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January 23, 2012Comparison of Air-Cooled and Liquid-Cooled Eddy Current Brakes
| Eddy-Current brakes provide fast, reliable load control for a variety of industrial applications. Eddy-Current brakes also offer moderate inertia and have a particularly high load capacity. These work well for the lower RPM range that’s typical of most industrial motors. Two main types of Eddy-Current brakes are air-cooled and liquid-cooled brakes. Let’s compare how these work as well as their similarities.
Air-Cooled Eddy-Current Brakes Air-cooled type brakes feature a rotating member or rotor and are keyed to a straight-through double extension shaft and a stationary brake coil. These are usually the most cost effective brakes in applications that do not require stall-speed loading. Air-cooled brakes usually cost less than liquid-cooled because there’s no need for an external water supply or resistor banks. Air-cooled Eddy-Current brakes also usually allow for more flexibility than hydraulic pumps. |
Liquid-Cooled Eddy Current Brakes
Liquid-cooled brakes are used in more demanding applications, such as those requiring a higher RPM limit, temperature independence (continuous duty), and lower system inertia. These offer quick load control and work well with industrial motors that do not require motoring or stall speed loading. Same as air-cooled brakes, liquid-cooled brakes feature a rotor and are keyed to a straight-through double extension shaft and a stationary brake coil. But unlike air-cooled brakes, these are also keyed to an automatic water piping system for flow-through liquid cooling.
Similarities
Both types of Eddy-Current brakes provide controlled deceleration of the motor at variable speeds. They offer smooth response because the rotating and stationary parts have no physical contact. Having no contact also eliminates shock loading and extends the equipment life.
Both types of brakes may have an optional tachometer generator that provides feedback to the controller (using feedback signal). This tachometer generator is mounted externally for the air-cooled brakes and internally for the liquid-cooled brakes. Its signal is compared against a reference signal inside the controller, resulting in smooth, accurate and controlled braking. Constant speed and torque may be achieved as well.
Common industrial applications for Eddy-Current brakes include load braking, centrifuges, overhead cranes and dynamometer testing.
Carotron now offers Air-Cooled and Liquid Cooled Eddy-Current brakes from DSI Dynamatic, rating from .25 to 4000 horsepower. There’s also a wide selection of Dynamatic drives to meet control demands of today in many industrial settings.
Call Carotron to discuss your needs today: 1-888-286-8614
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