Search results | Page 5

Search results

  1. S

    Stalled motor and volt free contacts on VFD.

    Then probably the best option would be to connect to PLC or smart relay trough rs232.
  2. S

    Stalled motor and volt free contacts on VFD.

    Thanks for suggestion, somehow forgot about that option. I will have to connect some DIN rail mount external relay to those transistor outputs then. I have one with 22 mA coil rurrent. Only thing is terminal 10 is used for latching push-button start up, can I use terminal 9 DOUT1 as well? Manual...
  3. S

    Stalled motor and volt free contacts on VFD.

    I think it is possible to assign only one function on to them. They are only normally open contacts so if I assign them to close when tripped then I can't use them to turn on other things using them.
  4. S

    Stalled motor and volt free contacts on VFD.

    The motor has stalled (trip name StLL) after someone tightened/overtightened screws on flange mounted gearbox. Volt free contacts on Parker SDD 650 frame 1 were still closed (assigned to close only when motor is running). They should open cause they are in series with the contactor coil of...
  5. S

    Industrial grade connector with safety switch

    Let this case serve as a severe warning for anyone else. Sooner or later accident will happen. This is not a commercial project.
  6. S

    Industrial grade connector with safety switch

    There wasn't any safety fence before as it's a completely new machine made from scratch. According to international requirements there should be a safety fence with a safety interlock switch.
  7. S

    Industrial grade connector with safety switch

    Yeah normally these things are behind a industrial safety fence. The drum mixer can be turned on only when the fence is closed. It prevents from possibility of barrel falling on to the feet, another option is to wrap around some loose chains/ropes so it can't detach itself from the rollers.
  8. S

    Industrial grade connector with safety switch

    Well it's considered bad for the VFD to disconnect the load while there is a PWM signal on the output. If I don't protect against it then I can rely on the fact that they will not unplug it while the drum is turning. They will see it when it's running anyway so I hope they will unplug it only...
  9. S

    Industrial grade connector with safety switch

    It's a horizontal drum mixer, actually two of them. There will be a VFD for smooth start-up otherwise the barrel could fall off as well as speed adjustment to adapt to viscosity of the fluid with regular automatic reversing. As I understand they want to unplug them after mixing and afterwards...
  10. S

    Industrial grade connector with safety switch

    Seems like can't find any industrial grade panel connectors with built in safety switch (when removing plug safety switch gets actuated and switches on or of contactors, relays or anything else). I need some protection against accidental or intentional removal of a plug. Interlocked commando...
  11. S

    Screening control cables

    Actually, as far as I ''know'' it's more of an issue with single core cable and steel armour, with multi-core cables it's not so significant cause electromagnetic waves induced in steel armour from two conductors cancel each-other out. How do you normally terminate the pigtail of sy cable...
  12. S

    Screening control cables

    Even when the same symmetrically arranged cable or coaxial cable is squeezed at one point then good standing wave ratio can be ruined.
  13. S

    Screening control cables

    In general ferrous metals like steel are prone to formation of eddy currents which generate heat especially at the VFD harmonic frequency range, roughly from 4kHz to 30kHz.
  14. S

    Screening control cables

    Something about different types of metals for shielding. Steel braid is good for low frequencies. http://www.ets-lindgren.com/pdf/emctd_1293_weibler.pdf
  15. S

    Screening control cables

    Only symmetrical conductor arrangement inside the cable should be used with the variable frequency drives, to avoid formation of standing waves and increased voltages. The same thing as with coaxial RF feeders (SWR meter, if reflected wave is higher than 1:1 then it gets inside the RF amplifier...
  16. S

    Sy flex armour used as cpc

    The steel braid of SY cable was never intended to be used as a screen, it's just a mechanical protection and to blow fuses when cable gets damaged (when steel braid is earthed). If you want screening for interference then you have a CY cable with tinned copper braid which must be used with a 360...
  17. S

    Earthing braid of SY cable

    The braid of SY cable is not designed as a screen against EMI as it's made from steel, only copper works as a screen (CY cable). Steel has a too high surface transfer impedance to act as a shield...
  18. S

    Misleading motor nameplate

    I think in industrial settings even low power VFD's for small motors should be with 3 phase input to reduce overall phase imbalance and increase power reserve. I don't know why have they bought several single phase VFD's.
  19. S

    Misleading motor nameplate

    Sorry, my bad the right base frequency is 50*240/415 or 29Hz. And in this case the motor power will be reduced from 0.180kW to 0.104kW.
  20. S

    Overload relay in series with contactor latching circuit- Why?

    Recently had to work on Chinese plastics dryer with an overload relay wired in series with contactor latching circuit auxiliary contacts. When the overload trips you can still turn on the motor while the button is pressed. Why is that? It should be tight before the A1 or A2 terminal I have seen...

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top