Transformer Buying Guide
A transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil and the iron core (magnetic core). The main functions are: voltage transformation, impedance transformation, isolation, etc. According to different uses, transformers can be divided into several categories. Today we mainly introduce the applications and advantages of isolation transformers, toroidal Transformers, control transformers, and autotransformers, so that you can make better choices when purchasing.
Isolation transformer refers to a transformer with electrical isolation between the input winding and the output winding. The isolation transformer is used to avoid accidental contact with live objects at the same time. The isolation transformer is to isolate the respective currents of the primary and secondary windings. It is widely used in the control power supply of general circuits, safety lighting and indicator lights in the electronic industry or industrial and mining enterprises, machine tools and mechanical equipment.
We should pay attention to the following if we can to buy an isolation transformer:
Isolation transformers are safe power supplies, generally used for machine repair and maintenance, and play the role of protection, lightning protection, and filtering.
- The AC power supply voltage we usually use is connected to the ground with one wire, and there is a potential difference of 220V between the other wire and the ground. If human contact it, it can cause electric shock. The secondary winding of the isolation transformer is not connected to the ground, and there is no potential difference between any two lines of it and the ground. People will not get electric shock when they touch any line, so it is safer.
- The output end of the isolation transformer is completely "open circuit" isolated from the input end, which effectively plays a good filtering role on the input end of the transformer (power supply voltage supplied by the grid). Thus, a pure power supply voltage is provided to the electrical equipment.
Toroidal transformer is a large type of electronic transformer and has been widely used in home appliances and other electronic equipment with high technical requirements. Its main use is as a power transformer and an isolation transformer.
When we buy a toroidal transformer, we need to know that it can be used in the following fields:
- Audio equipment
Among the toroidal transformer products, there are many well-known products in audio equipment. Such as high-performance products that can be used as power transformers in high-power hi-fi amplifiers and power transformers for medium and small power audio equipment.
- Electrical control
It can be used in current and voltage transformers. New high-performance magnetic materials such as permalloy soft magnetic materials, amorphous materials or nanocrystalline alloys can be used as magnetic cores, with precise intelligent instruments and special testing methods. It can ensure accurate transformer parameters and completely consistent performance.
- Medical equipment
Toroidal transformers are specially designed and manufactured for medical equipment. In addition to high efficiency, high reliability and high safety requirements, it also specially strengthens the electrical strength and improves the anti-humid heat performance. A thermal fuse is also required to be added inside the transformer to ensure reliability.
The advantages of toroidal transformers are as follows:
- Small size and light weight
Toroidal transformers are half the weight of laminated transformers. As long as the cross-sectional area of the iron core is kept equal, the toroidal transformer can easily change the ratio of the length, width and height of the iron core, and the external dimensions that meet the requirements can be designed.
- The magnetic interference is small.
The toroidal transformer core has no air gap, and the windings are evenly wound on the toroidal core. This structure results in low magnetic flux leakage and low electromagnetic radiation, and can be used in high-sensitivity electronic equipment without additional shielding, such as low-level amplifiers and medical equipment.
- The noise is small
The vibration noise is small, and the iron core has no air gap, which can reduce the iron core.
The control transformer is mainly suitable for AC 50Hz (or 60Hz), voltage 1000V and below circuits, and it can work continuously for a long time under rated load. It is usually used in machine tools and mechanical equipment as the control lighting and indicator power supply of electrical appliances.
The control transformer is a small dry-type transformer. It is often used as local lighting power supply, signal lamp or indicator light power supply, and as control circuit power supply in electrical equipment.
When we purchase control transformers, we should pay attention to these safety requirements:
- Insulation resistance
The insulation resistance of the control transformer in the cold state shall not be lower than 10 MΩ; the insulation resistance of the control transformer in the hot and wet state shall not be lower than 2 MΩ.
- Dielectric strength
The electrical insulation strength of the control transformer should be able to withstand the withstand voltage test of AC 50 Hz, 2 000 V sinusoidal AC voltage, and no breakdown or flashover occurs for 1 minute.
- Leakage current
The leakage current of the control transformer shall not exceed 3mA.
An autotransformer refers to a transformer whose windings are on the same winding as the primary and secondary windings, and the primary and secondary windings are directly connected in series and self-coupling. According to the structure, it can also be subdivided into adjustable pressure type and fixed type. Common AC (manual rotation) voltage regulators, transformers in small household AC voltage regulators, transformers in three-phase motor auto-decompression starter boxes, etc., are all application examples of autotransformers.
With the rapid development of power systems in the direction of large capacity and high voltage, autotransformers are widely used in high-voltage power networks due to their low cost and high efficiency, becoming a voltage conversion device for transmitting important electrical energy. As one of the most important equipment in the high-voltage power grid, the autotransformer is of great significance to ensure the safe and reliable operation of the power grid and to distribute the power flexibly.
We need to know these advantages when buying an autotransformer:
- Less consumption of materials and low cost.
As the amount of silicon steel sheet and copper wire used in the transformer is related to the rated induced potential and rated current of the winding, the material consumption is also reduced, and the cost is also low.
- Less loss and high benefit.
Due to the reduction in the amount of copper wire and silicon steel sheet, at the same current density and magnetic flux density, the copper loss and iron loss of the autotransformer are lower than those of the double-winding transformer, so the benefit is higher.
- Easy to transport and install.
It is lighter in weight, smaller in size and smaller in footprint than a dual-winding transformer of the same capacity.
These transformers are sold on ATO website. If you want to know more information or buy our products, please click the link for details