文档介绍：Sizing Dynamic Brake Resistors and Chopper Modules
Dynamic Brake Module Circuit
Using a Dynamic Brake or Chopper
In general, the motor power rating, speed, torque, and details of the regenerative duty cycle need to be known.
Generally, a dynamic brake can be used whenever regenerative energy is dissipated on an occasional or periodic basis.
If the drive will consistently be regenerating, serious consideration should be given to returning the power to the AC utility.
Gather the Information First
The nameplate power rating of the motor in watts, kilowatts, or horsepower.
The nameplate speed rating of the motor in rpm, or rps.
The motor inertia and load inertia in kilogram-meters2, or lb-ft2.
The gear ratio, if a gear is present between the motor and load, GR.
The motor shaft speed, torque, and power profile of the drive application.
Example Speed, Torque, and Power Profile
t
t
t
How to Choose a Dynamic Brake / Chopper
Calculate the total inertia of the system
Calculate the peak regenerative power you need to dissipate.
This will determine the maximum allowable resistance value of the DB resistor.
Calculate the average power dissipation
This will determine the average power dissipation capacity needed in the DB resistor.
Third, check to see that the peak temperature of the dynamic braking resistor does not exceed its capacity.
Plot the Average Load and Peak Load on the curve in the sizing guide. This is necessary only on the dynamic brake modules!
Dynamic brake modules should only be used on drives 75HP and smaller.
How to Size A Dynamic Brake Module
Step 1 - Total Inertia
JT = total inertia reflected to the motor shaft, kilogram-meters2 (kg-m2) or pound-feet2 (lb-ft2)
Jm = motor inertia, kilogram-meters2 (kg-m2) or pound-feet2 (lb-ft2)
GR = the gear ratio for any gear between the motor and load, dimensionless. 2:1 =
JL = load inertia, kilogram-meters2 (kg-m2) or pound-feet2 (lb-ft2)
Note: -ft2 = kg-m2
DB Module
Step 2 - Peak Regen