A step-down transformer reduces the voltage from a higher level to a lower level, while a step-up transformer increases the voltage from a lower level to a higher level.
Yes. The Va numbers indicate the rating of the transformer (12VA indicates that you can draw upto 12/24 = 1/2 Amps at 24 volts and 20VA indicates that you can draw about 20/24 = 0.83 Amps). Usually 20va transformer will cost more than the 12va transformer. So, unless a higher power output is required, it is adequate to use the lower rating transformer. However, you cannot go the other way - if you use a 12va transformer in-lieu of the 20va one, if the application needs more power, then you have a reliability problem. The transformer will have more loss, heat-up and then eventually burn out.
A transformer works with alternating current (AC). The primary coil of the transformer is connected to an AC power source, which creates a changing magnetic field that induces a voltage in the secondary coil.
A Tesla coil is a device that uses resonance to boost an electrical signal to many times its original amplitude. The primary and secondary coils function as a step-up transformer which converts relatively low current at high frequencies.
Close approximation of the primary and secondary coils makes for an efficient transformer. It is the rise and fall of the magnetic field that surrounds the wire in the primary that induces a current to flow in the secondary. The closer the wire producing the magnetic field is to the conductor being cut by the magnetic field (induction) the better the secondary output.
transformer is not rotating bcoz for rotating rotating magnetic field is required which is produced only when the current is passed through the windings which are displaced physically by 120degrees and phase difference of 120 degrees where as in transformer there is no phsical displacement of 120degrees hence transformer cannot rotate.
No
The transformer will act as a step down transformer in the ratio of 240 to 208. This will reduce the 208 input to 180.
To limit the current flowing through the primary circuit.
When the secondary of a transformer is opened, there is no longer any load on the transformer. There will be some current flowing in the primary winding, which is needed to induce the voltage in the secondary. This primary current is referred to as the "no load" current, and is indicative of the core losses in the transformer.
The function of an isolation transformer is to electrically-isolate the secondary circuit from the primary circuit, without changing the voltage levels. So, its secondary voltage will be the same as the primary voltage.
A step-down transformer accepts a given voltage on the primary winding (coil), and outputs a lower voltage on its secondary winding. A good example is a doorbell transformer you might buy for your home. It uses 120 volts from the house electrical system and steps it down to a safer 18 volts used to ring the doorbell. The voltage produced is a function of the 'turns-ratio' of the transformer. For example, if the transformer has 500 turns of wire in the primary, and 125 turns of wire in the secondary, we would say it has a turns ratio of 4:1 (pronounced "four-to-one"). If we feed 120 volts into the primary, the secondary would produce 30 volts. 120:30 = 4:1
No, the primary winding VA does not necessarily equal the secondary winding VA when a transformer is loaded. The power output on the secondary side may differ from the power input on the primary side due to losses such as resistive and core losses in the transformer. The transformer's efficiency will determine how close the VA on the primary winding is to the VA on the secondary winding.
A transformer is the primary device which transforms voltage to a higher or lower voltage. In electronics, capacitors and resistors perform this function.
This isn't the case. You can have aluminium or copper on primary or secondary side of a transformer.
I am assuming the question is about the power / distribution transformer and not the current transformer. The primary current is a function of load connected on secondary. With the open secondary, there is no load, no current, it is open circuit. Hence no primary current. However there is always some small amount of no load current in the primary winding.
A '33-kV transformer' is a three-phase primary-distribution transformer, used in the UK's electricity system to step down the 33-kV primary-distribution voltage to the 11-kV secondary-distribution voltage -the lowest voltage used in the high-voltage distribution system. These transformers are categorised as 'power transformers', and are located in what are termed 'primary substations'.
The incoming voltage from the source to the transformer is called primary voltage.