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Topics: How to select brake unit/brake resistor for inverters on Accessories
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08-13-2012 11:03 AM

How to select brake unit/brake resistor for inverters

I have a 3HP and 10HP inverters, i need the brake unit & brake resistor for fast deceleration, what's the capacity unit/resistor for it?
08-13-2012 11:08 AM
Top #2
08-13-2012 11:08 AM
Brake unit, also called the transducer dynamic braking unit, or inverter dedicated energy feedback unit is mainly used to control the mechanical load is relatively heavy, braking speed is very fast occasions, theof renewable electricity generated by the motor consumed by the braking resistor or regenerative current feedback loop current.

In some applications require rapid deceleration, according to the asynchronous motor principle known, if the slip The greater the difference the greater the torque Similarly braking torque will increase with the spin-down rate increases, the system drop greatly reducing the speed of time, energy feedback is greatly accelerated, rapid increase in the DC bus voltage, and must therefore be that the feedback energy is rapidly consumed, and keep the DC bus voltage below a safe range. Main function is to quickly brake unit system, the energy consumed (energy converted into heat by the braking resistor distribution). It is effective to make up for the ordinary inverter braking speed is slow, braking torque is small (= 20% of rated torque) the shortcomings of occasions to be rapid braking but the frequency of lower.
08-13-2012 11:12 AM
Top #3
08-13-2012 11:12 AM
When the inverter driven motors need to stop, the motor carried by the load is the kinetic energy to stop the motor, it is necessary to kinetic energy is consumed in order to stop the motor.
Consumption of these kinetic energy, you can use the device of the brake as the car's brakes, its principle is the kinetic energy into heat energy to consume the kinetic energy of the motor shaft.
Another option is that you said the brake unit with a braking resistor. The principle is the kinetic energy into heat, the resistance heating in the form of the motor on the kinetic energy consumed.
As for how to choose the brake unit and resistor, there are several factors to consider:
(1) the kinetic energy of the motor shaft. Different loads, the kinetic energy of the motor shaft is different, for example, applied to the crane motor, in addition to the kinetic energy, there are objects in potential energy, should add up to count to the motor shaft, the energy must be consumed in the resistor.
(2) to calculate how much energy needs to consume, it can be converted into an electric current, to select the brake unit. Before the election braking resistor (resistance temperature characteristics to be considered to select), then select the accompanying braking unit (see manufacturers manual).
3 Note that the motor is calculated kinetic energy, as to how much resistance you want to select another factor is the braking time. If the brake is a very short period of time, it needs a relatively large resistance, and vice versa, you can choose a small resistance. This depends on the mechanical requirements.
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