Danfoss VLT HVAC Drive FC 100 Series Design Manual

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Danfoss VLT HVAC Drive FC 100 Series Design Manual Manual pdf 182 page image

3. RFI filter choke.Typical values are measured at a distance of 3.28 ft. [1 m]from the unit:EnclosureAt reduced fanspeed (50%) [dBA]***Full fan speed[dBA]A2 51 60A3 51 60A5 54 63B1 61 67B2 58 70B3 59.4 70.5B4 53 62.8C1 52 62C2 55 65C3 56.4 67.3C4 - -D1/D3 74 76D2/D4 73 74E1/E2* 73 74** 82 83F1/F2/F3/F4 78 80* 425 hp [315kW], 380–480V AC and 600–675 [450–500kW], 525–690V AC only.** Remaining E1/E2 power sizes.*** For D, E and F sizes, reduced fan speed is at 87%, measuredat 200V.Table 8.168.5 Peak voltage on motorWhen a transistor in the inverter bridge switches, thevoltage across the motor increases by a du/dt ratiodepending on:- the motor cable (type, cross-section, length,shielded or non-shielded)- inductanceThe natural induction causes an overshoot UPEAK in themotor voltage before it stabilizes itself at a leveldepending on the voltage in the intermediate circuit. Therise time and the peak voltage UPEAK affect the service lifeof the motor. If the peak voltage is too high, motorswithout phase coil insulation are especially affected. If themotor cable is short (by a few yards), the rise time andpeak voltage are lower.If the motor cable is long (328 ft [100 m]), the rise timeand peak voltage increases.In motors without phase insulation paper or otherinsulation reinforcement suitable for operation withvoltage supply (such as a Adjustable frequency drive), fit asine-wave filter on the output of the Adjustable frequencydrive.To obtain approximate values for cable lengths andvoltages not mentioned below, use the following rules ofthumb:1. Rise time increases/decreases proportionally withcable length.2. UPEAK = DC link voltage x 1.9(DC link voltage = AC line voltage x 1.35).3.dU /dt =0.8 ×UPEAKRisetimeData are measured according to IEC 60034-17.Cable lengths are in meters.Adjustable Frequency Drive, P5K5, T2Cablelength (ft [m])AC linevoltage [V]Rise time[μsec]Vpeak[kV]dU/dt[kV/μsec]118.1 [36] 240 0.226 0.616 2.142164 [50] 240 0.262 0.626 1.908328 [100] 240 0.650 0.614 0.757492.1 [150] 240 0.745 0.612 0.655Table 8.17General Specifications and ... VLT® HVAC Drive Design Guide8-22 MG11BB22 - VLT® is a registered Danfoss trademark88