Full-Load Speed
Full-load speed is the steady speed measured while the engine runs continuously at its rated load. On a generator it is the speed corresponding to the declared frequency; on a 4-pole alternator, 1500 rpm is required for 50 Hz. It is the lower reference point of the droop calculation.
The measurement is only meaningful under real load. The load is applied with a load bank, with the pump's real discharge condition or with the machine's normal working load; the speed is read after it has become steady. A value taken on an engine that has not warmed up is not reliable.
- If the measured full-load speed is below target, either the engine cannot produce enough torque or the throttle lever is not opening fully; the cable stroke and the upper limit setting must be checked.
- If it is above target, the load is insufficient or the measurement was taken unloaded.
The most common error in AXI installations is teaching the upper speed limit on an unloaded engine. On the GS740-3P, after the upper limit is taught with the blue wire, the potentiometer redistributes the span between idle and that limit as 0–100 percent; if the limit was taught at the wrong point, the desired speed can never be reached under load. That is why a speed test under load must be carried out after calibration.
Context in which this term is used: Electronic speed and throttle control on diesel engines