Frequently Asked Questions

About Transformer

What is a transformer?

A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force (EMF) across any other coils wound around the same core. It is designed to change the voltage level of an alternating current (AC) power source to match the needs of a particular load. Transformers are commonly used in power distribution systems to step down the high-voltage transmission lines to a lower voltage for distribution to homes and businesses.

How does a power transformer work?

The transformer works on the principle of Faraday's law of electromagnetic induction and mutual induction. There are usually two coils primary coil and secondary coil on the transformer core. The core laminations are joined in the form of strips. The two coils have high mutual inductance. When an alternating current pass through the primary coil it creates a varying magnetic flux. As per Faraday's law of electromagnetic induction, this change in magnetic flux induces an EMF (electromotive force) in the secondary coil which is linked to the core having a primary coil. The transformer operates on the basis of electromagnetic induction, and it does not require any physical connection between the two coils. The magnetic field generated by the primary coil induces a current in the secondary coil, which is proportional to the number of turns in each coil and the magnetic field strength.

What are the differences between single phase and 3 phase isolation transformer?

Because of its simple structure and small size, the single-phase isolation transformer is suitable for low-voltage distribution networks with a small load density. Different from the single-phase isolation transformer in structure, the three-phase isolation transformer is more complex, so it is now widely used in printing and packaging, petrochemical industry, schools, shopping malls, elevators, post and telecommunications communications and a variety of industrial automation equipment and other occasions requiring normal voltage guarantee. Moreover, the three-phase isolation transformer with high quality can relieve the disturbance of the common mode and other central lines of the power grid to effectively avoid the interference and noise caused by the high-frequency pulse coupling inside the transformer, and well adapt to various complex application environments.

What factors affect the quality of toroidal transformer?

1. The high-quality core silicon steel sheet is thin, which not only has high permeability and low loss, but also has compact core winding without air gap to effectively reduce the noise of vibration induced by the core.
2. The quality of insulating material of toroidal transformer determines its safety and service life. In general, the better the insulating material is, the stronger the shock resistance is, the smaller the possibility of short circuit and leakage of toroidal transformer is, and the longer and safer the service life is.
3. The durable toroidal transformer must be coated with enamel-insulated wires and have sufficient insulation strength, uniform paint coatings and strong adhesion, so that the short circuit is rarely occur in the wound toroidal transformer.

What are the selection steps for control transformer?

1. Determine the supply and load voltages. The supply voltage is the available voltage to the control transformer. The load voltage is the operating voltage of the devices that will be connected to the transformer output.
2. Calculate the total sealed VA by adding the VA requirements of all components that will be energized together. (timers, contactors, relays, solenoids, pilot lamps, etc.) Sealed VA data is available from the control device manufacturer.
3. Add the inrush VA of all components that will be energized together. Be sure to include the sealed VA of components that don't have an inrush, (lamps, timers, etc.) as they present a load to the control transformer during maximum inrush.
4. Consider other factors. Consider other factors that may affect the control transformer's performance or installation, such as the ambient temperature, altitude, and voltage regulation requirements.

What are the benefits of autotransformer?

1. Cost-effective. Autotransformers are more economical than other transformers because they have fewer components and are smaller in size.
2. Efficient. Autotransformers are more efficient because they have fewer components and less resistance, meaning that less energy is lost as heat.
3. High voltage. Autotransformers are capable of operating with high voltage, which means that they are useful for applications where high voltage is required.
4. Space-saving. Autotransformers take up less space than other transformers, making them a good choice for applications where space is limited.
5. Simplicity. Autotransformers are simpler in design and construction, making them easier to repair and maintain.

Product Sample

Can I get samples of any transformer products at

Certainly. We offer samples, and various step up and down transformer products can be shipped worldwide. Our product management team is constantly adding new products, and we'll continue to expand the featured offerings on

How to get product samples?

Contact us via email:, tell us what specification you need and the address. Next we will deliver product(s) to you.

How many product samples can I request?

Based on the characteristics of the product, each eligible product has a maximum quantity that can be ordered free of charge. All accounts will be monitored for abuse of the sample program.

Which countries/regions can ATO ship samples to?

ATO can ship ordered samples to 62 countries/regions worldwide.

Who should I contact to discuss issues or get support?

Our customer service representatives are happy to help you place your order and help with any questions or answer any questions, including technical support for the product, inquiry, acquisition of free samples. You can contact our support team by email or phone.

What are the sample order terms and conditions?

ATO reserves the right to refuse sample orders at any time for any reason, including (but not limited to) export control regulations; concerns about abuse; excessive and/or multiple requests; multiple registrations by the same user; and /or prohibited duties/taxes/imposed import restrictions imposed by certain countries.

How can I make an enquiry?

Contact us via email: or phone number: +86 773-363-7977, and tell us what product you need. We will answer all your questions and provide you with the latest quotes.