Introduction
A three-phase servo transformer is a device that allows for the conversion of AC power from one voltage level to another. It is used for the control of electrical motors, controlling AC voltage by the application of input signal. The signal is used to regulate the position of the rotor and the resulting output power from the servo transformer. This allows for more accurate and less-frequent power adjustments to meet the application’s changing needs.
The three-phase servo transformer utilizes a rotating core with three sets of coils. A signal is applied to one of the coils and the resulting current induces a magnetic field which interacts with the two other sets of coils. Depending on the signal, the rotor will rotate and the output voltage will change accordingly.
Types
There are two main types of three-phase servo transformers: the piece-by-piece series wound flux device and the single-piece toroidal parts-in-outer type. The piece-by-piece series wound flux device is used for continuous operation and has higher quality than the later type. The single-piece toroidal parts-in-outer type can be used for variable speed operations of low-torque motors.
Power Rating
The power rating of a servo transformer is determined by its maximum output current. Typically this rating will vary from 1-300 amps and is based on the type of application the unit is to be used for.
Speed
The speed of a three-phase servo transformer is the time it takes for the rotor to rotate through one full revolution. Speed is determined by the amount of torque required to move a certain weight. Typically the rotor speed is controlled by a feedback signal or an external voltage.
Input and Output Voltage
The input and output voltage of a three-phase servo transformer depend on the power rating and speed of the unit. The output voltage will usually be 1-2 times greater than the input voltage and is determined by the ratio of turns on the coils.
Output Waveform
The output waveform of a three-phase servo transformer is determined by the type of application the unit is used for. The common output waveforms are sine, sawtooth, and square. Depending on the application, the output waveform may be modified for better control and accuracy.
Size and Weight
The size and weight of a three-phase servo transformer depends on the power rating and the type of transformer used. The larger the power rating, the larger the transformer will be.
Efficiency
The efficiency of a three-phase servo transformer is determined by the power rating and the type of force used to move the rotor. The efficiency can be greatly improved by using an external or internal power source to reduce losses.
Cost
The cost of a three-phase servo transformer is determined by the size and power rating of the transformer and the type of material and components used. Generally, the larger and more powerful the transformer the more expensive it will be.
Conclusion
The three-phase servo transformer is an essential device in many modern electrical control applications. It provides a convenient and reliable way to control the output voltage of an electrical motor and allows for more accurate and efficient power adjustments. Different types, power ratings, speeds, and waveforms can be used to meet the changing needs of the application. The cost of the device will vary depending on the size and power rating of the transformer as well as on the type and quality of components used to manufacture it.
