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AB2005

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  1. Hi; I want to control the speed of 3 single phase motors each 120W by a 3phase inverter drive. In this case, the motors will be connected in star connection. How about this idea? Please share your experience.
  2. On start, initial voltage starts from 235V and current goes up to 255A and returns back to 42A within 10Sec. When motor reaches at almost 80% speed, bypass contactor is on. If we increase the initial voltage 250V, the current goes up to 292A.
  3. Thanks Mark. Its mean, with present conditions, we will have to install VFD to increase number of starts per hour as we can not reduce slip losses.
  4. Hi; Hopping that every one is fine with good health. Many years passed to Log-in. Now need help on an application where we have installed soft starter. We have a trim waste blower at Corrugator machine which has a 380V, 30KW, 4pole AC motor which drives an impeller by the mean of V-belts with double of motor speed. Previously motor was running by star delta starter. As we can not go beyond 6-7 start/stop per hour for such kind of load, so during normal operation of corrugator, if machine was stopped for some reason, trim waste blower was not stopped. As we calculated that if we stop the blower on each machine stop and start on machine start, we can save energy. So we have installed soft starter 37KW Schneider ATS01N272Q. But we have observed that when blower is start, current goes up to 272A and remains the same for almost 3-4sec, after that current starts dropping and stays at 42A (motor coils connected in delta). The total time which blower takes from zero to max speed is around 6-8sec. We have set the initial voltage around 260v. We always used VFD to control the speed and never used soft starter, so dont have idea about correct operation of soft starter. So, please guide me on following points; Is above mentioned condition normal? How many times can we start/stop the motor in an hour by soft starter?
  5. Dear Friends; We have 220V, 1HP, 8A, 1430rpm motors for blowers. To protect the motors against overloading, we want to add safety. As normal circuit breaker do have thermal characteristics, so can we use 9/10A circuit breaker instead of overload type circuit breaker 6.5A-9.5A which usually available in 3poles? If a normal circuit breaker costs $3 then a 3pole overload type circuit breaker costs $30. So kindly guide me if we can use the circuit breaker or not if not than what is the reason.
  6. Dear Friends; We have 220V, 1HP, 8A, 1430rpm motors for blowers. To protect the motors against overloading, we want to add safety. As normal circuit breaker do have thermal characteristics, so can we use 9/10A circuit breaker instead of overload type circuit breaker 6.5A-9.5A which usually available in 3poles? If a normal circuit breaker costs $3 then a 3pole overload type circuit breaker costs $30. So kindly guide me if we can use the circuit breaker or not if not than what is the reason.
  7. Hi Mark; First of all, I am grieved that your cricket team which was my favorite in the final of World Cup 2015 and I wished that New Zealand should win the world cup but they could not perform well. Anyhow this is the game of that specific day. We have a manual hydraulic baling press machine to make the bundles of trim cutting waste of Corrugator and Flexo machines. As there is no any torque control or limit control, some times operator presses the collected waste in the bin with excessive force which is harmful for baler parts. We can not install a limit switch because the quantity of waste in the bin is not the same every time. I have an idea to control the torque of motor so that after a set point of torque, motor should stop to press more the waste. Please do share if you have a cheaper solution for this kind of control. Motor is 37KW 400V which runs a hydraulic pump.
  8. Hello Marke; I could not attach an MS Excel file of 459kb in size with this post.
  9. Hi; In these days, our management is working to buy another new flexo printing machine from a Swedish company. The existing machine has a main DC motor 49KW which drives a long shaft. Rotating parts of each unit (feeder, printing, slotting, die-cutting folding counter ejector) are attached with this shaft via gear boxes. In selection of new machines, we have two options; First machine, each unit (feeder, printing, slotting, die-cutting folding counter ejector) has a main servo motor and then timing belts to rotate rotating part of individual unit. For example, in feeder unit, there are five rolls which are attached with gear box. And thus 06nos synchronized servo motors (excluding other almost 48 small AC setting motors) instead of one main motor. In second machine, all the rotating parts of machine have their own individual servo motor. And thus total 48 synchronized servo motors (excluding other almost 48 small AC setting motors) and no any gear box. For me, the machine having 06servo motor is better than that machine having 48servo motors because when we increase the no-of motors, problems are also increased. What do you think? Please dont consider the cost, just a technical question.
  10. Dear Friends; We have a screw air compressor Atlas Copco GA808 which has a 75KW 500V motor runs on star delta. As we have 400V power supply system, so initially we want to run this compressor on 400V to test it with load. So what will happen with its motor when we run it on 400V? Obliviously its torque will be reduced but for how much percentage?
  11. Hi; After having an upgrade of our corrugator machine's rotary cut-off unit, we have old ABB servo motors for sale which name plate images are attached. Please let me inform if anyone knows about such party who can purchase these motors from us. Quantity 04nos. http://i1155.photobucket.com/albums/p553/signode/ABBServoMotorforCut-off_Nameplate_1_zpsb5f9b0bf.jpg http://i1155.photobucket.com/albums/p553/signode/ABBServoMotorforCut-off_Nameplate_2_zps6dda0c8e.jpg http://i1155.photobucket.com/albums/p553/signode/ABBServoMotorforCut-off_zpsb177aa07.jpg
  12. Hi; Please see the attached image which is a diagram of power circuit of a 95KW DC drive. There are two fuses mentioned for each phase and each fuse is 660V 200A rated. Am I correct that one fuse of each phase is for forward operation and second fuse is for reverse operation? Please make me correct if mistaking. This drive (almost 20years old) runs a 93.6KW motor of a single facer unit of Corrugator machine. We have been facing a problem with this drive that some time (after one or two months) its fuses blow out. Some time three fuses some time four and some time five. There is no any jamming in machine which leads to blow out the fuse. We have made test of motor and found it ok. Matter of thinking is that why fourth or fifth fuses are blown.
  13. Hello; In a flexo printing machine, we are going to upgrade its folding belts system for which, after final calculations, we are required a 3phase 5KW 950rpm motor to provide 600rpm at driven side. A question raises here that what happen if we select a 5KW 1450rpm motor (instead of 5KW 950rpm) and reduce the speed at driven side by reducing the teeth of chain sprockets. Would there be same torque in both cases? This is why that normally 6poles motors are rarely available in our local market while 4poles are easily available. There is no any issue of space for sprockets and motors.
  14. Hi; Normally the rating of all kind of other motors whether AC or DC quote in kilowatts but with Servo motor, its rating doesn’t quote, just torque expressed in Newton meter (name plate of a servo motor is attached for reference). What is the technical reason behind it? For example, how do I convert 41.5 Newton meter torque of a servo motor into kilowatts?
  15. I installed a 1275kva rental genset during a power shutdown period and found no any issue with its operation with running all machines but max load was recorded on it was one problem i observed that while generator was in operation, the Nokian PF relay was switched on the required capacitors and after few minutes, it switched off the all capacitors and then again switched on step by step. That cycle was repeating again and again. Some time same happens with utility power but after cycle the power of Nokian PF relay, it become normal but with generator in-operation case, it did not go to normal after cycled its power.
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