A drummotor is a fully closed electric motor. Primarily the drummotor has been developed to drive conveyor belts, but beltless applications are also possible. By fitting sprockets modular belts can also be driven and drummotors fitted with external brushes have been used for cleaning purposes. It is also possible to design a drummotor to be used as an electrical generator.
The electric motor, gears and bearings are placed inside the drum ensuring a compact construction. High performance sealing are used to prevent oil leakage and the ingress of water and dust. Different sealing types have been developed for different situations e.g ip68 underwater sealing. with a minimum ip rating of ip66, water and dust have no chance of entering the drummotor. The oil in the drummotor is used not only to lubricate the gears but also to keep the electric motor cool. The shell has a barrel crowned finish to aid belt tracking.
All gears are made of high alloyed hardened steel; Low noise level and longevity are ensured by machining the gear teeth to fine tolerances and finishing by polishing or honing. Ball and needle bearings are oversized. The power is connected directly to the stator (standard insulation class F). There is no need for slip rings or brushes .
End caps are firmly attached to the shell with bolts. This design makes dismantling the drummotor very easy. Oil can be changed or checked without removing the drummotor from the conveyor (subject to frame design). Drummotors are fitted as standard with a terminal box, which can be rotated right or left by max 90° to assist in the cable entry.
All drummotors are designed according to IEC standard, protection class IP 66. The speed of the drummotor can be adjusted by using an inverter. Dahlander (multi-pole winding) drummotors can be manufactured to allow 2 speed operation. "GV" drummotors can be manufactured according to CSA, UL or Atex standards on request. Complete or part use of stainless steel (304 or 316) is also possible. All drummotors are provided with a CE marked data plate. Special sealing for more extreme conditions are optional e.g IP68 (underwater).
Van der Graaf also manufactures taildrums and mounting brackets to fit the drummotors.