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  1. M

    Help!!! 2395 practical tomorrow!!!!

    Forgot to say thanks for all you comments. For everybody's information, the 2395 written exam has changed format considerably from the 2391. The exam is now made up of 6 questions, each made up of 15 points. Three of these questions are based on an accompanied scenario. The whole exam now...
  2. M

    Help!!! 2395 practical tomorrow!!!!

    Hi all, Well thank god that's over! Put me in an exam situation and I just fall to bits! I'm sure my sweaty palms could have been classed as an external influence! All went well though, thanks. Just have to wait for my results from the written component now. Only a few weeks.
  3. M

    Help!!! 2395 practical tomorrow!!!!

    Thanks youngbart, the time hath cummeth! On to the slaughter.
  4. M

    Insulation Resistance query

    Could it not be down to harmonics? All that electronic stuff plays havoc and lots of distortion on the mains supply. This coupled with an RCD could definitely cause some nuisance tripping. Is that not why they have functional earths for installations with lots of electronics and Residual Current...
  5. M

    Help!!! 2395 practical tomorrow!!!!

    Hi everyone, Can anyone give me any advice on the order of tests for my practical exam tomorrow. Do I test first and then fill in my schedule of inspections? I feel as though time will be an issue! Please, any advice would be grateful
  6. M

    Damage caused to VSD from insulation tester voltage

    The machine is a centrifuge. A large barrel shaped hollow bowl that spins at speeds up to 1200 rpm with a screw conveyor inside that turns at a differential speed to the bowl. All run from variable speed drives. The drive that is faulty is the bowl drive. This normally stays at a single speed...
  7. M

    Damage caused to VSD from insulation tester voltage

    From what I've been told, the problems arose because they did not disconnect the drive prior to testing. I would have expected the IGBT modules to take the brunt of whatever damage the test had done, and this would have materialised in a short circuit fault, not overcurrent.
  8. M

    Damage caused to VSD from insulation tester voltage

    I'm lucky in that I think the process will allow the use of the drive in SCALAR. I'm just concerned that there may be an underlying issue that could cause further problems down the line.
  9. M

    Damage caused to VSD from insulation tester voltage

    There is no encoder fitted. There is no feedback to the drive. The DTC mode calculates, then compares this calculation to the reference value. I think this is how it goes!
  10. M

    Damage caused to VSD from insulation tester voltage

    The load is belt driven, and with the belts removed it runs only in scalar. All parameters are the same, whether run in DTC or SCALAR. Motor data and limits unchanged. ABB drives just use three PCB mounted CT's so if one/any had a fault it would show in both running modes. This is very...
  11. M

    Damage caused to VSD from insulation tester voltage

    So the main supply is under estop control aswell as the output? This is just to totally isolate the drive under estop conditions?
  12. M

    Damage caused to VSD from insulation tester voltage

    Hi mheyes, I would normally have a contactor on the incoming side of the drive, this then acts as with the emergency stop circuit. Would it not cause any problems switching the output? What is the contactor normally used for? Estop control?
  13. M

    Damage caused to VSD from insulation tester voltage

    Hi guys, The test was performed on the output from the drive. It now powers up, but will only run in scalar mode rather than the normal direct torque control mode. If run in DTC it faults on overcurrent. The drive is a 3P 400 v input driving a 3P 400 v nominal output. Really simple...
  14. M

    Damage caused to VSD from insulation tester voltage

    Hi, Can any one advise me about the actual damage caused to a frequency drive if flashed with 500 vdc from an insulation tester? I have an ABB ACS800 0100 drive (100kw) that has been flashed by someone. The drive uses IGBT modules fired from a control card, will it be the IGBT modules that...
  15. M

    High bay lighting installation help!!!

    That's a very simple way of putting it, and makes perfect sense now. When I asked the manufacturer for all and any relative information, all their technical people could advise was this 0.5A start up. What would a 'soft start' on a light fitting encorporate? Would it regulate voltage to limit...
  16. M

    High bay lighting installation help!!!

    Now im starting to get it!! I had suggested some 200watt led,s but these plasma units seem to be very efficient. Thank you very much for your help.
  17. M

    High bay lighting installation help!!!

    Sorry dark wood I don't think I'm following. The mcb,s will be ABB C10's. The manufacturer has said that there is a start up of only .5A and as they warm up they reach full power at 1.7 A. Does this not mean I can run 3 units from 1 C10? Thanks
  18. M

    Vibration motor connection

    I would agree with tony. SY cable is definitely flexible enough for shaker motors, it is the only cable I use for this application.
  19. M

    High bay lighting installation help!!!

    The units are from ceravision. Alvara 400 plasma induction. I was planning on running a three phase supply to balance the lighting across. What would be the normal install method for something like this? I know it's a lot of 3 core cables but it would be an easy install on the ground.
  20. M

    High bay lighting installation help!!!

    Hi Darkwood, Thanks for the quick reply. The units are plasma electrodeless fittings that have a soft start. 0.5 A start and then warm up to 1.7 A. My boss wants individual switching, so I was going to have 3 lights on a 10 A breaker and hence 5 breakers. Im planning on 1.5mm PVC but people...

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