The basic calculation is the power needed to raise the material conveyed per hour to the lift height; on top of this come the resistance the buckets meet as they dig material in the boot section, belt or chain losses, and a margin for starting when loaded. The motor sits at the elevator head and usually drives the head pulley through a gearbox or a belt.

DRG-132M2-6 5.5 kW 1000 rpm DRG three-phase motor with aluminium frame – bucket elevator motor selection

Data that go into the calculation

  • Hourly capacity (t/h) and the bulk density of the material
  • Height between the boot and the head
  • Bucket volume, spacing, fill ratio and belt speed
  • Feeding method: buckets digging the material from below, or material poured directly into the buckets
  • Whether a belt or a chain is used

Lifting power is found roughly from capacity × height; digging and friction losses are added to this. Exact allowance factors should be taken from the elevator manufacturer's data.

Loaded restart and runback

When the power fails, the loaded buckets on the up side tend to turn the elevator backwards; material spills into the boot and the boot is full at the next start. This is why elevators use a backstop and why starting torque is particularly important in motor selection. The backstop is mounted on the gearbox or the head shaft; it is not a feature of the motor itself.

Speed and drive

The head pulley turns at low speed, so a 1500 rpm motor is used with a gearbox or a pulley arrangement. Since belt speed is important for centrifugal discharge, the output speed must be calculated correctly; the gearbox output speed and torque calculator can help with this. DRG does not sell gearboxes; the motor is chosen to suit the input conditions of the selected gearbox.

Environment and application pages

In grain and flour elevators, fine dust collects on the motor's outer surface and reduces cooling; areas classified as explosive dust zones require certified products, and such motors are not in the DRG range. Application examples are on the flour mill elevator motors and agricultural elevator motors pages.