Resistance Boxes

“STERLING” Grid type Resistance Boxes are usually used with slip-ring [Wound Rotor] Motors [AC and DC] to provide control of starting torque, starting current and speed. They are designed to meet different classes of service, in various applications where slip-ring motors are used such as Conveyors, Screws Feeders, Steel Rolling Mills, Rubber Mills, Cranes, Hallagues, and Compressors etc. Desired control operation of Slip-ring Motors is obtained through external connections of appropriate values of Resistance into the Rotor slip-ring circuits. Slip-ring [Wound Rotor] Motors can operate with an infinite number of different speed, torque or current characteristics. Different performance criteria are obtained by the selection of external resistance which is connected into the slip-Ring circuit.

“STERLING” Grid type Resistors are custom designed and manufactured to suit customers specific requirements, whether for starting duty or for continuous-speed-duty operations, in accordance with relevant BSS, NEMA or IS specifications.

Rating / Duty Cycle 

The Resistances are designed and manufactured to suit rating and duty cycles as required by the customer in his application and temperature rise does not exceed the limit specified in BSS 587-1957.

Operation

“STERLING” Resistances may be operated through Drum Controllers or by Master Controllers with associated contractor gear or with Timers and contractors in Slip-ring Motor starter panels.

Construction

“STERLING” Resistance Boxes Manufacturer are assembled with stainless steel wire grid type or punched stainless steel type elements, which are restless, unbreakable, and capable of withstanding mechanical shocks and vibration. The grids are mounted on high tensile steel rods insulated with heat resistant Mica tubes. These assemblies are mounted in well ventilated sheet steel housings, ensuring low temperature rise. All Resistance steps are terminated on a common terminal strip which facilitates installation and wiring.

Ordering Information

While ordering STERLING Resistance Boxes the following information is requested which will enable us to provide you with the most suitable offer?

1. Application details
2. Supply: AC/DC
3. Motor HP/KW
4. Rotor Voltage and Rotor Current
5. Starting Torque required
6. Number of steps required
7. Whether operated through Drum Controller or Master Controller / Contractors
8. Any other specific requirements

OTHER PRODUCTS

• Flexible Brake Drum & Brake Drum Couplings.
• Full Geared & Half Geared Couplings.
• Geared Brake Drum Couplings.
• Carbon Brushes
• Punched Grids
• Spare Coils for EM Brakes.
• Brake Liners & Brake Shoes.
• Cable Carriers & Trolleys.
• Clutches & Disc Brakes
• Current Collectors & Spares

 “STERLING” Engineers will be pleased to assist in the selection of this item in special requirements and applications.