Secondary voltage
The output voltage delivered to your installation (U2).
Definition
The secondary voltage is the voltage delivered by the transformer to its load — the output voltage, denoted U2. It is the sizing parameter for powering your equipment: each load (motor, drive, controller, lighting, etc.) requires a rated voltage that the transformer must supply accurately.
The no-load secondary voltage (U20) is slightly higher than the voltage at rated load, because the internal voltage drop (related to impedance) is not yet present. The gap between U20 and rated U2 is defined by the transformer’s voltage regulation, expressed as a percentage.
For SELV (Safety Extra-Low Voltage) networks, typical secondary voltages are 12 V, 24 V or 48 V. For industrial distribution, 230 V, 400 V or 690 V are found at the output.
The ABL tip
When requesting a quote, state the secondary voltage required under rated load (not no-load). If your installation includes long distribution cables, a slight no-load overvoltage can help compensate for line drops. Our engineers calculate this automatically.
