Three-Phase Pad-Mounted Transformer Features
Howard Industries liquid-filled three-phase pad-mounted transformers are an
excellent choice for any commercial or industrial underground distribution system.
Typical applications include manufacturing facilities, refineries, office buildings,
schools, hospitals, restaurants, warehouses, and retail stores. All Howard Industries
transformers are designed, built, and tested in an ISO-9001 certified facility in
accordance with applicable industry standards.
Howard three-phase pad-mounted transformers are available in capacities from
30 to 10000 kVA, with high-voltage ratings from 2400 through 34500, and low-voltage
ratings from 208Y/120 through 8600. All designs feature fully enclosed tamper
resistant terminal compartments and can be supplied with dead-front or live-front
construction (Space-Saver 3TM style available with dead-front construction only), for
radial or loop feed applications.
A wide range of features and accessories is available to satisfy almost any special
requirement, including fuses, surge arresters, gauges, controls, cooling fans, pressure
relief devices, load-break switches, and high-voltage tap switches. In addition to the
standard mineral oil, alternate insulation fluids such as R-Temp, silicone, and seedbased vegetable oil are available for special applications.
Standard Features and Accessories
• Meets or exceeds current
ANSI, NEMA, and RUS
standards as applicable
(except for certain
dimensional characteristics of the Space-Saver
3TM design)
• Full compliance with
ANSI C57.12.28 enclosure integrity standards
• Externally clamped
universal high-voltage
bushing wells for dead
front applications (three
for radial feed operation
or six for loop feed
operation)
• Externally clamped lowvoltage bushings with
threaded stud for fullload current through
1400 Amps, or externally
clamped one-piece
NEMA spade bushings
for full-load current
above 1400 Amps
• Front panel accessory
mounting brackets
(dead-front construction
only)
• Removable neutral
ground strap in low-
voltage compartment (for
wye connected lowvoltage ratings only)
• Removable high-voltage
/low-voltage neutral
link, internally mounted
and accessible through
tamper-resistant hand
hole (Wye-Wye units
only)
• Lifting provisions
• Jacking/rolling
provisions (Compartmental style only)
• Removable terminal
compartment and bottom
sill, and removable doors
with stainless steel
hinges (Compartmental
style only)
• Removable hood with
stainless steel hinges, and
removable sill with
stainless steel fasteners
(Space-Saver 3TM only)
• Bolted hand hole on oil
compartment top with
tamper-resistant security
cover (Compartmental
style only)
• Three-point door
latching system with
recessed interlocking
pentahead security bolt,
and padlock provision
(Compartmental style
only)
• Recessed hood latching
system with captive
pentahead security bolt,
floating nut, and
interlocking padlock
provision (Space-Saver
3TM only)
• Tank ground provisions
• Mild steel tank and
terminal compartment
construction
• Mild steel high-voltage
/low-voltage compartment barrier (Compartmental style only)
• Insulated high-voltage/
low-voltage compartment barrier (SpaceSaver 3TM only)
• Domed top surfaces on
tank and terminal
compartment to prevent
water retention
• Recessed tank compartment bottom
• Electrostatically applied
powder paint finish with
olive-green polyurethane
top coat (Munsell 7GY
3.29/1.5) provides
excellent resistance to
chipping, fading,
abrasion, and corrosion
• Oil fill/oil level plug
• Automatic pressure relief
device mounted in
terminal compartment
• Oil drain valve with
sampling device
(Compartmental style
only)
• Electrical grade mineral
oil insulation fluid with
oxidation inhibitor
• Laser engraved anodized
aluminum nameplate
• Decal bushing
designations
Standard KVA and Voltage Ratings
Dead Front
Compartmental Style
KVA Ratings (65° Rise, ONAN)
45, 75, 112.5, 150, 225, 300, 500, 750, 1000,
1500, 2000, 2500, 3000, 3750, 5000, 7000,
7500, 10000
High-Voltage Ratings (Delta or Wye)
2400 through 34500 (through 150 kV BIL)
Low-Voltage Ratings (Delta or Wye)
120 through 8600 or 14400Y (through
110 kV BIL)
Space-Saver 3TM
KVA Ratings (65° Rise, ONAN)
30, 45, 75, 112.5, 150
High-Voltage Ratings (Delta or Wye)
2400 through 34500 (through 150 kV BIL)
Low-Voltage Ratings (Delta or Wye)
120 through 480 (through 30 kV BIL)
Live Front
Compartmental Style
KVA Ratings (65° Rise, ONAN)
45, 75, 112.5, 150, 225, 300, 500,
750, 1000, 1500, 2000, 2500, 3000,
3750, 5000, 7000, 7500, 10000
High-Voltage Ratings
(Delta or Wye)
2400 through 34500
(through 200 kV BIL)
Low-Voltage Ratings
(Delta or Wye)
120 through 8600 or 14400Y
(through 110 kV BIL)
(Note: Certain combinations of kVA, high-voltage, and low-voltage ratings may not be available. Contact your distributor
for availability of other kVA sizes,voltage ratings, features, accessories, and design standards not listed.)
Optional Features, Accessories, and Design Standards
As an Energy Star Partner,
Howard Industries has determined
that its optional “Energy Star
Compliant” transformers meet
the Energy Star guidelines for
energy efficiency.
Howard Industries is a charter
member of the Energy Star
Transformer Program.
• Loadbreak high-voltage
bushing inserts or
externally clamped
integral (one piece) highvoltage bushings for
dead-front applications
• Externally clamped
porcelain high-voltage
bushings with eyebolt
connectors for live-front
applications (not available
on Space-Saver 3TM)
• Low-voltage connectors,
including various screwon or slip-on types
• Insulated interphase
barriers (Compartmental
style, live-front
construction only)
• Lightning arrester
mounting provisions
(Compartmental style,
live-front construction
only)
• Externally operable nonloadbreak high-voltage
tap switch with one of the
following tap ranges: four
2.5% taps above normal;
or four 2.5% taps below
normal; or two 2.5% taps
above and two 2.5% taps
below normal; or taps at
13800/13200/12870/
12540 for transformers
with a nominal highvoltage rating of 14400
(may not be available in
combination with dual
high-voltage switch)
• Externally operable dual
high-voltage switch (may
not be available in
combination with highvoltage tap switch)
• Fault indicators or fault
indicator mounting
provisions only
• Internal expulsion fuses,
alone or in combination
with internal backup
current limiting fuses
• Draw-out expulsion fuses
with isolation links, alone
or in combination with
internal backup current
limiting fuses
• Draw-out full-range
current limiting fuses in
dry-well canisters; with or
without interlocking
loadbreak switch
(Compartmental style
only)
• Internal full-range current
limiting fuses (Compartmental style only)
• Arc Strangler® fused
disconnect switches
(Compartmental style,
live-front construction
only)
• MOV surge arresters,
including under-oil,
elbow, or panel-mounted
types (panel-mounted
types are available on
compartmental live-front
units only)
• Drip shields for use with
draw-out expulsion fuses
• Externally operable twoposition or four-position
high-voltage loadbreak
switch
• Internal low-voltage
circuit breaker with
external operating handle,
or external molded case
low-voltage circuit
breakers (Compartmental
style only)
• High capacity pressure
relief device mounted on
tank cover (Compartmental style only)
• Drain valve with
sampling device
• Total stainless steel or
hybrid (mild steel/
stainless steel)
construction
• Temporary access service
provision (conduit hole)
• Hexhead security bolt
(pentahead standard)
• External Watt-hour meter
base with or without
meter, or mounting
provisions
only(Compartmental
style, live-front
construction only)
• External potential
transformers
• External current
transformers
• Tank ground connectors
• Cover mounted throat for
bus duct connection
(Compartmental style
only)
• Dial type temperature
gauge
• Dial type liquid level
gauge
• Dial type pressure/
vacuum gauge
• Cooling fans or fan
mounting provisions only
(Compartmental style
only)
• R-Temp, silicone or seedbased vegetable oil
insulation fluid
• Laser engraved stainless
steel nameplate
(aluminum standard)
• Custom stenciling or
labeling
• NEMA safety labels
• Energy efficient
amorphous metal cores
(available through 750
kVA only)
• Compliance with
Canadian Standards
Association (CSA)
standards or other nonU.S. standards
(Note: Contact your distributor or factory representative for availability of other kVA sizes, voltage
ratings, features, accessories and design standards not listed.)
Arc Strangler® is a registered trademark of Cooper Power Systems.
Howard Industries Distribution Transformers
are Available in a Complete Range of Types,
Sizes and Voltage Ratings.
Single-Phase
Pole-Mounted
Three-Phase
Pole-Mounted
Single-Phase
Pad-Mounted
Single-Phase
Subsurface
Available in capacities
ranging from 0.5 through
833 kVA. Voltage ratings
through 19.9/34.5 kV,
200 kV BIL.
Refer to Bulletin 1001
Available in capacities
ranging from 30 through
150 kVA. Voltage ratings
through 34.5/19.9 kV,
150 kV BIL.
Refer to Bulletin 1001
Available in capacities
ranging from 10 through
333 kVA. Voltage ratings
through 19.9/34.5 kV,
150 kV BIL.
Refer to Bulletin 1002
Available in capacities
ranging from 10 through
250 kVA. Voltage ratings
through 19.9/34.5 kV,
150 kV BIL.
Refer to Bulletin 1003
Three-Phase Substation
Three-Phase Pad-Mounted
Available in capacities ranging from 112.5 through
10,000 kVA. Voltage ratings through 69 kV, 350 kV BIL.
Refer to Bulletin 1004
Available in capacities ranging from 30 through 10,000
kVA. Voltage ratings through 34.5/19.9 kV, 200 kV BIL.
Refer to Bulletin 1005