Conveyor running power describes one established operating point. Starting requires the motor to release static resistance, control belt tension and accelerate the combined inertia before its allowable start time is exhausted.
Build the load case from the conveyor
Request running resistance, breakaway torque, retained material load, belt slope, take-up arrangement, backstop behaviour and the required starts from cold and hot conditions. Define whether the operating procedure clears the belt after a trip or demands a loaded restart.
Plot torque margin through acceleration
Acceleration torque = available motor torque − conveyor load torque
Positive torque margin is required throughout the run-up. The acceleration time follows from that margin and the combined inertia referred to the motor shaft. A high locked-rotor torque does not guarantee adequate torque near pull-up speed.
| Case | Main question | Evidence required |
|---|---|---|
| Empty start | Can friction and inertia be overcome? | Empty-belt resistance and inertia |
| Loaded start | Can retained material move without excessive tension? | Loaded torque curve and belt calculation |
| Reduced-voltage start | Is torque still adequate at actual terminal voltage? | Network study and motor torque curve |
| VFD start | Are current limit and low-speed cooling sufficient? | Motor-drive torque envelope |
| Multi-drive start | Will drives share torque without belt shock? | Control sequence and load-sharing method |
Include voltage and thermal limits
Starting current can depress the motor-terminal voltage. Induction-motor torque is strongly affected by voltage, so evaluate the torque curve at the predicted starting voltage rather than only at rated supply.
Repeated unsuccessful starts consume thermal capacity. Define permissible cold and hot starts, restart delay and stall protection from the offered design and starting study.
Treat backstops and brakes as functional interfaces
On inclined conveyors, trapped load can act before positive motor torque is established. Review backstop release, brake timing and rollback prevention with the conveyor supplier. The motor vendor cannot infer these mechanics from rated kW.
Information for a defensible quotation
Send belt speed, lift, capacity, material condition, starting load case, load torque curve, total inertia, supply study, starter or VFD method, ambient and duty. LEADGO can then compare induction, high-voltage and PM drive options on the same acceleration boundary.