Power Hook-Up
Drum motor units are available with either a junction box or cable connection power hook-up. Junction box material construction can either be carbon steel or stainless steel (standard with all FDA/USDA approved SSVTM).

Hub Design
Two hub designs are available as standard:
Design A - the bearing hubs extend beyond the shell (refer to the technical data in the Van der Graaf catalogue)
Design B - recessed bearing hubs accommodate narrow conveyor frames while keeping the same face width.

Insulation Class
Standard Van der Graaf motors have Class F insulation that allows a motor limiting temperature of 155° C. Class H is optional which allows for a motor limiting temperature Class of 180° C. By providing a higher insulation Class, the electric motor is able to withstand a higher ambient operating temperature. The Van der Graaf drum motor has a 80°C temperature rise.

Cooling
The drum motor is designed with all vital components, such as motor and gear reducer rotating in an oil bath, sealed and isolated from the environment. Temperature generated from the motor and gear reducer is transferred through the oil to the drum/shell and dissipates on the belt.

Hermetic Sealing
The Van der Graaf drum motor incorporates high quality seals to ensure the integrity of the unit. Seals rotate on a hardened bushing to preserve seal life and extend durability. All Van der Graaf drum motors use a bolt-on design utilizing gaskets or o-rings. Wire connection paths within the unit are window stripped and epoxy impregnated to prevent any oil seepage from the motor to the junction box.

Cast Iron Components
Every Van der Graaf drum motor utilizes cast iron gear modules and motor flanges. By choosing cast iron over less expensive cast aluminum components, the Van der Graaf Drum Motor is able to withstand greater levels of belt tension over typical motorized pulley designs. This translates into an extremely durable and efficient design.

High Quality Gears
Precision AGMA 12 (American Gear Manufacturers Association) gears are high alloy steel, precision cut, hardened and honed teeth reducing noise to minimal decibel levels. Lower noise levels contribute to good working conditions and Van der Graaf units exceed OSHA low-noise requirements. As a comparison, gauge standards are typically between DIN 3-4 or AGMA 14-15.

Electric Motor
All electric motor windings are manufactured to inverter duty standards with rating of 1600v Corona Inception Voltage (C.I.V.) and Class F insulation 155°C with optional Class H insulation 180°C for applications where higher temperature operation is required.

The drum motor can be supplied with the following voltages, frequencies and phase:

This graph illustrates the typical start-up configuration and the general motor torque curves for Van der Graaf drum motors.
Motor torque is defined as follows:
1. Brake-away or starting torque
2. Minimum or "pull-up"
3. Breakdown or "pull-out"
4. Full load


All Van der Graaf motors are wound standard with inverter duty magnet wire. This wire allows for the motors to be used in conjunction with variable frequency inverters. The magnet wire itself has the ability of withstanding voltage spikes of 7,700 volts.