What are the braking resistors conditions?
Dynamic braking resistors are used on AC variable frequency drives (VFD’s) to dissipate energy that is produced in the motor as the drive provides braking torque to stop the motor. The dynamic braking resistor is connected to the DC bus and will see voltages as high as 800 volts during braking conditions.
What is a draw works in drilling?
1. n. [Drilling] The machine on the rig consisting of a large-diameter steel spool, brakes, a power source, and assorted auxiliary devices. The primary function of the drawworks is to reel out and reel in the drilling line, a large diameter wire rope, in a controlled fashion.
What is duty cycle in dynamic braking resistor?
Choosing the Brake Resistor The duty cycle rating is based on a 60 second period. For example, the 20 percent duty cycle resistor can carry 100 percent cur- rent for 12 seconds out of every 60 seconds, while the 50 percent duty cycle resistor can carry 150 per- cent current for 30 seconds out of every 60 seconds.
What is brake resistor in VFD?
Braking resistors are used for applications where the motor speed exceeds the speed that is set by the variable frequency drive (VFD) or when fast deceleration is required. They can provide controlled braking at an increased torque. The surplus energy will be fed into the VFD and increase the voltage on the DC bus.
What is tool pusher in drilling?
The toolpusher is usually a senior, experienced individual who has worked his way up through the ranks of the drilling crew positions. His job is largely administrative, including ensuring that the rig has sufficient materials, spare parts and skilled personnel to continue efficient operations.
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 type of brakes do you have in your drawworks?
Drawworks brakes Our drawworks are equipped with several types of braking systems to provide maximum performance and safety. All drawworks are equipped with at least one of the following: • Universal disc brakes • Band brakes • NOV friction-plate brakes • Hydraulic caliper disc brakes • Air caliper disc brakes • Baylor® eddy current brakes
What size brake resistor do I need for my Drive?
Again, the size of the braking resistor can be greatly affected by frequency of stopping. For applications requiring an occasional stop, a resistor rated at 5-10% of the drive rating is adequate where as an indexing application, may require as much as a 50% to 75% of the drive rating.
Why choose dynamic braking resistors from KwK?
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.
What does the resistance value of a brake resistor mean?
The resistance value sets the rate at which we put the energy into the resistor – the braking power. The lower the resistance value, the higher the power. The minimum ohms are set by the drive manufacturer, and will produce braking power at the peak rating of the drive (or its braking module).
