Resistance Boxes

Resistance Boxes


Controlling motors with resistors is a universal method of speed control. The resistors are used to limit the in-rush current and adjust the torque and speed characteristics of an ac and dc motor

By changing the resistant on the rotor (through contactor), you can limit the starting torque and speed of the motor for your specific application.

SPEEDAGE  make Resistors are designed to meet requirements of A.C & D.C. application for E.O.T. Cranes, Winches, Rubber Mills, Flour Mills, Coal Mines, Cement Mills, Power Plants, Conveyors, Coke Oven, Blowers etc. for Speed control and developing Starting Torque.

The specification comply with BSS 587: 1957


• overhung top with canopy to prevent standing water and will support heavy ice and snow.
• Forged eyebolts are provided in all four corners for easy handling.
• Removable front and rear louvered covers for easy access for connection and inspection.
• Corrosion resistant nameplate provides complete ratings and manufacturer's information.
• Galvanized Iron Sheet provides maximum protection.


• Aluminum, mill galvanized, stainless steel and hot-dipped galvanized construction.

  Custom paint finish is also available.
• Top or side mounted entrance bushing(s).
• Screened covers for indoor applications.
• Support stands for elevating the enclosure above ground.

Stainless Steel Wire Grid type Resistors
Stainless Steel Punched Grid type Resistors

These are designed and manufactured for current ratings form 10 Amps. to 234 Amps. Continuous Resistors of higher ratings are manufactured by using 2 or more parallel paths. Resistors with short time ratings up to 3000 Amps. or even more for neutral grounding are possible which are suitable for system voltage up to 11 KV and above

Resistors can be designed to BSS / VDE/NEMA/IEEE or any other requirement specified by customer. The Temperature rise for stainless steel wire and Punched steel grids is 375*C. Resistors can also be supplied for lower temperature rise such as 220*C etc. by suitably de-rating the grids. Resistors for higher temperature rise can also be designed for short time duty e.g. 760* C for stainless steel which is permitted by IEEE Standard 32