The stainless steel Starting and Braking resistors are used for a wide range of applications like cranes, pumps, big fans, compressors and generally anywhere is necessary to control a large electric motor during the starting and stopping phases.
Installations in harsh environments like steelworks, harbors or oil platforms are feasible and can be implemented on request without any specific limitation.
The most common resistors typologies of this products family are:
Rotor starting/braking resistor
This resistor allows a stepped starting having high starting torque with low and limited starting currents. Suggested for high power motors and to drive equipments with strong inertia and needs of fast accelerations and heavy, long and frequent startings
Stator starting/braking resistor
This resistor is used for gradual starting with the possibility to choose the torque in relation with the device to start. Suggested for equipments with low starting torque and increasing advancement.
Dynamic Braking resistor (DBR)
The dynamic braking is particularly suited for motors driven by inverter. The motor is brought to brake by reducing the power supply, realizing a negative running. The asynchronous device will work as a generator, therefore will supply electrical power. This electrical power is dissipated by an external braking resistor, linked right upstream the inverter, avoiding this way the activation of protections which will result in a block of the very same inverter. The inverter can dissipate the regenerated energy during the AC motor braking up to the 3% of its rated power.
Water cooled dynamic braking
These modular resistors are cooled directly in water (fresh or water-glycol) or indirectly via water-cooled heat sinks. They can be an efficient option that reduce the construction size being possible to stack several resistor modules close. The single resistor module, based on a glass-filled plastic enclosure with a resistor element inside, can support up to 25 kW continuous power with a limited overloads.
The oil-cooled starters are stepped resistor starters with contactors and resistor grids in a housing filled with insulating oil and are particularly suited for high performance drives that are not frequently started. The design combines the advantages of a resistor starter with those of a more economical heat carrier (oil) and a high protection class IP54 for applications in difficult environments.