Transformer is transformed AC voltage, current and impedance of the device, when there is communication through the primary coil current, the core (or core) will be generated in the exchange flux, so the secondary coil induces a voltage (or current). Transformer from the core (or core) and the coils, there are two or more coil windings, then the power which called the primary coil windings, and the rest is called the secondary coil windings.
First, the classification
By cooling Category: Dry (from cold) transformer oil (from cold) transformer, fluoride (evaporative cooling) transformer.
Moisture-proof manner by Category: Transformer company, encapsulated transformers, sealed transformers.
Core or coil structure by Category: core-type transformer (core inserts, C-type core, ferrite core), shell-type transformer (core inserts, C-type core, ferrite core), Toroidal transformer, metal foil transformers.
Classified by the number of power phases: single-phase transformers, three phase transformer, multi-phase transformer.
Classified according to purpose: power transformers, regulating transformers, audio transformers, IF transformers, high frequency transformers, pulse transformers.
Second, the characteristic parameters of power transformer
An operating frequency
Transformer core loss with frequency in it it should be based on frequency of use to design and use of this frequency is called frequency.
2 rated power
The required frequency and voltage, the transformer can be long-term work, not exceeding the prescribed temperature of the output power.
3 rated voltage
Means allowed by the coil of the transformer voltage applied, work shall not exceed the specified value.
4 voltage ratio
Refers to the transformer primary voltage and secondary voltage ratio, there is no-load voltage and load voltage ratio than the differences.
5 no-load current
Transformer secondary is open circuit, there is still some of the primary current, this part of the current known as the no-load current. Load current from the magnetizing current (generated flux) and iron loss current (caused by the core loss) component. For 50Hz power transformer, the load current is essentially equal to the magnetizing current.
6 No-load loss: refers to the transformer secondary is open circuit, measured in the primary power loss. The main loss is core loss, followed by no-load current in the primary coil to generate a loss of copper resistance (copper loss), this part of the loss is very small.
7 Efficiency
Refers to the secondary power ratio P2 and P1 the percentage of primary power. Transformer rated power is usually greater, the higher the efficiency.
8 Insulation resistance
Said transformer between the coils, each coil and core insulation between. The level of insulation resistance and insulation materials used in the performance, the degree of temperature and moisture level.
Third, the audio transformers and Power line Conditioner parameters
A frequency response
Refers to the transformer secondary output voltage changes with the frequency characteristics.
2 passband
If the transformer in the middle frequency of the output voltage of U0, when the output voltage (input voltage) when the frequency drops to 0.707U0 range, known as the transformer's pass band B.
3 primary and secondary impedance ratio
Transformer primary and secondary access to the appropriate impedance Ro and Ri, the transformer primary and secondary impedance matching, the ratio of Ro and Ri is called the primary and secondary impedance ratio. In the case of impedance matching transformer work in the best condition, the maximum transmission efficiency.