Contents
How do you size a dynamic brake resistor?
To calculate the right size of the resistor you need the characteristic data of the load cycle: brake time or duty cycle and the total cycle time. Furthermore you need the brake power Pbr and the minimum resistance value Rmin which is defined by the VFD.
What is dynamic braking method?
Dynamic braking is the use of an electric traction motor as a generator when slowing a vehicle such as an electric or diesel-electric locomotive. It is termed “rheostatic” if the generated electrical power is dissipated as heat in brake grid resistors, and “regenerative” if the power is returned to the supply line.
What is the function of braking resistor?
The purpose of a brake resistor is to help perform motor braking or overhauling by absorbing regenerated braking energy and dissipating it as heat with rheostatic resistors. This page is primarily focused on the application of dynamic braking resistors with low voltage drives.
How to calculate the size of a braking resistor?
To calculate the right size of the resistor you need the characteristic data of the load cycle: brake time or duty cycle and the total cycle time. Furthermore you need the brake power Pbr and the minimum resistance value Rmin which is defined by the VFD.
What is the torque of a dynamic braking resistor?
Motor Data: 5 HP, 460 vac, 6.8 amps, 1760 rpm, 0.857 pf, 0.90 eff, rotor inertia = 0.74 lb-ft2 (TEFC frame vector duty) Braking Requirements: 150 % of motor rated torque 2. CTAN291 V1.1 Page 2 of 10 12/8/2010 The drive we will use is the SP1405 which is rated at 7.6 amps continuous (Heavy Duty).
Which is the best brand of braking resistors?
KWK Resistors has the expertise to compute, design customized and application-specific resistors that are particularly good at handling high pulsed powers. Dynamic Braking Resistors from KWK come with varied resistance, power, and current ratings.
How does a braking resistor work in a VFD?
In a variable frequency drive (VFD) application the motor will feed back braking energy into the DC link when it is in braking operation. This may cause a DC link voltage rise up to a critical level. A braking resistor will compensate this energy and convert it to thermal energy.