5.2 Derating for Long Motor Cables orCables with Larger Cross-SectionNOTICEApplicable for frequency converters up to 90 kW only.The maximum cable length for this frequency converteris 300 m unscreened and 150 m screened cable.The frequency converter has been designed to workusing a motor cable with a rated cross-section. If a cablewith a larger cross-section is used, reduce the outputcurrent by 5% for every step the cross-section isincreased.Increased cable cross-section leads to increased capacityto earth, and thus an increased earth leakage current.5.3 Derating for Ambient TemperatureThe average temperature (TAMB, AVG) measured over 24hours must be at least 5 °C lower than the maximumpermitted ambient temperature (TAMB,MAX). If the frequencyconverter operates at high ambient temperatures, thendecrease the continuous output current. Derating dependson the switching pattern, which can be set to 60° AVM orSFAVM in 14-00 Switching Pattern.5.3.1 Derating for Ambient Temperature,Enclosure Size A60° AVM – Pulse Width Modulation220%4 6 8 10 12 14 1640%60%80%100%110%Iout (%)fsw (kHz)A1-A3 45°C, A4-A5 40°CA1-A3 50°C, A4-A5 45°CA1-A3 55°C, A4-A5 50°C 130BA393.1000Illustration 5.3 Derating of Iout for Different TAMB, MAX forEnclosure Size A, using 60° AVMSFAVM – Stator Frequency Asyncron Vector Modulation220%4 6 8 10 12 14 1640%60%80%100%110%A1-A3 45°C, A4-A5 40°CA1-A3 50°C, A4-A5 45°CA1-A3 55°C, A4-A5 50°C00130BD639.10Iout (%)fsw (kHz)Illustration 5.4 Derating of Iout for Different TAMB, MAX forEnclosures Type A, using SFAVMWhen using only 10 m motor cable or less in enclosuresize A, less derating is necessary. This is due to the factthat the length of the motor cable has a relatively highimpact on the recommended derating.60° AVM220%4 6 8 10 12 14 1640%60%80%100%110% I out (%)A1-A3 45°C, A4-A5 40°CA1-A3 50°C, A4-A5 45°CA1-A3 55°C, A4-A5 50°C00130BA394.10fsw (kHz)Illustration 5.5 Derating of Iout for Different TAMB, MAX forEnclosures Type A, using 60° AVM and Maximum 10 m MotorCableSFAVM220%4 6 8 10 12 14 1640%60%80%100%110%I out (%)A1-A3 45°C, A4-A5 40°CA1-A3 50°C, A4-A5 45°CA1-A3 55°C, A4-A5 50°C00130BD640.10fsw (kHz)Illustration 5.6 Derating of Iout for Different TAMB, MAX forEnclosures Type A, using SFAVM and Maximum 10 m MotorCable5.3.2 Derating for Ambient Temperature,Enclosure Size BEnclosure B, T2, and T460° AVM – Pulse Width Modulation220%4 6 8 10 12 14 1640%60%80%100%110%fsw (kHz)00Iout (%)NO45°C50°C55°C130BA401.11B1B2Illustration 5.7 Derating of Iout for different TAMB, MAX forEnclosure Sizes B1 and B2, using 60° AVM in Normal OverloadMode (110% Overtorque)Special Conditions Design GuideMG20N602 Danfoss A/S © 09/2014 All rights reserved. 1115 5
