DRUM MOTOR OPTIONAL FEATURES 

All Stainless Steel 
All units are available in all stainless steel construction, including end caps, shell, shafts and junction box. 

Non-Standard Length / Extra Long Face Width 
Many combinations are available, please contact your Van der Graaf technical representative for details. 

GV Thermal Overload Protection (GVTHERM) 
Thermal overload protectors are devices, imbedded into the motor windings (one per phase) and are available for both Class F and H insulation. These protectors are a bi-metal type, maintaining continuity under normal temperature conditions. 

When temperature within the motor rises above 135°C for Class F and 165°C for Class H, the GVTHERM will function, causing an open circuit between the respective GVTHERM leads (yellow). 

For their proper operation, it is necessary to wire the GVTHERM leads to the motor starter. Connecting the two GVTHERM leads in series with the coil of the electromagnetic contactor will result in power interruption to the motor, when motor temperature exceeds 135°C for Class F and 165°C for Class H, thus protecting the motor from thermal overload. 

"No Belt" (NB) Operation 
No Belt design series drum motor is mandatory for applications without a full belt contact to the drum motor or using modular belt which do not have the ability to dissipate the heat generated by the drum motor. The NB series drum motor should be specified when: 
a) the conveyor belt covers less than two thirds of the overall face width 
b) modular sprockets are attached to power modular belting 
c) no conveyor belt is used 
Please contact your Van der Graaf representative for application assistance. 

V Grooves 
V-grooves are available on all Van der Graaf drum motors. The v-groove is machined into the shell for optimal tracking and single or multiple v-groove locations are available. If lagging is required then a 1/8" maximum thickness is available to minimize chance of v-guide climb out. 

Shell Crowns & Finishes Machine crowned (convex) shell tracks on all points of contact maximizing belt traction and extending belt life. Drum Motors are available in the following shell finishes:

Lagging 
Van der Graaf offers a complete line of 'hot bond' and urethane laggings. Hot Bond lagging, better known as vulcanization actually cures rubber, wrapped to the desire thickness around the shell of the drum motor, under high-pressure and high-temperature. The result is a seamless, durable and tear resistant lagging. Urethane lagging is a two part ribbon flow cast method which pours liquid urethane directly on the shell. The shell finish prior to urethane lagging is prepared by a patented spiral groove to aid in adhering the urethane to the shell. Various finishes are available including smooth, herringbone, diamond, chevron, and user specific. As standard, all white finishes are ground smooth to avoid any type of product contamination. 

A variety of finishes are available in 1/8", 3/16" 1/4", 3/8", 1/2", 3/4" and 1" thickness. Non-standard thickness requirements are available upon request.

Class H Insulation 
For motor limiting temperature Class of 180°C. By providing a higher insulation Class, the electic motor is able to withstand a higher ambient operating temperature.