How Does Transformer Manufacturer Company Brand Affect Power Transformer Quality and Properties?
 

You are ready to buy a transformer and have all your specifications and it time to pick the manufacturer. This is a very daunting task especially to us that are novice in the business. We hope in the following that we can give you some guidelines.

What type of winding material do they use:

Copper and aluminum are used for transformer windings. These materials are available in a variety of grades and thicknesses, each with their own efficiency characteristic. Winding losses, or load losses, arise from the conducting material's inherent resistance to the flow of electrical current. Winding losses increase with the square of the transformer load. Efficiency gains can by achieved by using materials with lower resistively or greater diameter. For example, coils make with copper can have considerably lower load losses than those make with other materials. Data based on popular 45 kVA size shows $1000/ year savings. That is $10,000 saved over ten years.

What type of core materials and how it is wound:

Since the majority of transformer losses at low load levels are due to core inefficiencies, much of the research on reducing transformer losses has concentrated on building more efficient cores. Core losses result from cyclic changes in the magnetic state of iron and "eddy-current" losses caused by the flow of small currents in the iron. Core losses can be reduced by improving core material. A conventional transformer used stacked lamination core assembly. 90 degrees square corners contribute to high core losses. So look for companies that offer unique wound core construction that ensures that flow of magnetic flux is carried in direction of cold-rolled grain-oriented steel for minimal core losses.

Noise Factor

It is best to address noise level at the beginning stage. Before you specify your transformer you must consider if you have a noise problem. A humming is a inherent characteristic of transformers due to the vibration caused by alternating flux in the magnetic core. Sound levels will vary according to transformers due to the vibration caused by alternating flux in the magnetic core. Sound levels will vary in the size of the transformer. Attention to installation methods can help reduce any objectionable noise. When possible, locate the transformer in an area where the ambient will be equal or greater than the noise of the transformer sound level. Avoid locating units in corners. Make connections with flexible conduits and couplings to prevent transmitting vibration to other  equipment. Larger units should be installed on flexible mountings to isolate the transformer from the building structure.  For example, if a building is being build, then a little thought beforehand will make sure the transformers are not placed in small reverberant rooms next to a proposed board room, sleeping areas, study areas or other occupied areas where the normal sound level is low. The NEMA-ST-20 has set standards for audible sound levels make sure your transformer meets or are lower then the standards.

The list below can be used as a guild lines in choosing the manufacturer:

These guild lines are for dry type, enclosed and ventilated transformers:

1. Transformers should be UL listed for non-sinusoidal current loads of a specified K Factor (UL Standard 1561)CSA certified and labeled as such.
    
2. For sizes 15 KVA and larger, low voltage dry transformer will be ventilated type, incorporating a 220 degree C insulation system an designed not to exceed 150 degree C temperature rise about a 40 degree C ambient under full load conditions. Taps are provided on the primary side of the transformer. There will be 2, 2.5% taps above normal full capacity and 4, 2.5% taps below normal full capacity.
    
3. 115 degree C rise transformers should incorporate a 220 degree C insulation system and be designed not to exceed 80 degree C temperature rise above a 40 degree C ambient under full load conditions. The transformer should have the ability to carry a continuous 15% over load with exceeding a 150 degree C rise above ambient.
    
4. 80 degree C rise transformers should incorporate a 220 degree C insulation system and be designed not to exceed 80 degree C temperature rise above a 40 degree C ambient under full load conditions. The transformer should have the ability to carry a continuous 30% overload without exceeding a 150 degree C rise above ambient.
5. Transformers should incorporate an electrostatic shield for the attenuation of voltage spikes, fine noise, and transients.
    
6. Transformers should be designed to handle non-linear loads and the adverse effects of harmonics.
    
7.  Transformer coils should be wound with foil to minimize the heating effects caused by harmonic currents.
    
8. Transformers should be able to power non-linear loads with a K-Factor as high as 20.
    
9. Transformer should operate at audible sound levels below NEMA ST-20. Sound levels should not exceed the following: 30-50 KVA: 45 db - 51-150 KVA: 50 db - 151-300 KVA: 55 db - 301-500 KVA: 60 db.  Sounds levels are based on transformers with a K-Factor of 4 and a temperature rise of 150 degrees centigrade.
    
10. Enclosed, ventilated transformers should incorporate vibration dampening pad in their construction, located between the transformer core and coil assembly and the the transformer case. External vibration dampening pads should not be used on enclosed, ventilated designs as they tend to increase audible noise. Transformers 15 KVA and larger should be floor mounted on a concrete pad. All connections to the transformer should be made by means of flexible metallic conduit.
     
11.  Transformers should incorporate a neutral conductor sized at 2 times rated phase current. Transformer cases should be grounded per the National Electric Code.
     
12. Transformers should be 60 Hz, 480 or 600 volts delta primary, 208Y/120 volt secondary. KVA rating as indicated. Manufacturer should provide all necessary lugs for all transformers. Transformer enclosures should be type 2 and UL-3R listed with the addition of a weather shield. 
     
13. Complete shop drawing should be submitted for approval on all dry type transformers.
     
14.  Typical performance data should be submitted for approval on all transformers. Factory tests should be made in accordance with the latest revisions of ANSI Test Code C57.12.91 for Dry Type Transformers. Performance data should contain:

A. No load losses.
B. Full load losses.
C. Polarity  and phase rotation.
D. Impendence at reference temperature.
E. Efficiencies at 25, 75, 50 and 100% load.
F. Regulation at 100% and 80% power factor
G. Audible sound level.
H. Insulation class and rated temperature rise.
I. Dimensions and weight.
J. Applied potential test.
K.Induced potential test.
L. Excitation current.
M. IR, IX and IZ percentages.
N. Reference and ambient temperature.

• Warranty- Transformers should be warranted against defects in materials, workmanship and performance for 10 years from date of manufacture.

It has been impossible to give all the points and suggestions that might assist you in choosing the manufacturer. The purpose of this article is to make you aware of the important points. Fine a manufacturer that shows you superior customer service, quality product, on-time delivery and expert technical assistance.

Great Power Transformer Articles

1. Top 20 Things to Know before Selecting a Power Transformer  - This is a great article to help educate and inform you on how to select the right transformer before you buy. It will help you make an informed decision and covers questions including, what voltage power output do you need?, will it be single phase or three phase?, etc. We answer the 20 most asked questions so you can be well informed and choose the right transformer for the job. Choosing the right transformer can be a daunting task for the inexperienced. This section takes the first step toward becoming a confident, knowledgeable consumer. This article addresses the process of choosing these transformers at its most fundamental level.

2. How Does Transformer Manufacturer Company Brand Affect Power Transformer Quality? - For manufacturers of large power transformers, product design and features seem fairly standard. But different manufacturers offer unique features. there are several standards such as ASTM D 3487 and IEEE Standard C57.12.90. Quality transformers can have a significant impact on cost. Did you know that some transformers brands improved materials, design and quality can save you 30%, or more, in energy cost? Understanding the differences can play a key role in making an informed selection.

3. How Does Winding Metal Type Change a Transformers Properties? - gain knowledge on how the winding and types of metal used can change transformer properties. The conducting material used for the winding depends upon the application. Small power and signal transformers are often wound with solid copper wire. Larger power transformers may be wound with copper wire, or aluminum and may include rectangular conducts. When copper wiring is used it will increase the efficiency of the transformer and will generally generate a lot less heat. Read more to learn about the many other efficiencies gained by choosing a transformer with a metal composition that is fit for your needs

4. Understanding Power Transformer "K-Factor Rating" - A great information article on what "K-Factor Rating" is and the effects they have on transformer choice. The K-Factor rating assigned to a transformer and marked on the transformer case in accordance with the listing of Underwriter Laboratories. It is an index of the transformer's ability to supply harmonic content in its load current while remaining within its operating temperature limits.

Read Addition Power Transformer Articles - Additional informal helpful articles about power transformers.

 Power Transformer Information:

Power Transformer Manufacturer

• ACME Transformers - 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 transformer market.
• 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 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 makes.
• 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.
• More power transformer brands - Check out more companies by clinking this link.

 Power Transformer Types

• 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 per second.
• 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.

  Power Transformer Types

• 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. -
• Step-Down Transformers - A Step-Down Transformer is  designed to reduce voltage from primary to secondary.  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 electric motors.
• 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.
• More power transformer types - Read further about additional transformer types and their uses.

Power Transformer Term Definitions

• Electrical Transformers - 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.
• Isolating Transformers - 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. 
• Transmission 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 electromagnetic or acoustic waves as well as electric power transmission. Components of transmission lines include wires, coaxial cables,  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 Phase - Most transformer are either single phase or three phase.
• 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 electrical equipment.
• Primary Voltage - The coil winding that is directly connected to the input power.
• Secondary Voltage - The coil winding  supplying the output voltage.
• 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.
• Weatherproof - Enclosed transformers come with a weatherproof standard set by NEMA.
• 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 conditions.
• More power transformer terms - Such as inductor, ground fault, core saturation, current transformer, faraday shield, etc.

Related Transformer Products

• 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 power supply.
• 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.

For an additional resource the Best of Industry Web Directory : Electrical Power Transformer Directory section is quite useful.