocks connecting
the contactor to the low-voltage compartment and
stow them so that the cable will not be damaged.

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Fig. 12 Type SJD Contactor Positions
CONTACTOR
OPEN
CONTACTOR
CLOSED

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CONTACTOR HANDLING (Cont.)
5. Disconnect the isolating switch auxiliary contact pull-
apart terminal blocks located on the lower right-hand
side of the isolating switch.
6. Loosen the hex-head bolt attaching the clevis at the
end of the isolating switch interlock rod to the
contactor mechanical interlock sufficiently far to free
the clevis and rod. See Figures 8 and 9.
7. Use a 0.50-inch socket wrench to remove the horizon-
tally-mounted positioning bolt located at the bottom
front edge of the contactor right-hand sidesheet.
8. Carefully slide the contactor out to a balanced
drawout position or onto the fork truck or platform. All
routine inspection and maintenance can be done with
the contactor in the drawout position. Lift off the
phase barriers for easier access.
To reinstall, reverse the procedure.
INSTALLATION
This industrial type control is designed to be installed by
adequately trained and qualified personnel with appropri-
ate supervision. These instructions do not cover all
details, variations, or combinations of the equipment, its
storage, delivery, installation, check-out, safe operation,
or maintenance. Care must be exercised to comply with
local, state, and national regulations, as well as safety
practices, for this class of equipment. See START-UP
PRECAUTIONS.
For site preparation and general information regarding
receiving, storage, and installation see I.B. 48001.
CAUTION
The motor controller should be kept in an upright position
unless specific instructions to the contrary are provided
with the controller.
After a level installation site has been prepared, the
Ampgard®assemblies positioned and fastened in place,
and protective packaging removed, the individual control-
lers can be disassembled to permit access to conduit
and complete wiring. Step-by-step disassembly proce-
dures are shown on Pages 12, 13, and 14. Following the
recommended procedures will save time. All cable
connections can be made by access through the front of
the enclosure.
When there is access space behind the installation, the
rear panel of the enclosure can be removed to facilitate
wiring. Adequate space has been provided at the rear of
the enclosure for medium-voltage line and load cables,
while low-voltage cables may be conveniently arranged
near the right-hand enclosure wall. See Figure 15.
Fig. 13 Type SJD Contactor Rear View
TALL STRUCTURE — MAY TIP OVER IF MISHANDLED.
MAY CAUSE BODILY INJURY OR EQUIPMENT DAMAGE.
DO NOT REMOVE FROM SKID UNTIL READY TO SE-
CURE IN PLACE. READ THE HANDLING INSTRUC-
TIONS IN I.B. 48001 BEFORE MOVING.
Medium-voltage motor controllers are extremely heavy
and the moving equipment used in handling must be
capable of handling the weight of the motor controller.
Confirm this capability prior to starting any handling
operations with the controller.