Isolation transformer

Isolation transformer

An isolation transformer is a type of transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source, usually for safety reasons. Isolation transformers provide galvanic isolation, which is the principle of isolating different sections of electrical systems to prevent current flow; no direct conduction path is permitted. Energy is transferred by induction from the transformer's primary to secondary winding.

The primary reasons for using an isolation transformer include protection against electric shocks, minimizing the transfer of electrical noise and disturbances from the power supply to sensitive devices, and the safe isolation of a device from the main power source for servicing or maintenance.

Design and Function

Isolation transformers are designed with a 1:1 winding ratio between the primary and secondary coils. This means that the voltage applied to the primary winding is the same as the output voltage from the secondary winding, assuming the transformer is ideal and there is no loss. However, transformers can be designed with different winding ratios to step up or step down voltages as required for specific applications, but in the context of isolation, the focus is typically on 1:1 transformers.

The core of an isolation transformer is usually made of high-quality, laminated silicon steel to minimize energy losses. The primary and secondary windings are physically separated and often have additional insulation to enhance safety and isolation capabilities.

Applications

Isolation transformers are widely used in various applications where isolation is required for safety or technical reasons. Some common applications include:

• Medical equipment: To ensure the safety of patients and medical personnel by isolating medical devices from the main power supply.
• Audio equipment: To eliminate hum and noise caused by ground loops.
• Sensitive electronics: To protect against voltage spikes, surges, and other disturbances that might originate from the power supply.
• Laboratory equipment: To provide a safe working environment by isolating equipment from potential electrical hazards.

Safety Considerations

While isolation transformers significantly improve safety by isolating the secondary circuit, it's important to note that the output side is still potentially dangerous if mishandled. Proper grounding, circuit protection devices, and adherence to safety standards and regulations are essential when using and installing these transformers.

Conclusion

Isolation transformers play a crucial role in enhancing electrical safety and protecting sensitive devices from potential damage caused by electrical noise, surges, and other disturbances. Their ability to provide galvanic isolation makes them an essential component in various applications, from medical and audio equipment to sensitive electronics and laboratory instruments.

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  Isolation transformer

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  Isolation transformer with dielectric barrier and electrostatic shield

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  Impulse transformers TG110 top and bottom view