Dynamic Braking Resistors control the speed or stop AC and DC motors. When power is cut, the motor rotates due to kinetic energy, feeding back into the drive. This prolongs stopping time and can cause overvoltage faults at the DC drive terminal. A suitable resistor prevents these issues.
The resistor made of stainless steel wire is placed in an aluminum case with a larger surface which allows good heat dissipation. The space between the resistor and the case is filled with a isolation powder which have high thermal conductivity and electrical insulation. Resistors manufactured using this technology can be used as braking resistors or capacitor discharge resistors, load tester, wind power plants, hybrid vehicles and other industrial applications.
Standard resistors are 1-meter long, with fiber glass braided silicone cables suitable to rated current and cable connections resistant to high temperature. They can be manufactured with connectors or terminals on request
Aluminium Braking Resistors - BRA
Advantages
- Compact sizing, option to use without a cabinet,
- High protection degree against humidity, dust, solvents and water splash
- Excellent mechanical impact and vibration withstand
- Efficient design to ensure long life time with an internal structure for high heat transmission and external structure facilitating heat transmission
Application Areas
- Elevators
- Escalators
- Cranes (Tower, Gantry, Travelling Cranes)
- Work Platforms, Construction Hoists, etc.
- Mines (in wagons, for mixing, stone crunching, etc.)
- Automation (cable, wire, and some textile factories)
Frame Braking Resistors - BRS, BRE, BRG
Advantages
- Compact and elegant frames with high cooling performance designed for high power loads
- All connector elements are manufactured of non-corrosive materials.
- Special structure resistant
- To ensure protection degree from all direction, the bottom part of the frame is also closed and ventilated
Application Areas
- Cranes (Tower, Gantry, Travelling Cranes)
- Work Platforms, Construction Hoists, etc.
- Mines (in wagons, for mixing, stone crunching, etc.)
- Traction Power
- Marine & Harbors
Aluminium Braking Resistors - BRA
Technical Specifications
- Maximum Operating Voltage : 1000 V
- Resistance Tolerance @ 20°C : ± 5%
- Protection Class : IP5X (Indoor)
- Insulation : 2 kV, 50 / 60 Hz, 1 min
Standards
- IEC 60664-1
- IEC 60529
Frame Braking Resistors - BRS, BRE, BRG
Technical Specifications
- Maximum Operating Voltage : 1000 V
- Resistance Tolerance @ 20°C : ± 5%
- Protection Class : IP20 (Indoor), IP23 (Outdoor)
- Insulation : 3 kV, 50 / 60 Hz, 1 min
| Type | Size | Download Link | |
| BR - Braking Resistors | 1 MB | Download |
What is VFD braking resistor?
VFD braking resistors are used in order to ensure fast stopping or decrease the speed of AC and DC electric motors controlled by speed drives (speed control devices). Due to kinetic energy, an electric motor continues to rotate for a short time even after it has been switched off. As the rotor keeps rotating, the motor starts acting as a generator and feeding the drive. This may not only increase the stopping time of the motor, but also cause a voltage increase on DC drive’s terminal leading to an over voltage fault and consequently a shut down. In order to avoid such problems, a breaking resistor of a proper resistance value and rated power should be connected to the DC drive’s terminal.
What is a braking resistor used for?
Braking Resistors are used in many motor applications that is controlled with driver. One of the most common application is vertical and horizontal movements of fixed cranes, portal bridge cranes, overhead travelling cranes and tower cranes. Braking resistors are used for travelling facade platforms used for construction and maintenance of buildings, facade hoists and personnel elevators, cradle systems and facade cleaning systems. Some of other applications which braking resistor used are lifts and elevators controlled by a driver and operated by a synchronous (geared) and asynchronous (gearless) motors, machinery and presses where heavy loads are moved instantly, railway vehicles and hybrid or electrical road vehicles.
How to use braking resistor?
When the motor works as a generator, voltage increases on DC drive’s terminal leading to an over voltage fault and consequently a shut down. The braking resistor of a proper resistance value and rated power should be connected to the DC drive’s terminal. The braking resistor converts the energy released during stopping into heat energy.
How to size a braking resistor?
Resistance value of the braking resistor changes based on the drive. This can be detected by the driver's manufacturer. This value is specified in the drive's user guide. If this value is given as Rmin and Rmax, the resistance should be close to Rmin and but not lower than Rmin. Braking time extends as it gets closer to Rmax. The resistance power is determined based on the application used by the motor to which the drive is connected. It can be determined with special engineering calculations or specified by the company based on our experience on frequently used applications. In some cases, the power of resistance can be equal to the motor power, or even up to ten times smaller than it.
