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  • Users: GSI1
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  1. GSI1

    How to limit variable speed drive power draw

    Just to let you know I have used this method in the past and it works with no ill effects. The slip compansation allows the output freq of the drive to fine the best running point if you don't uenable the drive will attempt to hole the set freq. and some times will become unstable. as for ther...
  2. GSI1

    How to limit variable speed drive power draw

    Set the Current Limit on the VFD to the level you need and enable slip compansation on the VFD. This will limit the output current to the lower level. The slip compansation will limit the motor speed. If you need power loss ride through, increase the number of caps on the VFD buss. Don't...
  3. GSI1

    Machine safety.

    If you want an E stop then the contactor must be between the drive and the motor. Drives have been know to fail ON. And with the new VFDs as lons as their is power on the DC buss the drive can run. This could lead to the motor running for some time after the AC line is disconnected. If you want...
  4. GSI1

    Horsepower for hoist or lifting device

    A general rule of thumb would be 1 Hp per Ton, but it would depend on the hoist gearbox
  5. GSI1

    Variable Speed Controller for Single Phase Motor

    jOmega I checked you link go back and check again you will notice they are using PSC (Permanent-Split-Capacitor)or Shaded-Pole Single-Phase induction motors only. Both of those can be controlled with almost any household dimmer switch. Not very practical in the real world. But yes if you...
  6. GSI1

    circuit breaker vs fuse

    scud27 I noticed that you are involved in making brakers your bias is showing. please let me know where to send the next braker I find with contacts welded closed In my 30 years in the industry I have run into hundreds with considerable damage form their failure. Remember even a bad fuse...
  7. GSI1

    5kv dielectric test set, for insulation test

    electricpete In response to your last posting concerning the 500vdc megger test. First I thought the reason for the megger test on a motor is to see if the motor insalation is good or bad. If its at all questionable then pull the motor out. If the purpose is to just do the test to fill...
  8. GSI1

    Best way to control speed of lift application motor?

    The answer to your question I simple use an Electromotive Systems Flux Vector Hoist Inverter. To make it short with this motor controller combination you can control the speed of the load from 0 to 2X the motor full speed with 150% torque. With their eye for safety the shaft brake is checked...
  9. GSI1

    DC injection Braking

    Let try to help you DC Injection braking is simply passing a DC current through 2 of the 3 motor leads when the run contactor is opened. But keep in mind that the stopping torque will only be 30 to 50% of the motor torque this is usually enough to stop most loads. This should be enough to do...
  10. GSI1

    5kv dielectric test set, for insulation test

    Hello; I have always considered the min test valtage to be 2X line voltage + 1,000 volts or for 480 V system the test votlage for a megger should be at least 2,500. A 500 Volt test on a 480 Volt syten will tell you nothing and i would not use it. The peak voltage on a 480V system is 700 Volts...
  11. GSI1

    circuit breaker vs fuse

    If you want the best over current protection then always us a fuse. Even a bad fuse will open but a braker that has been overloaded just once could at any time weld the contacts and then it will never open.
  12. GSI1

    Variable Speed Controller for Single Phase Motor

    First using a single phase motor on a variable freq drive will not work. If the motor is run at a speed slower then the rated speed the start switch could pull in and the motor would run in start mode all the time. This would burn up the motor in a short time. Why not just use a. Inverter with...
  13. GSI1

    800 HP DC Motor Failure - Severe Brush Wear

    Hi just a tought on the brush fallure First the only thing i have heard about silicon is in sealed motors where it is used as the sealent for that motor then it will have a long tern effect on the brush life. but you already found the trouble, the grounded coil. depending on the motor winding...

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