The performance output that you see on listings for motors is specified for when they are operating in an area near or at sea level. It does not count higher altitudes in its rating, because similar to how humans struggle to breathe at higher altitudes, motors also perform worse at great heights.
The environment changes significantly as we go up, which can be detrimental to the performance of motors as they depend on favorable conditions for optimal results. After a certain point of elevation, it's recommended to derate the motor in order to ensure longevity. Here are a few of the reasons behind this drop in quality:
Differences in Air Quality
As the altitude increases, there’s also a significant change in air quality. The level of humidity goes down along with air pressure and density, but the temperatures increase inversely. Hoist motors, which depend on ambient air for cooling purposes begin to struggle here. They require intake of cool air and discharge of the warm to dissipate heat. At higher altitudes, rather than receive cool air, they get warm air which does not ease their job in regulating the temperatures.
Apart from the increasing ambient temperature, the air is also much thinner as you progressively go above sea level. As the air grows thinner, the motors that depend on air for cooling start to struggle, to the point of requiring derating in performance in order to keep it running. Heat dissipation becomes significantly more difficult and without derating the motor, you can end up damaging it by pushing it to its limits.
For every 1640 feet of altitude that you gain as you progress above 3,280 feet above sea level, you must derate 3% off of the total capacity that your motor performs at. With increasing height, this level of deration must continue to prevent the motor from damaging itself.
A provider of Rayco-Wylie products since 2001, Crane Warning Systems Atlanta is here to serve the needs of your industry. Rayco-Wylie is the go-to name when it comes to safety in the construction industry. We don’t just sell products; buy we provide aftersales services to ensure that our customers remain our recurring customers. We also have service, support and parts for Rayco-Wylie products, with a wide inventory of items like crane anemometer, crane ATB systems, load indicators, anti-two block warning systems and crane wind speed indicator.