Resistance Boxes, buy Dynamic Braking Resistors on China Suppliers Mobile

Product Details

Specifications

1-Efficient distribution of Power
2-Sturdy components
3-Long, trouble free service

Resistance Boxes are used to add resistance into an electric motor circuit for modifying the performance characteristic of slipring induction motors of EOT cranes, rubber mills, steel rolling mills, cement mills, power plants, conveyors, coke oven, blowers etc. or speed control and developing starting torque with low starting currents. They are also used as Dynamic breaking resistor for V.V.F.A.C. Drives, electric loading of ac alternators, de generators and dynamometers. Resistors are designed to meet requirements of both A. C. & D. C. Applications.

Types of Resistors :

Punched Grid Resistors (Stainless Steel/Feehral)
Stainless steel wire grid resistors

Types of Cooling :

Air cooled type
Oil cooled type

Braking resistor for frequency Converters

Braking Resistors are used in the d. c. Link of the frequency converter. A braking chopper activates the resistor. If the output frequency of the frequency converter drops -be it by a control process, a drop in speed or a braking operation-below the current operating frequency of the motor, the motor takes on the function of a generator. The consequence is arise in the link voltage. If this voltage exceeds the specific value of the unit in question, chopper will activate the braking resistor. If the voltage drops to a value just above the grid voltage of the link, the chopper will interrupt the circuit. This process will be repeated until the motor speed once again matches the applied operating frequency. The braking resistor takes on the energy and converts it into heat.

Braking resistor operating modes

Braking resistors are usually only activated for a short time, save the braking energy and give off the stored heat to the environment during the breaks when they are inactive. This is intermittent operation with a cyclic duration factor ( c.d.f ) indicated in % of the duty cycle time. The duty cycle time tsp is calculated from the total of the braking time ta plus resting time tr. The overload capacity of the resistors is dependent on the thermal time constant and thus on the design, among others.

Product Portfolio :

Available with us is a praiseworthy range of Crane Control Gears that is suitable for use in varied industry applications. Manufactured using high grade raw material, these control gears are assured to feature a longer functional life. As these are based on latest technology, it is proved that their performance will be reliable and efficiency unquestioned. Hosting such beneficial features, these products are demanded across the globe on a large scale.

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