These parts need to be planned at the same time, but they do not have to be ordered on the same line as the motor. The pulley, coupling and base are prepared to suit the motor's shaft diameter, key size, shaft height and foot holes; so the motor model is fixed first, and the parts are then requested to that model's dimensions.

DRG-160L-6 11 kW 1000 rpm cast iron frame DRG three-phase motor – pulley, coupling and base motor order

Scope supplied by DRG

DRG's product range consists of three-phase IEC induction motors; pulleys, couplings, bases and gearboxes are not part of that range. These parts are usually sourced from the machine builder or from a power transmission equipment supplier. What matters is that both supplies are based on the same dimensional data.

What to check part by part

  • Pulley: The hub bore is machined to the shaft diameter (D) and keyway; the pulley diameter determines the machine speed. Machine speed is approximately motor speed × motor pulley diameter ÷ machine pulley diameter.
  • Coupling: Motor and machine shafts may have different diameters; the two hubs are machined separately and the coupling is chosen according to the torque to be transmitted.
  • Base: The foot hole spacing and shaft height (H) must match the driven machine. In a belt drive, slide travel is allowed on the base for belt tensioning.

Reusing the old part

The pulley of the old motor does not always fit the new one. For example, the DRG-160L-6-GG model has a 42×110 mm shaft; if your old motor's shaft is different, the hub is re-machined or a new pulley is needed. It is also important that the pulley sits fully on the shaft length: a pulley that overhangs the shaft end or sits too far out increases the load on the bearing.

Order sequence

  1. Fix the motor model and obtain its dimensioned drawing.
  2. Give this drawing to the pulley, coupling and base fabricator.
  3. For belt drives, check the pulley diameters with the pulley and belt calculation tool.

Shaft and key standards are explained in detail in the article on shaft diameter, keys and couplings. You can choose the model whose dimensions you will work from in the online motor store.