An isolation transformer is a type of transformer that is used to isolate two electrical circuits from each other. It does this by using a primary winding and a secondary winding that are not physically or electrically connected to each other. Instead, the transformer relies on magnetic coupling to transfer electrical energy from the primary to the secondary winding.
Isolation transformers are designed to have a 1:1 turns ratio, which means that the number of turns on the primary winding is equal to the number of turns on the secondary winding. This means that the voltage and current levels on the primary and secondary sides are also equal. Because of this, isolation transformers are sometimes referred to as 1:1 ratio transformers.
Isolation transformers are used for a variety of purposes, including providing electrical isolation between electronic circuits and protecting people from electrical shock. They are often used in situations where it is necessary to isolate electrical equipment from the power source, such as in wet or damp environments or when working with earthed metal surfaces. Isolation transformers are also used in transmission and distribution systems to step up or step down voltage levels.
It is designed to reduce voltage spikes and eliminate ground loop interference in the electrical power supply lines.
One of the main functions of an isolation transformer is to protect electrical equipment from voltage spikes. These are sudden, short-duration increases in voltage that can be harmful to electrical equipment and cause interruptions in service. When a voltage spike occurs on the primary side of the isolation transformer, the inductive nature of the transformer's primary winding opposes the sudden change in current, reducing the spike before it reaches the load. This helps to protect sensitive equipment, such as medical devices or laboratory equipment, from damage.
In addition to reducing voltage spikes, an isolation transformer can also eliminate ground loop interference and noise effects on the load. Ground loop interference occurs when there is a difference in ground potential between two electrical circuits, causing noise and interference in the signal being transmitted. An isolation transformer eliminates this interference by isolating the primary and secondary circuits, preventing the flow of current between them.
The construction of an isolation transformer is similar to that of a normal core-type transformer, but it includes electrostatic shields that suppress noise and completely isolate the secondary from the primary. An autotransformer, which has a common winding for both the primary and secondary circuits, cannot be used as an isolation transformer because it has an electrical connection between the two windings.
In the example you provided, the electric concrete mixer was causing electric shocks to the user because it had an earth leakage problem. An earth leakage problem occurs when there is a fault in the electrical wiring of the equipment, allowing electricity to flow through the equipment and potentially shock the user. By using an isolation transformer, the hire company was able to protect the user from electric shock by creating a barrier between the mixer and the power source. This allowed the user to safely use the mixer without being at risk of electric shock.