The brushless dc motor in the south of anhui after-sales service case 4: YZQ BLDC motor start-up failure

After-sales service case 4: brushless dc motor in the south of anhui anqing two YZQ - a centrifuge factory feedback 315年代 4 V6 415 v / 50 hz brushless dc motor in the same equipment in the same control system, one works, one cannot start, customers don't think you can do starting a brushless dc motor must have a fault, brushless dc motor after returned to the factory to do the full performance test, the result all normal, return the user to test again, after failure remains. On-site inspection processes and results: first, check the equipment and quality of power supply, all equipment is normal, the power supply of 395 v / 50 hz, 415 v voltage is not in conformity with the brushless dc motor. Secondly, to confirm the equipment is normal, the equipment is installed on a YZQ - 315年代 4 V6 380 v / 50 hz brushless dc motor testing, star - Triangle conversion starting, conversion time of 300 s, starting current 280 a, 60 s 252 a, 120 s 230 a, 180 s 205 a, 240 s began to rapid decline in 30 years, the 300 s when run into a triangle, the current 81 a, normal operation. Third, confirm equipment normal after the original 380 v / 50 hz brushless dc motor replacement for 415 v / 50 hz, no-load starting not to install belt, star after starting current 287 a, moment down to current 5 s of 26 a, 300 s transformation triangle run, starting everything is normal. Fourth, after the no-load test normal install belt, belt centrifuge starting, starting current 287 a, star 60 s 251 a, 120 s 233 a, 180 s 216 a, 240 s 204 a, 300 s when run into a triangle, current rapid increase to 580 a, over-current protection movement, the starting failure. Fifth, analysis of 380 v / 50 hz starting data, starting from the 240 s when the rapid decline in current, in the 415 v / 50 hz BLDC motor starting failure before there has been no significant current decline, estimation is the starting time is not enough, after the user agrees to fuses iconic - Triangle conversion time increased to 350 s, before the 300 s, as the first test, starting from the 310 s current rapid decline, 340 s current for 21 a, 350 s transform triangular operation, current is 71 a, start to finish, all is well. Case analysis: field test voltage is 395 v / 50 hz, and brushless dc motor is used export, rating of 415 v / 50 hz, because of the brushless dc motor torque is proportional to the voltage, the voltage drop caused by starting torque smaller, resulting in the star of brushless dc motor running 300 s was not fully start, speed not close to the rated speed, at the moment is converted into a triangle secondary starting operation of brushless dc motor, a large starting current, so the over-current protection action, starting after the extension of the conversion time is normal, the actual time only 15 s. Why two 415 v / 50 hz a normal a brushless dc motor doesn't work, because two brushless dc motor's starting torque is small, and just starting time also need only 15 s. This article by the brushless dc motor in the south of anhui anhui co. , LTD. Original, reproduced please indicate the source.