Glossary · Motion control and drives
Four-quadrant operation
Also known as: Four-quadrant drive
German: Vierquadrantenbetrieb
In electric drives, four-quadrant operation is the ability of a drive to motor and to brake in both directions of rotation, covering all four combinations of torque and speed sign in the torque–speed plane.
- Motion control
In one sentence
Four-quadrant operation means a drive can motor and brake in both directions, covering all combinations of torque and speed sign.
Example
A hoist drive works in four quadrants: it lifts and lowers loads and brakes them in both directions.
How it applies
- Engineering: In quadrants II and IV the motor works as a generator. The braking energy must go somewhere: into a braking resistor, a shared DC bus or back to the grid (Regenerative drive).
- Commissioning: Braking resistor sizing and the drive's overvoltage behavior are tested with the real load, including emergency deceleration.
- Operation: If braking energy can't be absorbed, the drive trips on overvoltage and the axis may coast, which lengthens the Stopping time.
- Documentation: Show the quadrant diagram when explaining braking options. Warn that braking resistors get hot, and state required clearances and inspection intervals.
Four-quadrant vs. regenerative
Four-quadrant describes the operating range (motoring and braking both ways). Regenerative describes where braking energy goes (back to the supply). A four-quadrant drive can dissipate braking energy in a resistor without being regenerative.