Glossary · Electrical engineering and control panels
Uninterruptible power supply (UPS)
Also known as: UPS
German: Unterbrechungsfreie Stromversorgung (USV)
In electrical engineering, an uninterruptible power supply (UPS) is a system with energy storage, usually batteries or capacitors, that continues to supply connected loads during interruptions or disturbances of the mains supply for a defined time.
- Control panels
In one sentence
A UPS keeps loads supplied from batteries or capacitors during mains outages for a defined time.
Example
A DC UPS keeps the PLC and industrial PC running for two minutes after a power failure, long enough to save data and shut down in a controlled way.
How it applies
- Engineering: AC UPS systems follow the IEC 62040 series; DC UPS modules on the DIN rail are common for 24 V control circuits. Define which loads are backed up, for how long, and what the controller does on a power-fail signal, such as controlled shutdown or data saving.
- Safety and maintenance: A UPS keeps circuits live after the mains is disconnected. Isolation procedures must include the UPS as an energy source, like other Stored energy.
- Documentation: Describe backed-up circuits, bridging time, battery replacement intervals and the isolation procedure. Place labels in the cabinet indicating that circuits are UPS-supplied.
UPS vs. buffer module
A buffer module bridges very short interruptions, typically milliseconds to seconds, often with capacitors. A UPS bridges longer outages with batteries and often signals its state to the controller.