Electric Transformers
Electric transformers are static electrical machines that transform electric power from one circuit to the other without changing the frequency. An electrical transformer can increase or decrease the voltage with...
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This Article takes an In-depth look at Electric Transformers
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Electronically operated equipment depends on power transformers to convert electrical currents into voltage. Current transformers store and transport energy through power lines and grids. Electric transformers inductively couple electro-magnetic devices to transfer electrical energy from one circuit to another. The main purpose of a transformer is to step up or step down voltage levels to meet a device‘s requirements.
Electric transformer manufacturers configure transformers to meet all types of electric applications in a variety of sizes, from thumb-sized for electric lamps or microphones to huge stationary transformers in power facilities.
Low voltage transformers convert electrical currents to fit appliances such as dimmer lights and small electronic devices, while high voltage ones are used in the transmission of electricity between power generation facilities and points of consumption.
Most transformers are isolation types to transmit electricity through induction using a single phase. Three phase versions are capable of transforming electricity in three phases with each phase having the same amount of voltage described in degrees.
A major benefit of electric transformers is their use as a safety device to protect users and equipment. Safety is a great major concern when dealing with electricity since using voltage that is too high or low can cause adverse problems. Excessive voltage causes a device to fail or be destroyed. In severe cases, high voltage can lead to fires and electric shock, while low voltage can cause a device to underperform. Electric transformers configure the dispensing of voltage so that it is appropriate for the receiving device.
Electric transformers have two sets of coils, or windings, linked by a magnetic core of iron, a ferrite compound, or a laminated one wound with copper or enamel coils. In an electrical motor, AC voltage is received by a primary coil that produces a magnetic field of voltage that surrounds the conductor. The magnetic field activates a secondary conductor coil. The transformer changes the voltage of the magnetic field and transfers electrical energy.
An important factor in producing electricity is the number of windings on a coil, which determines the voltage sent from the primary to the secondary conductor. The ratio of turns (windings) in the primary coil to the number of turns in the secondary coil decides the magnitude of the voltage. Step-down transformers have fewer turns in the secondary coil than in the primary, while step-up transformers have more secondary coil windings than the primary.
When voltage conversion is completed, energy is transferred to the load center, and the electrical process continues. The size and expense of electric transformers is determined by the number of primary windings.
The concept of the transformer owes its existence to the work of Michael Faraday who hypothesized that if magnetism is produced by electricity then electricity can be produced by magnetism. It is that conceptualization that stands at the center of how a transformer works.
Transformers use the properties of electricity to change the voltage of electricity. Electric circuits have magnetism. Whenever the magnetism changes, by moving or alteration of its strength, voltage, the measure of electric force or power, is produced. If an electric wire is close, when the change occurs, electricity will flow into the wire.
A transformer takes in electricity at high voltage and runs it through coils that are wound around a core. The current is alternating making the magnetism alternate. The core has an output wire wrapped around it with fewer coils. The fluctuating magnetism produces current in the wire.
For electricity to travel from a power plant, it has to be sent at very high voltage to be able to cover the distance, which can be 155,000 to 770,000 volts. The receiving location has to lower the voltage, or step it down, to be used. Power distribution systems have substations that break down the high voltage into smaller increments and step it down.
Locally, another transformer changes the voltage from the substation from 7200 volts to the normal 220 or 240 to be used for air conditioners, heaters, and appliances. For other items such as toys, computers, and televisions, the voltage is stepped down further to 110 or 120.
To step voltage down, there have to be more wires on the primary winding than on the secondary one. To step voltage up, there have to be more windings on the secondary winding than on the primary. It is very uncommon for the primary and secondary windings to be the same. If they do, the voltage would remain the same.
Regardless of the design of a transformer, there is always lost energy that dissipates in the form of heat. If the heat is uncontrolled, it will deteriorate the insulation on the wiring. Since a transformer is static, they are very difficult to cool.
Cooling of a transformer comes in two forms – air and oil. The dry or air form of cooling uses circulating ambient air to carry away the heat or, when circulating air is not enough, air blasts are used to force air on the coils and keep the temperature down. An oil cooling system immerses the transformer in circulating water or oil.
As has been shown, the purpose of a transformer is to step voltage down or up to meet the needs of an application. Its development has given us the ability to share electricity over long distances and keep electrical use safe.
One of the problems that can decrease the efficiency of an electric transformer is eddy currents, or Foucault’s currents, which are loops of electrical current induced in a conductor by changes in the magnetic field in a conductor. Eddy currents flow in closed loops perpendicular to the plane of the magnetic field and produce heat.
In the production of electric transformers, manufacturers use core materials and processes to eliminate or lessen the effects of eddy currents. When eddy currents are present in an electric transformer, they create heat which leads to energy loss and decreased efficiency of a transformer. To prevent eddy currents, manufacturers use materials for the cores of transformers that have low electrical conductivity and high resistivity or resistance to electrical current.
All transformers work off of the Faraday law with specialized types designed for various applications. As new innovations and products are introduced, there are transformers developed to monitor and control the current and voltage the new devices require.
The core of an iron core transformer is a set of multiple iron plates, which have excellent magnetic properties making iron core transformers very efficient. The sheets of the plates are made of silicon steel with insulation painted on their surface. Magnetizing and demagnetizing happens very quickly with iron core transformers making them the perfect choice.
Magnetizing and demagnetizing happens very quickly making iron core transformers a perfect choice. The magnetic properties of iron core transformers gives them a very high linkage flux, which is one of the reasons for their exceptional efficiency.
The configurations of iron cores are the types E, I, L, and U with the majority of iron cores using a combination of the types. Sheets of metal are used for iron cores due to the fact that solid iron cores have wasteful eddy currents. Iron core transformers are used with computers, televisions, radios, and amplifiers.
The wide use of iron core transformers is due to their highly inductive electromagnetic flux and their ability to transfer flux fifteen hundred times faster than air core transformers. The benefits of iron core transformers are their power transfer abilities, low magnetic flux loss, and their ability to handle large loads at low frequencies and high voltages.
The role of isolation transformers is to transmit electrical power to a device from a power source. Technically, all transformers can be defined as an isolation transformer, due to the fact that all transformers use the process of induction to convert electricity, as opposed to the use of a conductor. The main characteristic that sets isolation transformers apart from other categories of transformers is their ability to isolate electricity or isolate a transformer from a power source. Numerous applications use isolation transformers. These applications include uninterrupted power supplies (UPS), test and measurement systems, robotics, motor controls, light fixtures, medical electronics, industrial control panels, data communications, avionics, and audio systems.
An isolation transformer isolates primary and secondary windings and keeps the circuits separated. Electrical energy is transmitted between circuits by magnetic induction that uses a magnet to generate an electromagnetic field (EMF) in a circuit without affecting the frequency. Isolation transformers separate power line ground connections to eliminate ground loops and suppress high frequency noise.
Isolation transformers provide isolation between AC main power lines and powered equipment and eliminate a DC path between windings. They isolate the secondary from the ground, provide step up or step down of main line voltages, and reduce line noise.
The permeable magnetic qualities of ferrite core transformers control the loss of energy in high frequency applications. They can be shaped and fitted to any function and have an E type core configuration. The windings for ferrite cores are made of non-conductive, ceramic, ferromagnetic compounds that contain iron oxides combined with nickel, zinc, and manganese, which have low coercivity and are soft ferrites.
The ceramic material in ferrite cores serves as an insulator. Ferrite cores are resistant to high currents and provide low eddy current loss over many frequencies. The high magnetic permeability of ferrite cores and their low electrical conductivity is how they prevent eddy currents.
There are four different types of ferrite cores, which are manganese zinc (MnZn), nickel zinc (NiZn), sand dust, and lamination. Manganese zinc ferrite core transformers have high saturation levels and permeability. They are used with applications that have operating frequencies that are less than 5MHz and are ideal for inductors above 70 Mhz.
Nickel zinc ferrite core transformers have high resistivity and are used in applications with frequency ranges of 2 MHz to several hundred MHz. They are suitable for inductors over 70 Mhz. Sand dust are high frequency choke coils that are used exclusively with ferrite cores while lamination transformers are manufactured for use with inverters, welding sets, and uninterruptible power supplies (UPS).
Audio output transformers modify input electromagnetic signals into output signals using inductive coupling. In the process, an input circuit is isolated from an output circuit and filter signals. They have applications in the input stage, microphones, and output stage, loudspeakers as well as coupling and impedance of amplifiers. Audio output transformers have the same primary and secondary windings as other forms of transformers with copper wire windings wound around steel or nickel iron alloy cores.
The cores of audio output transformers transmit electromagnetic signals differently. Steel cores have a higher degree of hysteresis, which makes them better for lower frequencies. The permeability of nickel makes nickel iron alloy cores the best choice for transmitting high frequencies. The windings around the core determine the level of impedance that increases, decreases, or maintains the signal.
Audio output transformers use their isolation property to create isolation between the output or audio circuitry and the input amplifier side of the transformer. The ratio between the primary and secondary windings can be 1:1 since the transformer may not alter the voltage or current level. In the case of loudspeakers that require a huge load, an audio output transformer will step up the load to produce the proper speaker vibrations.
The use of audio transformers is important for matching the impedance of one circuit or device that is connected to the input of another device. This is especially important in relation to speakers and microphones such that the impedance matching converts impedance to a level that is appropriate for a speaker or another device.
Step up transformers are commonly used in applications such as power transforming and modification, due to their ability to convert lower voltages to higher voltages while reducing amperage and the effects of resistance in the process. The voltage conversion entails electrical energy traveling through two phases of coils, with the second coil phase having a greater amount of winding, defined as a complete coil assembly. Some applications require only a single coil winding, and others even require a tertiary set of windings. However, electric transformers require two to complete the conversion process. These two sets of coil windings feature a core being made from either a ferrite compound or a laminated core wound with enameled coils or uncovered copper. The coil windings of step up transformers are typically constructed from aluminum, nickel, chromium, steel alloys, and copper, the latter of which is the most expensive yet is the most energy efficient.
High voltage transformers are tools used to change the voltage of power lines in high voltage contexts. A volt is the unit of measurement for electromotive force, and the voltage of a power transmission line is the measurement of power transmission capacity in a transmission line.High voltage transformers are built to handle elevated amounts of electrical energy in the range of 600 to 5,000 volts, although custom voltage transformers are available as well. A type of instrument transformer, high voltage transformers are often used for metering and protection in high-voltage circuits and in electrostatic industrial and scientific applications.
The configuration of high voltage transformers includes single phase primary and three phase. The types of single phase primary transformer configurations include single, dual, quad, five lead, and ladder. Five lead primaries require more copper in their construction while ladder types are the most expensive and costly.
Three phase high voltage transformers are connected in delta and wye configurations. Wye delta high voltage transformers have the primary winding in the shape of the letter “Y” while the secondary winding is in the shape of a triangle. With the delta wye configuration, the primary is in the shape of a triangle while the secondary is in the shape of the letter “Y”.
The donut shape of the toroidal core transformer prevents induction leakage creating high inductance. Windings are short, and the transformer weighs less than others with the same rating. They are expensive because of the slow winding process.
Toroidal cores are ideal for sensitive and critical electronic circuits due to their high efficiency, quiet operation, low heat generation, and compact design. They are widely used with audio systems, control equipment, and power converters.
The efficiency of a transformer is the ratio of the output power of the secondary winding to the supply of power to the primary winding. A typical toroidal core transformer has an efficiency rating of 95% to 99%, which is due to the perfect design of toroidal core. Since the magnetic flux of a toroidal transformer is concentrated in the coil windings and evenly distributed, it effectively couples the primary and secondary windings. An additional benefit of toroidal cores is their ability to shield adjacent components from EMI interference and is the reason they are used with sensitive electronic equipment.
A major benefit of toroidal transformers is the protection from electromagnetic interference (EMI) they provide for adjacent electronic components due to their donut shape design. Magnetic flux is contained within the transformer and is prevented from interfering with the performance of sensitive components. This is unlike solenoid cores that leak magnetic flux and require special shielding.
Air or antenna coil transformers do not have a magnetic coil as a core and are wound around plastic tubing or cardboard. They generate flux using coil windings that have air passing through the windings. The flux linkage is between two magnetically linked coils or windings, which are the primary and secondary windings.
The advantages of air core transformers include noise free operation, no loss of hysteresis or eddy currents, and lightweight. The two forms of air core transformers are cylindrical and toroidal. With cylindrical air core transformers, copper wire is wound in a cylindrical form. Tape is used for winding the primary coil while taps are placed in the windings of the secondary coil. The taps allow flux to flow through the hollow cylinder and encapsulate the winding. With toroidal air coils, copper wire is wound around a cardboard or plastic donut shape. The coil windings are used separately to minimize stray couplings. The ratio of primary to secondary windings is dependent on the type of operation and changes in frequency.
In high frequency applications, it is essential to avoid EMF distortions that significantly affect the output signal. Since ferromagnetic material produces noise and distortions, air core transformers are used where flux is linked with the windings using air. The efficient design of an air core transformer makes it noise free and lightweight for use in small handheld electronic devices.
The core of laminated transformers are made of punched sheets of iron and nickel that are laminated. The nickel reduces energy loss when the winding is energized. A main feature of a laminated core transformer is the reduction of eddy currents increasing the efficient transfer of energy from the primary coil to the secondary coil.
E-I laminated cores are used in isolation transformers as step-up and step-down transformers. Laminated cores have a cylindrical, rectangular, or oval shape with the stamped strips of metal taking configurations of E, L, U, or I’s. As with iron cores, laminated cores combine the configurations to form the shape of the core such as E configurations being combined with I configurations to form an E I core.
As current flows through the windings of a transformer, small currents may be induced into the core, which are called eddy currents. The reduction of eddy currents enhances the performance of a core. The lamination on laminated cores interferes with the induction of eddy currents increasing the efficiency of the transformer.
The laminating of the core of a transformer significantly reduces eddy current flow, which reduces heat loss. Circulating currents in iron cores cause heat build up and the loss of electrical efficiency. In extreme cases, the core’s temperature can increase to the point that it cracks and breaks. Laminated transformer cores reduce the production of heat to improve core performance.
Pulse transformers operate in a direct current (DC) mode, meaning that the flux density may meet but does not cross zero. A common application for pulse transformers is the coupling of a load resistance to a source of pulsed power. An example of this application would be radar transmitters, which typically employ an output power tube like a magnetron that requires high voltages and high impedance, or electric resistance, levels. Small versions of pulse transformers create the electrical surges that are often used in telecommunication and detail logic applications such as camera flashes, radar equipment and particle acceleration. Medium-sized versions of pulse transformers are used in electronic circuit applications.
Current transformers (CTs) are tools that are used to measure the current, or flow of electricity, in electrical transmission lines. Understanding a current transformer requires an understanding of electrical current, which is measured in amperes with one ampere being equal to the movement of 6.241 × 1018 electrons passed a given point per second. While power transformers control voltage, current transformers measure and control movement for measuring purposes and to help control the flow of electricity to electronic devices.
The primary winding of a current transformer has very few windings, which can be a single flat turn of heavy duty wire wrapped around a core or a bus bar placed through the central hole. Current transformers reduce high voltage current to a lower value and provide a way to monitor current flowing in an AC line using a standard ammeter. They are known as series transformers due to the fact that the primary windings are in a series with a current carrying conductor supplying the load.
Unlike the primary winding of a current transformer, secondary windings can have several windings wound around a laminated core of low loss magnetic material. The cross sectional area of the core is such that the magnetic flux density is low. The secondary winding supplies current to a short circuit in the form of an ammeter or into a resistive load.
Low voltage transformers are power transformers that are used to change the voltage capacity of a low-voltage electrical transmission line. Typically, electronic low voltage transformers convert 120 volts into 12 volts or 24 volts. Unlike high voltage transformers, which in the most extreme cases can weigh several hundred pounds, low voltage transformers can be small enough to hold between two fingers.
The main supply voltage for users is 120 volts in the United States, which can be dangerous. The purpose of a low voltage transformer is to step down the input voltage to a significantly lower value. The lower voltage makes it possible to operate equipment, install light bulbs, and complete other tasks with the electricity on.
The number of windings in the secondary winding of a low voltage transformer is much less compared to the primary winding. The primary and secondary windings are wound on a magnetic iron core but are not in contact with one another. The core is made of soft magnetic material consisting of laminations that are linked together to reduce loss, which is energy loss in the core caused by alternating magnetic flux.
Current flows through the primary winding when it is connected to the power supply. As current flows through the coil, a magnetic field is induced. Part of the magnetic field links to the secondary winding to produce current flow and voltage at the secondary load side, which is proportional to the number of turns in the secondary winding relative to the primary side.
Automatic or autotransformers have one winding that acts as the primary and secondary that are magnetically and electrically connected with three taps for electrical connections. They are smaller, lighter, and less expensive and are used where electrical systems have different voltages. Auto transformers consist of a single winding and an input and output circuit. The voltage source and the load are connected to two of the taps. One tap at the end of the winding serves as a common connection to the source and the load circuits.
A unique feature of automatic transformers is the electrical conductive link between the primary and secondary windings, which is unlike other transformers. The winding before the load is the primary winding while the winding that is in parallel to the load is referred to as the secondary or common winding. As a step up or step down transformer, an autotransformer applies the same rules with the only difference being the voltage across the load being larger than the source voltage.
Autotransformers operate like any other form of transformer where the primary current induces a varying current in the secondary winding according to the ratio of the turns in the windings. The secondary winding is tapped along its winding to allow output to be varied in different steps and percentages.
When there is a need for three phase power supplies, it is possible to have three individual single phase transformers to fill the need. A more efficient method is to have all three phases in a single transformer where the magnetic circuits are connected and the core has a three or multiple phase flow of flux. This type of transformer is referred to as a polyphase transformer, which has multiple sets of primary and secondary windings on a single core. The multiple windings make it possible for a polyphase transformer to have three or more conductors with as many as 15 phases.
The separation of phases in a polyphase transformer is by a phase break, or short circuit, that allows for more efficient power distribution and makes it possible for each phase to run at a different speed. Additionally, the amount of heat transfer from the on-off phase to the high voltage phase is significantly lowered by separating the phases. In the on-off phase, a polyphase transformer is hotter than its high voltage phase, which makes it easier for heat to flow to the rest of the system due to the smaller size of the on-off phase.
The primary and secondary in a polyphase transformer can be connected using wye and delta connections, which can be wye and delta or delta and wye. As long as there are no neutral wires, either form of connection works.
A zig zag transformers has six coils on three cores with the first coil of each core connected in the opposite way to the second coil on the next core. The second coils are tied together to form the neutral with the phases connected to the primary coil. In the process, each phase couples with the other phase and voltage is canceled.
Interconnected star or zig zag transformers are grounding transformers that do not have secondary windings but have winding connections that allow the flow of current in phase through the neutral. The zig zag formation is low cost with an iron core design that limits the flow of harmonic flux.
The windings for each phase of a zig zag transformer come in two halves. Thus, the difference in winding patterns results from the way in which the two halves of the windings interconnect while connecting the coils and the core. Zig zag connections have a high magnetizing resistance to the flow of positive and negative sequence currents with lower leakage resistance to triple harmonics and zero sequence current.
Zig zag transformers are used to define a reference point for ungrounded systems. Due to their ability to provide a neutral point for grounding purposes, numerous industries utilize zig zag transformers, including industrial, electronics, petrochemical, power distribution, automotive and hardware.
A three phase transformer falls into the realm of the polyphase variety. Though it is possible to connect three single phase transformers to make a three phase one, it is more economical and efficient to have all three phases compacted into one. They have three sets of primary and secondary windings, which can be star or delta configurations. Configurations can be delta-delta, star-star, or other combinations.
In order to manage a 3 phase electricity transmission system, 3 phase transformers are necessary to transform and direct electrical current away from power lines and into homes and places of business. A current transformer adjusts the current that flows from an electrical utility line into the systems that will make use of it. Power transformers are essential to the safe and effective operation of electrical systems as well as individual appliances.
Power transformers transmit electrical power from one circuit to another without changing the frequency. They use electromagnetic induction to transmit electrical power from generators and distribution primary circuits. Power transformers step up or step down voltage in distribution networks without the use of moving parts, a factor that gives them a static device status.
A Power transformer is large, sends energy to substations, and acts as a connection between generators and the grid. The three classes of power transformers are small, medium, and large with ratings from 30KVA to 700KVA. Due to their size, power transformers require a cooling agent and are normally submersed in oil. They use a three phase system, which is costly but more efficient than single phased systems with smaller versions of power transformers being single phased.
The windings for power transformers are made of copper or aluminum coil with copper being preferred due to its high conductivity and ductility. Laminated cores are used to reduce eddy current losses and hysteresis losses and are made of sheets of iron or steel. Tapper changers are connected to the high voltage winding to make fine voltage regulations and minimize core losses. To reduce the risk of sparking that would ignite the cooling oil of the transformer current is lower in the HV winding.
Current transformers (CT) and voltage transformers (VT) are measurement transformers. CT transformers lower the current signals for measurement while VT transformers lower voltage values to lower ones. Both types are designed to determine if power systems are accurate and safe and lower voltage values from high to low. They have magnetic circuits in their primary and secondary windings. CT transformers step down current such that the current can be easily measured using an ammeter. A VT transformer measures voltage and lowers voltage to 100 V or lower to levels acceptable for measuring instruments.
CT transformers sense current in single or three phase mains circuits and have a 1A or 5A AC secondary winding connected to a current, power, or energy meter, which allows the meter to be located away from the main wiring. They are available in a wide range of sizes with 50:5 to 4000:5 being the standard ratios. Split core models easily fit around existing wiring while solid core models are less expensive.
VT transformers step down the voltage to a lower voltage that can be measured. They have a high number of primary turns with a low number of secondary turns and are described in primary to secondary ratios and have extremely accurate turns ratio.
Distribution or Step down transformers convert higher voltages to lower voltages by transferring electrical energy through two coil stages with the second coil stage having fewer coil windings to lower the voltage level. Power outlet voltages vary geographically with the two most common outlet voltages being 220 volts and 110 volts, which are the voltage differences between countries with different outlet voltage standards.
With a distribution transformer, when AC voltage is applied to the primary winding, a fluctuating magnetic field is created in the transformer's core. The magnetic field induces voltage in the secondary winding at a lower voltage, which is due to a higher number of turns in the primary winding than in the secondary winding. The lower number of windings generates an EMF that is lower than that of the primary.
Step down transformers are highly efficient at up to 99% and provide output voltage without loss of power. They are less expensive, more reliable, and provide high current and low voltages. The types of distribution transformers include single phase, three phase, multi-tapped, pad mounted, and pole mounted.
A distribution transformer is the final step in the transformation of voltage in an electric power distribution system. They lower or raise voltage to a level that can be used by homes, businesses, and commercial buildings.
Auto transformers are single winding transformers that are similar to two winding transformers with the primary and secondary windings interrelated. One part of the winding is common to both sides of the transformer. In load condition, part of the load current comes directly from the supply while the remaining part comes from the action of the transformer. Auto transformers work as voltage regulators.
With an auto transformer, the primary and secondary windings are connected magnetically and electrically. The types of auto transformers are distinguished by their construction with one type having taps while the other type has coils connected to form a continuous winding.
Auto transformers are a cost effective substitute for three phase distribution transformers that are used to adjust supply voltage to meet load requirements. They are perfect for adjustments to commercial and industrial equipment and are a low cost method for providing accurate voltage. Since they have one winding, they are smaller than traditional transformers, which makes installation easier.
With an auto transformer, voltage transformation happens at tappings at points along the winding. The changing of point connections changes the voltage ratios. The connection between the primary and secondary windings makes it possible for an auto transformer to better regulate voltage. The downside is that they have lower impedance than isolation transformers and may not provide protection against spikes or fluctuations.
Transformers have become an essential part of modern society since they play an important role in the generation and distribution of electricity. Their single basic function is to increase or decrease alternating current. There is an endless number of uses for electric transformers due to their ability to control voltage and current in a wide range of applications.
Battery charging includes the use of a transformer, bridge rectifier, and an ammeter. The transformer steps down voltage while the bridge rectifier converts the transformer’s AC current to DC current. Connecting a transformer directly to a battery is not possible since it operates using current that is unacceptable to a battery. The rectifying method is the most common since it simplifies the conversion process.
Portable battery chargers have transformers built into them. They are not normal laminated core transformers but are ferrite core transformers. The high operating frequencies of handheld devices requires the use of small transformers that are compact enough and light enough to fit in a handheld battery charger. The DC current that is supplied to cell phones, computers, and handheld electronics has to be carefully controlled and is the reason small transformers are included in their chargers.
Transformers ensure the safe charging of batteries and prevent damage to a battery through the conversion process. Unregulated voltage can result in electrical surges. The controlled voltage that enters a battery prevents damage to the components of a battery.
The range of transformers for small electrical devices has been rapidly growing as electronics keep getting smaller and lighter. The range of new compact transformers covers a wide range of designs, configurations, and sizes with each capable of high performance and efficiency.
The success of a steel operation depends on a reliable and dependable power supply. Steel processing involves the use of unique and application specific processes that require different forms of power conversion. Continuous voltage control is a necessity when a transformer is on load and a requirement for steel production.
Electric arc furnace (EAF) transformers are a special type of transformer design to meet the requirements of electric furnace steel production. EAF transformers have all the characteristics of normal transformers with an overload capacity and short circuit mechanical strength. They have an adjustment mode for on load voltage regulation and excitation voltage regulation.
DC electric arc furnace transformers are widely used for steel production due to their cost and ability to perform in all conditions. They are able to manage frequent overvoltages and over currents generated by short circuits in a furnace. They come as air cooled and water cooled designs with currents up to 200kA. The cooling process makes it possible to regulate the heating process during operation. Included in their operation are cyclic loading and rectifiers.
In steel production, high voltage is required for melting and welding, while lower currents are needed during cooling. This wide range of temperatures is monitored by transformers.
In chemical processing, electrolysis is powered by transformers. During the electroplating of metals, such as copper, zinc, or aluminum, transformers regulate the electrical current that powers the chemical reaction allowing the current in the reaction to be managed. The temperature in the process has to remain stable, have electrical insulation, and work productively in corrosive environments. Rectifiers control periodic unidirectional electrolysis pulses of a current greater than the charging source.
Steel manufacturing involves melting, welding, molding, and cooling materials. The processes of melting and welding require a great deal of current while cooling uses low current. High voltage transformers are used to regulate the fluctuations in current during the manufacturing process. Step-up and step-down transformers are used at different places in the circuit to achieve the required current.
Electrolysis is used to separate homogeneous and non-homogeneous elements by breaking down their ions into simple substances. The process involves passing electricity through a substance to cause a chemical reaction. The flow of current is regulated, has to be continuous, and is achieved with the use of an electrical transformer.
Audio transformers are used in microphones, loudspeakers, and amplifiers and are designed to operate with signals that fall within the audible range with frequencies between 20 Hz up to 20 KHz. A key feature of audio transformers is their filtration of unwanted sounds or noise signals such that the audio device produces clear and clean sounds. The use of audio transformers has greatly enhanced recordings, movies, and live performances.
Transformers used in an air dry form generate a cooling effect, which is used in refrigerators to keep food fresh. Aside from their cooling effect, electric transformers are used to regulate current flow to refrigerators to avoid surges and voltage imbalances, a feature that keeps refrigeration units safe.
As with coolants, transformers are used in air conditioning units to convert the magnitude of the voltage supplied by the circuit board to the desired value, which allows the air conditioner and the fan to operate at the same time. The major benefits of electric transformers with electrical appliances are to enhance their performance, increase efficiency, and minimize power consumption.
Another common use of electric transformers with appliances are stabilizer circuits that are attached to appliances that operate on high current or voltages. The stabilizer takes the input signal and puts out an output signal that matches the electrical requirements of the household system. This process reduces the potential of appliance failure or damage. The transformer steps up or steps down the voltage or current, which is constantly compared to the ideal current for the system.
An interesting function of an electric transformer is performing as a DC blocker. This is accomplished by the number of windings in the coils, the distance between them, and the insulating material. These factors are designed to accept a particular type of signal through the circuit by their configuration and the connection of the transformer to the circuit. When an electric transformer is configured in a certain way, they allow alternating current (AC) signals to pass through but prohibit the passage of DC current.
An electric motor is an extended version of a transformer since the principle of a motor is like that of a transformer. Unlike a transformer that changes the voltage or current of a power supply to a level that fits the needs of an application, an electric motor converts electrical energy to mechanical energy and rotary motion. Transformers and motors operate on the principle of Faraday’s law of electromagnetic induction.
A transformer receives AC current and changes it into DC current or level of current that can be used by a motor. It is a static piece of equipment that does not have an air gap, which is the gap between the core and rotor magnets of a motor. In motors, the air gap is an essential part of their operation that affects the strength of the magnetic circuit and motor efficiency.
A lighting transformer system steps voltage down from a power supply to make it suitable for lighting fixtures. They are used in low voltage lighting systems to reduce voltage from 120 volts, which is normal for residential power, to 12 V or 24 V. Lighting systems provide electrical isolation to regulate the output voltage such that it remains constant, regardless of the changes in the input voltage, which is essential since the majority of lighting fixtures necessitate a certain voltage to operate properly.
The various types of lighting system transformers come in a wide range of sizes depending on the number of fixtures and the power requirements. They are mounted inside or outside lighting fixtures and have different types of control systems. The importance of lighting system transformers is their ability to provide safe and reliable electrical power for residential and commercial lighting.
The main reason for medical equipment transformers is for patient safety and providing continuous and reliable electrical power. They are isolation transformers that specialize in protecting against electrical shock by isolating the primary and secondary winding circuits of the transformer. Prevention of passage between the input and output circuits adds an extra layer of protection against electrical hazards.
The use of medical equipment transformers is based on three premises, which are patient safety, noise reduction, and compliance with healthcare safety standards. Patients in healthcare facilities are especially vulnerable to electrical accidents and must be protected from potential harm. Noise generated by various monitoring equipment can interfere in the performance of highly sensitive medical equipment and disrupt internal communications. All medical facilities are subject to strict regulations that are set by the FDA and medical oversight organizations.
There are different types of heating and cooling system transformers, which include furnace, AC, and heat pump transformers. The most common types of heating and cooling transformers are step up and step down transformers with step up transformers changing the voltage from high voltage AC 110 volts to low voltage AC 240 volts while step down transformers change the voltage from 240 volts to 110 volts and are used for industrial buildings.
Furnace transformers convert high voltage input to lower voltage output and include timers, ignitions, circuits, and temperature controls to maintain a set voltage level. They send a signal to the system that is used to open and close a series of relays and contacts that control system functions. When a thermostat switch closes and allows power through, a coil energizes the relay and generates a magnetic field that closes the switch, and the blower comes on.
All heating, ventilation, and air conditioning (HVAC) systems have a number of relays, controllers, and switches that ensure the parts of the system work in the correct sequence. Since the controllers of a HVAC system are extremely sensitive, they require a transformer, in the control box or air handler, to step down the voltage and is connected to the thermostat.
The two types of audio transformers are step up and step down transformers and 1:1 transformers. Regardless of the type, audio transformers are designed to increase or decrease the impedance of a circuit, convert a circuit from unbalanced to balanced or balanced to unbalanced, block DC current to allow AC current to flow, and isolate audio equipment from each other. Microphones use step up transformers that step up the signal level and impedance before leaving the microphone.
Audio transformers that are 1:1 transformers have the same number of windings in the primary and secondary windings. Their impedance is the same, and the signal level does not change. Audio signals pass unmodified, but DC voltage and radio frequency interference (RFI) are blocked. They isolate equipment and remove humming problems. Audio transformers allow for multiple outputs from a single mic using multiple secondary windings and change balanced signals to unbalanced ones or vice versa.
Normal residential voltage is 240 V and is ideal for tools that are used around the house and for DIY projects. For heavy duty projects, 110 V tools are used and require a transformer to operate. On work sites, 110 V tools are used for the safety and their ability to prevent accidents such as cable cutting.
Power tools for work sites are plugged into transformers that are supplied with 240 V, which needs to be dropped to 110 V to avoid the use of circuit breakers. A power tool transformer has two 55 V lines in order to form the 110 V. If a wire is damaged or an accident happens, voltage is halved for user safety.
Uninterruptible power supplies are used to provide backup power to equipment during power outages and voltage fluctuations. UPS systems use transformers to isolate the output from the input using galvanic isolation between the input and output. Isolation protects sensitive equipment from voltage spikes, noise, and electrical disturbances.
With a low frequency UPS, power flows through the rectifier, inverter, and transformer to the output where the transformer steps up the AC voltage level, protects the UPS from load disruptions, and provides isolation. The use of a UPS is different from emergency power systems and generators since it immediately provides protection from interruptions in the input power supply by switching to batteries or supercapacitors.
In some cases, the run time of a UPS may be short but allows time to institute different methods to restore power. All UPSs have surge protectors to protect equipment from voltage spikes. The main reason for the use of UPSs is protection for computers, telecommunication system equipment, and sensitive data collection centers.
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