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  1. 3-Phase motor (voltage issue)

    General Electrical Discussion
    I haven't had much experience troubleshooting 3-Phase motors. Recently received a service call to look at a meat grinder that uses a 3-Phase 120/208V motor. The customer stated that they had someone out there to repair the machine because the motor was not running just humming.The tech stated...
  2. KVA vs. KW for motors

    General Electrical Discussion
    I was doing some research for a customer who is installing a hot tub and I just wanted to be sure we were not going to overload his existing electrical system. (I originally wanted to do a load calc which included a number for his existing AC unit.) I found this quote below from an old thread...
  3. damp locations

    General Electrical Discussion
    I have a customer who wants to install some paddle fans under her front porch which is considered a damp location by the NEC. (It is roofed but not enclosed.) Is this acceptable? Would the paddle fans have to say suitable for use in a damp location as required for a luminaire? 410.10 (2008 NEC)...
  4. running a 3 phase motor on a 2 phase, or single phase, system

    General Electrical Discussion
    anyone have any ideas on what is the best way to run a 3 phase motor on a 2 phase or single phase system?
  5. Power for 3 motors

    PLCs, VFDs, Motors and Controls
    Hi guys, Im looking to connect power for 3 mixers all in one location. The first is 50 Hp the second is 5 and the third is 1/2 HP. All 3phase 600V. The building has a 100Amp service and a splitter I can tap off of. I have to run power 150 feet away from the splitter. Would it be better...
  6. Disconnect for VFD - Does it have to be within sight of VFD??

    NEC Code Forum
    For years in industrial facilities, we have been able to disconnect a motor back at the MCC (and use LOTO) for service. We usually do this when the motors are located in Electrically classified spaces. But also in pharmaceutical where the fewer boxes & conduits the better. We were recently...
  7. My first Post

    PLCs, VFDs, Motors and Controls
    Hello guys, Im working with Baggage handling system that is running with S7-400 siemens plc and we are using "SEW's Frequency Inverter to control the operation of some motors. I have a problem with one frequency inverter from MOVITRAC 07 series. when the motor is running the inverter is giving...
  8. Homemade Testing Tools

    Tools, Equipment and New Products
    Alright members, time to whip out those homemade troubleshooting tools. Seems that there is always something on our mind at the end of the day that we should make to make things that day 'so much' easier. Share with us tools you have made that have made troublshooting a breeze or tools/equipment...
  9. three phase induction motor

    PLCs, VFDs, Motors and Controls
    Hi everyone, I am working in a power plant in India( frequency of voltage is 50 hertz) and this is my first project.I have to install induction motor (3 phase,132 kilowatt and 1.5 Kw motors),This my first experience with these motors and I want know about the pre-commissioning trial of these...
  10. Float switch with start stop override

    PLCs, VFDs, Motors and Controls
    My shop teacher would like to find a ladder diagram for a float switch with a start stop button override. He is not able to draw a diagram that would work. Please help with this. Edit: To make it more clear he wants it to be that the float switch does not have to be closed for you to turn the...
  11. Variable frequency drives

    Commercial Electrical Forum
    I have always found variable frequency drives to be particularly challenging. I found an excellent article on troubleshooting these drives that I would like to share. It explains a very efficient method that begins at the motor and systematically works back to the electrical source. I recommend...
  12. How do i choose a circuit breaker for different loads?

    NEC Code Forum
    Please help me with this question? I have a four (4) three phase motors 15 Amperes each one, they must be protected each one by a circuit breaker, also i have a three phase transformer 150kVA also protected by a circuit breaker. These circuit breakers are connected to a 480V - 3PH bar inside a...