ComTrac® Adjustable Speed Drives
Selection

In general, proper selection of a ComTrac drive is as easy as the drive is to operate.

1. Establish the maximum horsepower required by the driven machine at maximum speed.
2. Select the drive which meets or exceeds the maximum HP rating of the driven machine at maximum speed.

Operation
Because of its mechanical operation, the ComTrac drive generally produces constant output torque, while the induction motor produces constant horsepower and constant speed, the two are combined in a manner that provides optimum utility and economy.

The ComTrac drive has two operating regions.

• Constant torque between the drive's absolute minimum speed and transition speed.
• Constant horsepower between the transition speed and the maximum speed.

When selecting a ComTrac drive, it is important to choose a unit which will not allow the cone and ring system to be over powered by the motor. As shown in the ComTrac Performance Chart, ComTrac drives should always be selected so that the output torque required is well below the torque capability of the cone and ring system.

General Selection Considerations
The ComTrac drives shown in the selection tables are rated for constant torque operation - where required horsepower varies directly in proportion to the speed of the driven machine.

In general, proper selection of a ComTrac drive begins by establishing the maximum horsepower required by the driven machine at maximum speed. A ComTrac drive is then selected with a maximum speed and horsepower rating that meets or exceeds that of the driven machine. Since the typical ComTrac application requires constant torque over the entire speed range, there will be an adquate service factor to protect the traction ring from damage.

Non-Standard Application Conditions
For constant horsepower applications, or any of the non-standard application conditions shown below, please contact the STOBER Technical Support group for ComTrac Selection.

Unusual Loading Conditions

• Heavy shock loading
• High inertia loads
• Load reversals or overhauling loads
• More than ten starts per hour

Unusual Environmental Conditions

• High altitudes - above 5000 feet
• Explosives fumes or corrosive chemicals
• Excessively dusty or abrasive environments
• Ambient temperatures below 25 degrees fahrenheit or above 125 degrees ferenheit

Non-Standard Motors

• Motor frame sizes other than those shown in the selection tables in the catalog.
• Motors other than NEMA Design B

Non-Standard Mounting

• Shaft up or shaft down vertical mounting

Application-Matched Options
Several Options for ComTrac Drives such as washdown duty, remote speed controls, etc. are avaliable. In addition the following options and others are also avaliable:

• 50 Hz Operation for export
• Various Motor Enclosures

For application and selection assistance, for these options and more, contact your local STOBER Drives distributors.

Part No. Example:

TD47	0	F	K182	W
Traction Drive Model/Size	0 – Non geared	F – Flange Mount	Input for NEMA Frame Size (182TC)	Washdown/Severe Duty (Option)

TD47	0	N	K182	W
Traction Drive Model/Size	0 – Non geared	N– Foot Mount	Input for NEMA Frame Size (182TC)	Washdown/Severe Duty (Option)