# Synchronous condenser Canonical URL: https://eloragrid.ai/symbols/synchronous-condenser Publisher: Elora Grid Updated: 2026-10-28 Lookup label: SC Drawing use: SLD Reference families: IEC, IEEE / ANSI An unloaded synchronous machine on the network that supplies reactive power, inertia and short-circuit strength. ## In plain English ### What does Synchronous condenser mean? A synchronous condenser is a synchronous machine running without a prime mover, connected to the network to supply or absorb reactive power by adjusting its field current. Because it is a real rotating machine it also contributes inertia and high short-circuit current, which converter-dominated networks often lack. ### A simple example Single-line diagrams draw a synchronous machine circle labelled SC or with a capacitor-like note, connected through a step-up transformer and breaker, with a starting arrangement such as a pony motor or static frequency converter. A flywheel may be shown on the shaft to add inertia. ### What the drawings help you do The symbol looks like a generator but the machine exports no active power and draws a small amount to cover losses. It does not show the starting method, inertia constant or overexcitation limits, which define how much it helps during faults. ### This particular reference An unloaded synchronous machine on the network that supplies reactive power, inertia and short-circuit strength. A synchronous condenser exchanges only reactive power; a synchronous generator also delivers active power from a prime mover. ### Terms - Winding: A coil of conductor inside an electrical machine or transformer. - Normally open / normally closed: The contact state in the normal condition defined for the drawing. - Rating: A value stating the conditions for which equipment is specified. 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. - [Synchronous Condenser System](https://www.hitachienergy.com/products-and-solutions/facts/synchronous-condenser-system) - [Generator symbol variants](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-09BE3BB5-9118-4302-8061-3888692E538F.htm) ## What it represents A synchronous condenser is a synchronous machine running without a prime mover, connected to the network to supply or absorb reactive power by adjusting its field current. Because it is a real rotating machine it also contributes inertia and high short-circuit current, which converter-dominated networks often lack. Single-line diagrams draw a synchronous machine circle labelled SC or with a capacitor-like note, connected through a step-up transformer and breaker, with a starting arrangement such as a pony motor or static frequency converter. A flywheel may be shown on the shaft to add inertia. The symbol looks like a generator but the machine exports no active power and draws a small amount to cover losses. It does not show the starting method, inertia constant or overexcitation limits, which define how much it helps during faults. ## How to read it - There is no prime mover; a pony motor or static starter is used only to bring the machine up to speed. - Check for a flywheel added to raise inertia. ## Information to show or reference - State Mvar range, inertia and short-circuit contribution. - Show transformer and starting method. - Reference excitation limits. ## Important distinction A synchronous condenser exchanges only reactive power; a synchronous generator also delivers active power from a prime mover. ## Facts - Machine: Synchronous, no prime mover - Services: Reactive power, inertia, short-circuit strength - Starting: Pony motor or static starter - Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic ## Public references - [Synchronous Condenser System](https://www.hitachienergy.com/products-and-solutions/facts/synchronous-condenser-system) — Hitachi Energy. Public synchronous condenser system page. - [Generator symbol variants](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-09BE3BB5-9118-4302-8061-3888692E538F.htm) — Autodesk. Public synchronous machine symbol family 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.