How to match inverter brake resistors of different powers?

The inverter brake resistor is a device set up during the operation of the inverter to achieve the rapid stop of the motor. Its main function is to consume the inertial energy of the motor and quickly reduce the motor speed to zero, thereby achieving the rapid stop of the motor. However, since motors of different powers require different braking energies during operation, how to match motors of different powers with inverter brake resistors has become a problem that needs to be solved.

First of all, we need to understand the matching principle of inverter brake resistor. Generally speaking, the matching principle of inverter brake resistor mainly includes the following points:

1. The power of the brake resistor should match the rated power of the motor. This is because if the power of the brake resistor is too large, the motor may generate too much heat during the braking process, thus affecting the service life of the motor; conversely, if the power of the brake resistor is too small, it may not be able to meet the energy required by the motor during the braking process, resulting in poor braking effect.

2. The resistance of the brake resistor should match the rated current of the motor. This is because the current will increase rapidly during the braking process of the motor. If the resistance of the brake resistor is too large, it may cause excessive current, thus causing circuit failure; conversely, if the resistance of the brake resistor is too small, it may not meet the current required by the motor during the braking process, resulting in poor braking effect.

3. The type of brake resistor should match the type of motor. Different types of motors may have different types of brake resistors. For example, for AC asynchronous motors, reactors are generally used as brake resistors; while for DC motors, brake choppers are generally used as brake resistors.

Next, let’s take a look at how to match the inverter brake resistor based on the above principles.

First, we need to determine the rated power and rated current of the motor. These two parameters can usually be found on the motor's nameplate. Then, we can choose a suitable brake resistor based on these two parameters. Generally speaking, we can choose a reactor with a resistance between 5-10 times the rated current of the motor as a brake resistor. This can ensure the braking effect and prevent excessive current.

Secondly, we need to consider the type of brake resistor. Different types of motors may have different types of brake resistors. For example, for AC asynchronous motors, reactors are generally used as brake resistors; while for DC motors, brake choppers are generally used as brake resistors. Therefore, we need to choose the appropriate type of brake resistor according to the type of motor.

Finally, we also need to consider the working environment and working conditions of the brake resistor. For example, if the working environment temperature is high, we may need to choose a brake resistor that can withstand high temperatures; if the working environment humidity is high, we may need to choose a brake resistor with good moisture resistance.

In general, the matching of inverter brake resistors is a problem that requires comprehensive consideration of multiple factors. We need to select the appropriate resistance and type of brake resistor according to the rated power and rated current of the motor; at the same time, we also need to consider the working environment and working conditions of the brake resistor. Only in this way can we ensure the performance and service life of the inverter brake resistor, thereby ensuring the safe and stable operation of the motor.