Acme's product offers a full line of applications, from commercial
general power distribution and high harmonic conditions to specific
industrial motor drive/factory automation systems, to low voltage
landscape lighting applications. All of Acme products are designed,
constructed and rated in to meet or exceed the standards established UL,
CSA CE, NEMA, ANSI and IEEE. Acme Electric Corporation was founded in
1917 in Cleveland, Ohio. Since that time, Acme has been a leader in
supplying power conversion equipment to the electrical and electronic
markets. Dry type distribution transformers have been a central part of
the Acme product line for over sixty years.
Three Phase Transformers must have 3 coils or windings connected in the
proper sequence in order to match the incoming power and therefore
transform the power company voltage to the level of voltage needed while
maintaining the proper phasing or polarity.
277/480 PRIMARY VOLTS-208/277 SECONDARY VOLTS-10,60Hz
1. Determine electrical load A. Voltage required by load. B. Amperes or KVA required by load. C. Frequency in Hz (cycles per second). D. Verify load is designed to operate on three phase.
All the above information is standard data normally obtained from
nameplates or instruction manuals.
2. Determine supply voltage
A. Voltage of supply (source). B. Frequency in Hz (cycles per second).
The frequency of the line supply and electrical load must be the same. A
phase transformer is selected which is designed to operate at this
having a primary (input) equal to the supply voltage and a secondary
equal to the voltage required by the load.
3. If the load nameplate expresses a rating in KVA, a transformer can be
directly selected from the charts. Choose from the group of transformers
with primary and secondary voltages matching that which you have
A. Select a transformer with a standard KVA capacity equal to or
greater than that needed to operate the load. B. Primary taps are available on most models to compensate for line
variations. C. When load ratings are given only in amperes, tables 3 and 4 or
formulas may be used to determine proper KVA size for the required
(1) To determine three phase KVA when volts and
amperes are known:
Three Phase KVA = Volts x Amps x 1.73
(2) To determine Amperes when KVA and volts are known:
Amps = 3 Phase KVA x 1000
Volts x 1.73
Three Phase Example
Question: Select a transformer to fulfill the following conditions.
Load is a three phase
induction motor, 25 horsepower @ 240 volts, 60 Hz and a heater load of 4
@ 240 volts single phase. The supply voltage is 480Y/277, three phase, 4
wire. Answer: Compute the KVA required. Motor—From table 4 the
current is 68 amps.
240 volts x 68 amps x 1.73 = 28.2 KVA
(The KVA can also be obtained from table 4).
Heater — 4 KVA
A three phase transformer must be selected so that any one phase is not
Each phase should have the additional 4 KVA rating required by the
heater even though
the heater will operate on one phase only. So, the transformer should
have a minimum
KVA rating of 28.2 + 4 + 4 + 4 or 40.2 KVA. Refer to the appropriate
A 480 delta primary—240 delta secondary transformer may be used on a 4
480Y/277 volt supply. The fourth wire (neutral) is not connected to the
To not overload the transformer, a 45 KVA transformer should be
selected. NOTE: Any two wires of the 240 volts, 3 phase developed by the
secondary of the
transformer may be used to supply the heater. Any 2 wires of a 3 phase
is single phase.
FULL LOAD CURRENTS IN AMPERES-
THREE PHASE CIRCUITS
FULL LOAD AMPERES
THREE PHASE A.C. MOTOR
When motor service factor is greater than 1, increase full
load amps proportionally. Example: If service factor is 1.15,
increase above amp values by 15%.
3 phase KVA= Volts x Amps x 1.73
NOTE: If motors are started more than once per hour, increase
minimum transformer KVA by 20%.
allows signal or power to be taken from one device and fed into
another without electrically connecting the two.
are devices that transfer electrical energy from one electric
circuit to another, without changing the frequency, by
are designed to meet certain performance specifications and size
requirement that you require. There is a wide range of custom
Buck Boost Transformers
is a ideal solution for changing line voltage by small amounts.
Often used to buck (lower), or boost (raise) the voltage from 208v
to 240v for lighting applications.
Pole Mounted Transformers
are mounted to poles for overhead electrical lines. Used in various applications.
Are available in single phase or three phase transformers.
Medium Voltage Transformers
are used with a medium range of voltages. They come in a full
range from liquid-filled, convention dry type as well as cast coil.
Pad Mounted Transformers
are a excellent choice for commercial and industrial such as
manufacturing facilities, refineries, office buildings, schools,
hospitals, restaurants, and retail stores. They come in various
sizes and can be used underground as well.
typically these voltage transformers are used in power transmission
applications. High voltage transformers are also used in microwave.
- With Acme Electric being in business
over 80 years, they have always believed in offering there customers superior service, quality and technical expertise in the
AMVECO Transformers -
AMVECO designs and manufactures toroids
transformers, current transformers, and auto transformers. Most
AMVECO products are custom designed utilizing their state-of-art proprietary
CAD programs. The AMVECO engineers can quickly generate designs in a
matter of hours, if needed.
Federal Pacific Transformers -
Federal Pacific is a division of Electro- Mechanical Corporation, a
privately held, American owned company founded in 1958. Federal
pacific offers dry-type transformers from .050 KVA through 10,000
KVA single and three phase, up to 34.5 KV, 150 KV BIL with UL
approval through 15 KV.
Marcus Transformer - Ever since they opened their doors for business a half a century ago,
they have been a leader in innovative transformer design. As a
family-owned company they are proud of the reputation they have
earned for making quality-built transformers that deliver
exceptional performance and savings.
Hammond Transformers - Hammond Manufacturing was founded in 1917 in Guelph, Ontario,
Canada. In the last 3 decades it has expanded to the US and the
international markets offering many types of power transformers.
- TEMCo Transformer, a family-owned business which has been
manufacturing and distributing electrical products since
1968. They focus on transformers that significantly
reduce power consumption over 30 percent compared to competitive
GE Transformers - GE has been a key player in the energy industry for
more than a century. Since the installation of
their first steam turbine in 1901. They have become
number one provider of high-technology power generation
and distribution equipment.
Jefferson Electric Transformers - Jefferson Electric has
been a pioneer and innovator of magnetic products since 1915.
Jefferson broad line of dry-type transformers are backed by quality
assurance systems so stringent that each and every unit gets
thoroughly tested before it goes out there door.
Distribution Transformers - Distribution
transformers are generally used in electrical power
distribution and transmission power. This class of transformer has
the highest power, or volt-ampere ratings. and the highest
continuous voltage rating.
Substation Transformers - Substation Transformers are large
devices which usually weigh tens of thousands of pounds. They are
filled with tens of thousands of gallons of heat transfer fluid.
Although they are typically 99.8% efficient in the transforming of
electricity from one voltage to another, processing hundreds of Mega
Volts-Amps of electricity force the liberation of hundreds of BTUs
Medical Grade Isolation Transformer -
Medical Grade Transformers generally refer to the transformers
used in medical devices as well as hospital, biomedical and patient
care equipment. There are a number of strict safety rules,
guidelines and laws governing the design, construction and the test
of these transformers.
Drive Isolation Transformer -
They are used to isolate a drive from a main power line to
prevent the transmission of harmonics that the drives produce back
into the power line. They stop drive harmonics from disrupting
computers and other sensitive equipment.
Toroidal Transformers -
Toroidal Transformers are more efficient than the cheaper laminated EI types of similar power level. Some of the advantages are smaller
size, lower weight, less mechanical hum, (making them superior in
audio amplifier), low-off-load loss.
Step-Up Transformers - A Step-Up Transformer is one whose
secondary voltage is greater than its primary voltage.
This kind of transformer "steps up" the voltage applied
to it. -
- A Step-Down Transformer is designed to reduce voltage from primary to
They can range from sizes from .05 KVA to 500 KVA
Isolation Transformers -
An Isolation Transformer is a device that transfers energy from
the alternating current (AC) supply to an electrical or electronic
load. It isolates the windings to prevent transmitting certain
types of harmonics.
Buck Boost Transformers - Buck Boost
Transformers make small adjustments to the incoming voltage. They
are often used to change voltage from 208v to 240v for lighting
applications. Major advantages of Buck boost transformers
include; low cost, compact size and light weight.
High Voltage Transformer - There are many different types of
voltage transformers. A High Voltage Transformer operates with high
voltages. Typically, these voltage transformers are used in power
transmission applications, where voltages are high enough to present
a safety hazard.
Medium Voltage Transformers -
A Medium Voltage Transformer can be connected directly to a primary
distribution circuit and generally has the most load diversity.
These voltage transformers have installation practices that are
generally in accordance with application recommendations from the
Institute of Electrical and Electronic Engineers (IEEE).
Low Voltage Transformers
- A Low Voltage Transformer is an electrical device that transforms
120 volts (line voltage) into 12 volts or 24 volts (low voltage).
Some uses for low voltage transformer are in landscaping lighting.
Single Phase Transformers - In electrical engineering, single-phase electric power refers to the
distribution of electric power using a system in which all the
voltages of the supply vary in unison. Single-phase distribution is
used when loads are mostly lighting and heating, with few large
Three Phase Transformers - Three
Phase Transformers must have 3 coils or windings connected in
the proper sequence in order to match the incoming power and
therefore transform the power company voltage to the level of
voltage needed while maintaining the proper phasing or polarity.
Custom Transformers -
Custom Transformers are designed for a certain performance
specifications and size requirements. The company works with
your engineering specification.
Industrial Control Transformers -
Industrial Control Transformers are used to convert the
available supply voltage to the required voltage to supply
industrial control circuits and motor control loads.
Pad Mounted Transformers - Pad
Mounted Transformers are usually single phase, or three phase, and
used where safety is a main concern. Typical applications;
restaurant, commercial building, shopping mall, institutional.
Pole Mounted Transformers -
Pole Mounted Transformers are used for distribution in areas
with overhead primary lines. Outside a typical house one can see one
of these devices mounted on the top of an electrical pole.
Oil Filled Transformers -
Oil Filled Transformers are transformers that use insulating oil as
insulating materials. The oil helps cool the transformer.
Because it also provides part of the electrical insulation between
internal live parts, transformer oil must remain stable at high
temperatures over an extended period.
Dry Type Transformers - Dry-Type
Transformers are available for voltages up through 34.5 kV
(although the most common upper limit is 15) and KVA ratings up
through 10,000 (with 5000 as the usual limit). Dry-type use air as a
coolant, lowering health and environmentally concerns.
Auto Transformers -
An Autotransformer is an electrical transformer with only one
winding. The winding has at least three electrical connection points
called taps. Autotransformers are frequently used in power
applications to interconnect systems operating at different voltage
classes, for example 138 kV to 66 kV for transmission. Another
application is in industry to adapt machinery built for 480 V
supplies to operate on the local 600 V supply.
Electrical Transformers are devices used to raise or lower the
voltage of alternating current. For instance, power is transported
over long distance in high voltage power lines and then transformers
lower the voltage so that the power can be used by a business or household.
An Isolating Transformer is a transformer, often with
symmetrical windings, which is used to decouple two circuits.
An Isolation transformer allows an AC signal or power to be taken
from one device and fed into another without electrically connecting
the two circuits. Isolation transformers block transmission of DC
signals from one circuit to the other, but allow AC signals to pass.
Power Lines - A Transmission Line is the material medium or structure that forms
all or part of a path from one place to another for directing the
transmission of energy, such as electromagneticor acoustic waves as well as electric power
transmission. Components of transmission lines include wires, coaxialcables, dielectric slabs, option fibers,electric power lines, and waveguides.
Transformer Voltage - The measure of the amount of force on a
unit charge because of the surrounding charge.
Transformer Frequency -
The transformer cannot change the frequency of the supply. If the
supply is 60 hertz, the output will also be 60 hertz.
Transformer K Factor - Some transformers are now being offered
with a k-factor rating. This measure the transformer's ability to
withstand the heating effects of non-sinusoidal harmonic currents
produced by much of today's electronic equipment and certain
Primary Voltage - The coil winding that is directly connected
to the input power.
Harmonic Cancellation -
Harmonic cancellation is performed with harmonic canceling
transformers also known as phase-shifting transformers. A harmonic
canceling transformer is a relatively new power quality product for
mitigating harmonic problems in electrical distribution systems.
This type of transformer has patented built-in electromagnetic
technology designed to remove high neutral current and the most
harmful harmonics from the 3rd through 21st.
Enclosed transformers come with a weatherproof standard set by
Epoxy Encapsulated -
A process in which a transformer or one of its components is
completely sealed with epoxy or a similar material. This process is
normally preferred when a unit might encounter harsh environmental
Voltage Regulators - A
Voltage Regulator is an electrical regulator designed to
automatically maintain a constant voltage level.
It may use an electromechanical mechanism, or passive or active
electronic components. Depending on the design, it may be used to
regulate one or more AC or DC voltages.
AC Line Reactor -
AC Line Reactors is a three phase transformer used in
conjunction with AC variable frequency and DC motor drive.
They are a bi-directional protective filtering device.
Line Power Conditioners -
Power or Line Conditioners regulate, filter, and suppress noise in
AC power for sensitive computer and other solid state equipment.
DC Power Supplies -
Conversion of one form of electrical power to another desired
form and voltage. This typically involves converting 120 or 240 volt
AC supplied by a utility company to a well-regulated
lower voltage DC for electronic devices.
Rotary Phase Converters -
Rotary Phase Converters are commonly used in home or small
commercial or industrial settings. Rotary phase converters convert
single-phase power into three-phase power. This is a very
cost-effective way to power three-phase electric motors and other
three phase equipment.
Frequency Converters -
A Frequency Changer or Frequency Converter is an
electronic device that converts alternating current (AC) of one
frequency to alternating current of another frequency.
Voltage Converters -
A Voltage Converter changes the voltage of an electrical power
source and is usually combined with other components to create a
Magnetic Motor Starters - Magnetic Motor Starters are
essentially heavy duty relays mounted in boxes, often equipped with
heater/thermal overloads matched to the motor they start.
Motor Starting Auto Transformers - An Auto
Transformer starter uses an auto transformer to reduce
the voltage applied to a motor during start. The auto transformer
may have a number of output taps and be set-up to provide a single
stage starter, or a multistage starter.