Output voltage

The output voltage of a transformer is the electrical voltage that is available on the secondary side of the transformer. It results from the ratio of the number of turns between the primary and secondary windings and is decisive for the supply to the connected loads.

Technical basics

A transformer works on the principle of electromagnetic induction. The voltage is transferred from one winding to another without mechanical movement

Typical output voltages

A distinction is made depending on the application:

• Low voltage (e.g. 12 V, 24 V, 230 V): for household appliances, lighting, electronics
• Medium voltage (e.g. 10 kV, 20 kV): for industrial applications and grid distribution
• High voltage (e.g. 110 kV, 400 kV): for transmission grids

Influencing factors

1. Winding ratio: The more windings on the secondary side compared to the primary side, the higher the output voltage.
2. Load: The output voltage may drop slightly under load (voltage drop).
3. Regulation: Some transformers have voltage regulation (e.g. tap changer).
4. Frequency: The output voltage also depends on the frequency of the input current (e.g. 50 Hz in Europe).

Safety and standards

• Tolerances: The output voltage may only fluctuate within certain limits (e.g. ±10 %).
• Insulation requirements: Higher output voltages require stronger insulation.

Protective measures: Surge protection, earthing and fuses are essential.