# Rotary UPS

Canonical URL: https://eloragrid.ai/symbols/rotary-ups
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: RUPS
Drawing use: SLD
Reference families: IEC, IEEE / ANSI

A UPS built around a rotating synchronous machine with kinetic storage, often coupled to a diesel engine for long backup.

## In plain English

### What does Rotary UPS mean?

A rotary UPS uses a synchronous machine running continuously on the critical bus, with stored kinetic energy in a flywheel or induction coupling bridging the gap until a coupled diesel engine starts and takes over. A choke between the utility and the critical bus lets the machine condition the supply and isolate the load from network faults.

### A simple example

Single-line diagrams show the incoming utility feeder, a series choke, the synchronous machine with its kinetic energy module and clutch to the engine, and the critical and sometimes non-critical outputs. A bypass path around the unit is normally drawn.

### What the drawings help you do

The machine provides real short-circuit current, unlike a static UPS, which helps downstream protection discriminate. The symbol does not show the ride-through time to engine pickup or the choke impedance, both of which matter for design.

### This particular reference

A UPS built around a rotating synchronous machine with kinetic storage, often coupled to a diesel engine for long backup. A rotary UPS uses rotating machines and kinetic storage; a static UPS uses power electronics and a battery.

### Terms

- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Rating: A value stating the conditions for which equipment is specified.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [DC UPS, AC UPS and capacitor buffer modules](https://www.phoenixcontact.com/en-gb/products/uninterruptible-power-supplies-ups)
- [T-030 liquid-cooled generator set application manual](https://www.cummins.com/sites/default/files/2024-08/t030-Liquid-cooled-gen-set-application-manual.pdf)


## What it represents

A rotary UPS uses a synchronous machine running continuously on the critical bus, with stored kinetic energy in a flywheel or induction coupling bridging the gap until a coupled diesel engine starts and takes over. A choke between the utility and the critical bus lets the machine condition the supply and isolate the load from network faults.
Single-line diagrams show the incoming utility feeder, a series choke, the synchronous machine with its kinetic energy module and clutch to the engine, and the critical and sometimes non-critical outputs. A bypass path around the unit is normally drawn.
The machine provides real short-circuit current, unlike a static UPS, which helps downstream protection discriminate. The symbol does not show the ride-through time to engine pickup or the choke impedance, both of which matter for design.

## How to read it

- Identify the choke between the utility and critical bus.
- Check engine coupling and the kinetic module.

## Information to show or reference

- State machine rating and ride-through time.
- Show choke, engine coupling and bypass.
- Reference fault current contribution.

## Important distinction

A rotary UPS uses rotating machines and kinetic storage; a static UPS uses power electronics and a battery.

## Facts

- Energy store: Kinetic, flywheel or induction coupling
- Long backup: Coupled diesel engine
- Fault current: Machine-sourced
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [DC UPS, AC UPS and capacitor buffer modules](https://www.phoenixcontact.com/en-gb/products/uninterruptible-power-supplies-ups) — Phoenix Contact. Public UPS function context.
- [T-030 liquid-cooled generator set application manual](https://www.cummins.com/sites/default/files/2024-08/t030-Liquid-cooled-gen-set-application-manual.pdf) — Cummins. Public engine-generator application context.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.