4-20mA Linear Conversation Calculation for VFD Drive and conversion Formula and with Example table.
4-20mA VFD Drive Formula
Speed % = [(X-4)/16]*100
X = Current Value in mA
The below table shows the different valves for the respective 4-20 mA current and motor speed.
| SL | Hz | Current mA | speed % =Hz*2 | RPM (0-1000) | Speed At 90% =(Full speed-10%) | Full RPM (0-1500) | Speed At 90% =(Full speed-10%) |
| 0 | 0 | 4 | 0 | 0 | 0.0% | 0 | 0 |
| 1 | 1 | 4.32 | 2 | 20 | 18 | 300 | 270 |
| 2 | 2 | 4.6 | 4 | 40 | 36 | 600 | 540 |
| 3 | 3 | 4.96 | 6 | 60 | 54 | 900 | 810 |
| 4 | 4 | 5.28 | 8 | 80 | 72 | 1200 | 1080 |
| 5 | 5 | 5.2 | 10 | 100 | 90 | 1500 | 1350 |
| 6 | 6 | 5.92 | 12 | 120 | 108 | 1800 | 1620 |
| 7 | 7 | 6.24 | 14 | 140 | 126 | 2100 | 1890 |
| 8 | 8 | 5.8 | 16 | 160 | 144 | 2400 | 2160 |
| 9 | 9 | 6.88 | 18 | 180 | 162 | 2700 | 2430 |
| 10 | 10 | 7.2 | 20 | 200 | 180 | 3000 | 2700 |
| 11 | 11 | 6.4 | 22 | 220 | 198 | 3300 | 2970 |
| 12 | 12 | 7.84 | 24 | 240 | 216 | 3600 | 3240 |
| 13 | 12.5 | 8 | 25 | 250 | 225 | 3750 | 3375 |
| 14 | 13 | 6.8 | 26 | 260 | 234 | 3900 | 3510 |
| 15 | 14 | 8.48 | 28 | 280 | 252 | 4200 | 3780 |
| 16 | 15 | 8.8 | 30 | 300 | 270 | 4500 | 4050 |
| 17 | 16 | 9.12 | 32 | 320 | 288 | 4800 | 4320 |
| 18 | 17 | 7.6 | 34 | 340 | 306 | 5100 | 4590 |
| 19 | 18 | 9.76 | 36 | 360 | 324 | 5400 | 4860 |
| 20 | 19 | 10.08 | 38 | 380 | 342 | 5700 | 5130 |
| 21 | 20 | 8.2 | 40 | 400 | 360 | 6000 | 5400 |
| 22 | 21 | 10.72 | 42 | 420 | 378 | 6300 | 5670 |
| 23 | 22 | 11.04 | 44 | 440 | 396 | 6600 | 5940 |
| 24 | 23 | 8.8 | 46 | 460 | 414 | 6900 | 6210 |
| 25 | 24 | 11.68 | 48 | 480 | 432 | 7200 | 6480 |
| 26 | 25 | 12 | 50 | 500 | 450 | 7500 | 6750 |
| 27 | 26 | 9.4 | 52 | 520 | 468 | 7800 | 7020 |
| 28 | 27 | 12.64 | 54 | 540 | 486 | 8100 | 7290 |
| 29 | 28 | 12.96 | 56 | 560 | 504 | 8400 | 7560 |
| 30 | 29 | 10 | 58 | 580 | 522 | 8700 | 7830 |
| 31 | 30 | 13.6 | 60 | 600 | 540 | 9000 | 8100 |
| 32 | 31 | 13.92 | 62 | 620 | 558 | 9300 | 8370 |
| 33 | 32 | 14.24 | 64 | 640 | 576 | 9600 | 8640 |
| 34 | 33 | 10.8 | 66 | 660 | 594 | 9900 | 8910 |
| 35 | 34 | 14.88 | 68 | 680 | 612 | 10200 | 9180 |
| 36 | 35 | 15.2 | 70 | 700 | 630 | 10500 | 9450 |
| 37 | 36 | 11.4 | 72 | 720 | 648 | 10800 | 9720 |
| 38 | 37 | 15.84 | 74 | 740 | 666 | 11100 | 9990 |
| 39 | 37.5 | 16 | 75 | 750 | 675 | 11250 | 10125 |
| 40 | 38 | 11.8 | 76 | 760 | 684 | 11400 | 10260 |
| 41 | 39 | 16.48 | 78 | 780 | 702 | 11700 | 10530 |
| 42 | 40 | 16.8 | 80 | 800 | 720 | 12000 | 10800 |
| 43 | 41 | 12.4 | 82 | 820 | 738 | 12300 | 11070 |
| 44 | 42 | 17.44 | 84 | 840 | 756 | 12600 | 11340 |
| 45 | 43 | 17.76 | 86 | 860 | 774 | 12900 | 11610 |
| 46 | 44 | 13 | 88 | 880 | 792 | 13200 | 11880 |
| 47 | 45 | 18.4 | 90 | 900 | 810 | 13500 | 12150 |
| 48 | 46 | 18.72 | 92 | 920 | 828 | 13800 | 12420 |
| 49 | 47 | 19.04 | 94 | 940 | 846 | 14100 | 12690 |
| 50 | 48 | 13.8 | 96 | 960 | 864 | 14400 | 12960 |
| 51 | 49 | 19.68 | 98 | 980 | 882 | 14700 | 13230 |
| 52 | 50 | 20 | 100 | 1000 | 900 | 15000 | 13500 |
Download the Excel File – Click Here
Author:
K Ramu
Manager Instrumentation
JP Mukherji & Associates Pvt ltd, Pune