The losses during transformer operation include two parts:
(1) It is caused by the iron core. When the coil is energized, the magnetic lines of force are alternating, causing eddy current and hysteresis losses in the iron core. This loss is collectively called iron loss.
(2) It is caused by the resistance of the coil itself. When current passes through the primary coil and secondary coil of the transformer, there will be a loss of electrical energy. This loss is called copper loss.
The sum of iron loss and copper loss is the transformer loss. These losses are related to the transformer capacity, voltage and equipment utilization. Therefore, when selecting a transformer, you should try to make the equipment capacity consistent with the actual usage to improve equipment utilization, and be careful not to operate the transformer at light load.
What is a transformer nameplate? What are the main technical data on the nameplate?
The nameplate of the transformer indicates the performance, technical specifications and usage occasions of the transformer to satisfy the user's selection. The main technical data that should be paid attention to during selection are usually:
(1) Kilovolt-ampere of rated capacity. That is, the output capacity of the transformer under rated conditions. For example, the rated capacity of a single-phase transformer = U line × I line; the capacity of a three-phase transformer = U line × I line.
(2) Rated voltage volts. Mark the terminal voltage of the primary coil and the terminal voltage of the secondary coil (when no load is connected) respectively. Note that the terminal voltage of the three-phase transformer refers to the line voltage U line value.
(3) Rated current amperes. It refers to the line current I line value that the primary coil and secondary coil are allowed to pass through for a long time under the conditions of rated capacity and allowable temperature rise.
(4), voltage ratio. Refers to the ratio of the rated voltage of the primary coil to the rated voltage of the secondary coil.
(5), wiring method. Single-phase transformers only have one set of coils for high and low voltage, and are only for single-phase use. Three-phase transformers have Y/Δ type. In addition to the above technical data, there are also the rated frequency, number of phases, temperature rise of the transformer, impedance percentage of the transformer, etc.
