Danfoss VLT Aqua Drive FC 202 Operating Instructions Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

Illustration 9.9: Derating of output current versus altitude at T AMB, MAX. By altitudes above 2 km, pleasecontact Danfoss Drives regarding PELV.An alternative is to lower the ambient temperature at high altitudes and thereby ensure 100%output current at high altitudes.9.2.4. Derating for Running at Low SpeedWhen a motor is connected to a frequency converter, it is necessary to check that the cooling ofthe motor is adequate.A problem may occur at low RPM values in constant torque applications. The motor fan may notbe able to supply the required volume of air for cooling and this limits the torque that can besupported. Therefore, if the motor is to be run continuously at an RPM value lower than half ofthe rated value, the motor must be supplied with additional air-cooling (or a motor designed forthis type of operation may be used).An alternative is to reduce the load level of the motor by choosing a larger motor. However, thedesign of the frequency converter puts a limit to the motor size.9.2.5. Derating for Installing Long Motor Cables or Cables with LargerCross-SectionThe maximum cable length for this frequency converter is 300 m unscreened and 150 m screenedcable.The frequency converter has been designed to work using a motor cable with a rated cross-sec-tion. If a cable with a larger cross-section is used, reduce the output current by 5% for every stepthe cross-section is increased.(Increased cable cross-section leads to increased capacity to earth, and thus an increased earthleakage current).9.2.6. Automatic adaptations to ensure performanceThe frequency converter constantly checks for critical levels of internal temperature, load current,high voltage on the intermediate circuit and low motor speeds. As a response to a critical level,the frequency converter can adjust the switching frequency and/ or change the switching patternin order to ensure the performance of the drive. The capability to automatically reduce the outputcurrent extends the acceptable operating conditions even further.VLT ® AQUA DriveOperating Instructions 9. SpecificationsMG.20.M2.02 - VLT ® is a registered Danfoss trademark 1399