變頻器制動電阻選擇和計算方法-資料下載頁
2025-05-14 21:42本頁面
【正文】 ogrammeters2 (kgm2) or poundfeet2 (lbft2) Note: = kgm2 Copyright 169。 2021 Rockwell Automation, Inc. All rights reserved. Step 2 Peak Regenerative Power ? ?23 ttxJP obbTb??????JT = total inertia reflected to the motor shaft, kgm2 ?b = max angular rotational speed, Rad/s = 2pNb/60 ?o = angular rotational speed, less than rated speed (can be zero) Rad/s Nb = maximum application speed in RPM t3t2 = total time of deceleration from ?b to ?o, seconds Pb = peak braking power, watts Note: HP = 746 watts Copyright 169。 2021 Rockwell Automation, Inc. All rights reserved. Step 3 Maximum DB Resistor Value bddbPVR21 ?Vd = the value of DC Bus voltage that utilizes the full capability of the drive. 395VDC or 790VDC or 987VDC Pb = peak braking power calculated in step 2 Rdb1 = the maximum allowable value for the dynamic brake resistor Resistor tolerances are built into the minimum resistances for each individual drive Copyright 169。 2021 Rockwell Automation, Inc. All rights reserved. About Duty Cycle ? ? ? ?234234 9 0 0 t h e n 9 0 0 If tttttt ??????Given that a resistor cools off in about 15 minutes, if cycle time minus the decel time exceeds 900 then using the larger cycle time can’t be used for calculating average power. ? ( t )( t )( t )TP P bt t 4 tt 4t1 +t321t0t t 4 tt 4t1 +t321t0t t 4 tt 4t1 +t321t0Let’s say that I decel in 10 seconds every hour. That would be 10 / 3600 or times the peak power. What if I decel in 50 seconds once a day? Or 60 seconds once a week? Copyright 169。 2021 Rockwell Automation, Inc. All rights reserved. Step 7 Estimate Resistor Wattage ?????? ???bobbavPxtttP???2)(423Pav = average dynamic brake resistor dissipation, watts t3t2 = elapsed time to decelerate from ?b speed to ?o speed, seconds t4 = (adjusted) total cycle time, seconds Pb = Peak braking power, watts ?b = maximum motor speed, Rad/s ?o = a slower motor speed, Rad/s Copyright 169。 2021 Rockwell Automation, Inc. All rights reserved. Step 8 – Calculate WattSeconds ? ?223bwsPxttP ??Pws = required wattseconds of the resistor t3t2 = elapsed time to decelerate from ?b speed to ?o speed, seconds Pb = Peak braking power, watts Copyright 169。 2021 Rockwell Automation, Inc. All rights reserved. More discussions: Intermittent overhauling loads. Doubling up chopper units.
環(huán)評公示相關(guān)推薦
鄂ICP備17016276號-1