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Video: What Is The Braking Resistor?
2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-05-24 11:12
An electric motor that moves a milling machine, for example, receives the electricity it needs from the network (alternating current). There is usually a frequency converter between the mains and the motor, which rectifies the alternating current and converts it back into alternating current as required. The area in between is called the DC link (see circuit diagram).
If the milling machine is to stop or change direction, the frequency converter throttles its frequency. The engine continues to work and becomes a generator - kinetic is converted into electrical energy.
The current generated in this way is now returned to the frequency converter, which then reduces the current consumption from the network. However, since the current consumption from the network cannot be reduced to the same extent as the current drawn from the motor, the voltage in the DC link increases.
This is exactly when the braking resistor comes into play. It is used to chop the DC voltage, chopped up by an electrical switch ("chopper"), to remove the excess voltage from the DC link to ensure the safety of the entire system. This creates heat that has to be dissipated, which places high demands on the design and material of the resistor.
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