CHAPTER THREE: TRANSFORMERS
what is The cooling class designation for a self-cooled transformer ?
OA
what is The cooling class designation for forced-air-cooled transformer ?
OA/FA
What are A forced-air-cooled dry type transformer ?
A forced-air-cooled dry type transformer is cooled by means of forced circulation of air through the encloser, Transformers of this type have air-blast equipment such as fans with louvered or screened openings, These transformers are rated at 133 percent of the rating of the self-cooled dry-type transformer.
What are self-cooled transformer of the dry type ?
A self-cooled transformer of the dry type is cooled by natural circulation of air through the transformer encloser.
what is cooling class designation for self-cooled transformer of the dry type ?
AA
Dry-type transformers can be obtained with both self-cooled and forced-air-cooled rating. The designation for such a transformer is____?
AA/FA
what is Askarel ?
Askarel is a nonbiodegradable fluid and highly toxic.
what is The cooling class designation for water-cooled transformer ?
F,O,W
what is The cooling class designation for forced-air-cooled dry type transformer ?
FA
who invented the transformer ?
In 1886 William Stanley invented the transformer.
what is forced-air-cooled transformer ?
In the forced-air-cooled transformer, air is forced over the cooling surface of the tank to supplement the self-cooled rating. the supplemental air is provided by fans mounted on the transformer tanks, which can be manually or automatically controlled.
how are transformers generally classified ?
Method of cooling, Insulation, Number of phases, Method of mounting, Purpose, Service.
what is The cooling class designation for forced-air-cooled and forced-oil-cooled transformer?
O,A,/,F,A,/,F,O,A,
What are Reactors ?
Reactors are inductance coils utilized in power systems to limit current during fault conditions.
What are The dry-type transformer ?
The dry-type transformer can either be self-cooled or forced-air-cooled.
what is forced-air-cooled and forced-oil-cooled ?
The forced-air-cooled and forced-oil-cooled transformer uses a pump to circulate oil through a heat exchanger to increase heat dissipation, which supplements the self-cooling and forced air cooling.
how is energy lost in transformers?
The heat energy is from the , I , 2, R, losses in the transformer wingdings and from the hysteresis and eddy current losses in the transformer core.
The transformers utilized at substations can be categorized as what ?
The transformers utilized at substations can be categorized as either power transformers, distribution transformers, instrument transformers, or, special purpose transformers.
What are water-cooled transformer ?
The water-cooled transformer uses water instead of air to provide the cooling. The cooling system consists of a heat exchange by means of water pumped through a pipe coil installed inside or outside the transformer tank.
what is Transformers ?
They are devices used in AC Power Systems to convert electrical power, at one voltage or current) into electrical power at some other voltage or current.
What are Transformers used for ?
Transformers change voltage and inversely change current. they also my serve for electrical isolation and to change impedance.
Name Two examples of special-purpose transformers .
Two examples of special-purpose transformers are the arc furnace transformer and, the rectifier transformer.
What happens when two coils of wires are inductively coupled ?
When two coils of wires are inductively coupled, the magnetic flux that passes through one coil passes through the other to the same degree. Thus, the magnetic circuit is common to both coils.
What are self-cooled transformer ?
a self-cooled transformer uses the natural circulation of the insulating liquid. Heat in the transformer tank is dissipated by convection currents set up in the liquid, which circulates through the tank and cooling fins.
Alternating current is also subject to power losses in transmission by what effect ?
current to the power of two, times , resistance.
The transformer cooling medium can be subdivided into two types, name them.
dry and liquid filled.
Insulation of transformer coils from each other and from the core is performed in two different ways, name them.
dry-type insulation and oil-filled insulation
what is liquid-filled transformer ?
in a liquid-filled transformer the wingdings and core are totally immersed. in liquid contained in the transformer tank. The tank is equipped with cooling fins for circulation of the transformer liquid.
Name Two liquids that have been used extensively in the past for transformers .
mineral oils and polychlorinated biphenyls (PCB), commonly known as Askarel.
What are power system capacitors used for ?
power system capacitors used to increase the power factor of an electrical system
what is furnace transformer ?
the arc furnace transformer is a low-voltage and high-amperage transformer and is specially braced to withstand mechanical stresses caused by fluctuating current requirements. Due to distorted waveform bee use of arcs it has extra insulation and impedance in its winding circuits.
What are The rectifier transformer used for ?
the rectifier transformer is used in the rectification of alternating current to direct-current applications in process industry.
what did scientist Michael Faraday discovered in 1831 ?
the scientist Michael Faraday discovered that when a mechanical motion was introduced to move a closed circuit conductor in a magnetic field, an electrical voltage was produced that caused a current to flow.
