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  1. eemotor

    Estimating the Life of Motor

    Remember to also include bearing life in your equation.
  2. eemotor

    Multispeed motor issue.

    Fernando, The motor may be just fine. Multispeed motors may exhibit higher no load current in low speed than high speed due to high magnetizing current required by the low speed connection.
  3. eemotor

    Decelerate 2 Speed Motor by Connecting to Low Speed Winding

    Hello All, An interesting idea was raised today by my colleague. Let's say you have 3 phase, 2 speed (3600/1800 RPM) consequent winding motor and you're running it at no load at 3600 RPM. Shut the power off, reconnect for the lower speed and energize. At point of energizing the low speed...
  4. eemotor

    What computer hardware is working well with working with 100 mb files?

    It appears that SolidWorks has certified driver version 8.163.1 for Fire GL V3100 for use with SolidWorks 2007.
  5. eemotor

    basic question about motor

    Sorry, wrong link in the previous post. The correct on is thread237-97642
  6. eemotor

    basic question about motor

    kien123, If you'd like to find out more about what happens to a DC motor when field is removed and armature circuit is powered, take a look at thread181-27567 .
  7. eemotor

    Large Motor Testing Facility

    I think in a back-to-back test with 2 induction motors, the two motors are coupled together through a gear box. One motor runs at rated speed, the gearbox is adjusted so that the second motor (which will be generating power) runs at the same exact speed. I believe at that point a switch is...
  8. eemotor

    Large Motor Testing Facility

    I went ahead and contacted EASA. They also suggested Schulz Electric. Schulz Electric can't sustain the load of a 1000+ HP motor for an extended period of time. We also can't test the motor back to back as we won't have another motor of similar rating available to do a back to back load test...
  9. eemotor

    Large Motor Testing Facility

    Hello all, I've been doing a bit of a search online for companies that deal with testing motors in north east US. In particular, I'm looking for a place that can test (heat run) 1000+ HP @ 3600 RPM continuous. So far, several places that I found have the power required but can't sustain...
  10. eemotor

    [b]Motor efficiency and a dynomometer[/b]

    Often when testing for motor efficiency we use a torque tranducer between the motor and the generator to measure power output (torque and speed) at the motor's shaft. However, the transducer's can get a bit pricy.
  11. eemotor

    Motor Vibration

    Sometimes your power supply may also cause 2x line frequency problems. Whether it's harmonics or line unbalance as the cause, we've seen 120Hz (US) at high levels before. Often going on motor-generator set seems to reduce the 120Hz level.
  12. eemotor

    Calculate Phase current

    In a delta connected transformer, each line is connected to two transformer phases. Thus, each phase current is equal to Iline/sqrt3. <br>You can also find out the phase current by using VAphase/Ephase
  13. eemotor

    Source for 36,000 RPM electric motor

    Why not take a standard 3,600 RPM induction motor and couple it to a 1:10 gear ratio transmission?
  14. eemotor

    Insulation resistance - domestic and industrial

    Polarization index is still used to check condition of motor winding insulation. The capacitive charging current usually decays to a negligible value before the first measurement at 1 minute is taken. There is also absorption current that's present. However, this also decreases to nearly...
  15. eemotor

    Dip Brazing Aluminum

    It struck me as being a bit strange when another engineer suggested the use of silver brazing with aluminum. I didn't check the actual melting points of the alloys but I know that Aluminum melts at approximately 660 C while Silver melts at about 1080 C. So it didn't appear correct to me that...
  16. eemotor

    Dip Brazing Aluminum

    Hello All, I have an aluminum (6061) disk with slots cut into it. Aluminum fins (also 6061) will be inserted into the slots and joined using dip brazing. As far as I know, dip brazing process involves a bath of sodium, potassium, lithium and aluminum. Has anyone ever heard of using...
  17. eemotor

    Air gap and starting current

    I recently ran into an issue of how does the air gap of a 3 phase induction motor relate to the motor's starting current. Even though many other performance characteristics of the motor change as well, the starting/locked rotor current was my focus. It appears that with a larger air gap the...
  18. eemotor

    Wheatstone Bridge - Where can one buy it?

    ScottyUK, thanks for the suggestion about the digital bench meter. I just realized that we have a Fluke 8842A bench multimeter with a 2 and 4 wire input for resistance measurement. It's accuracy is .008% @ 1 year after calibration with just the 2 wires on 2kohm range. Looks like we might not...
  19. eemotor

    Dynomometer

    Yes, I've seen some vacuum cleaner motors claiming 4 or 5 HP from a 120V 15Amp circuit. Is this a peak power representation or continuous duty. If continuous duty, how's that possible to produce 4 -5 HP from 120V @ 15A? It would seem to me that even with PF of 1 and eff of 100% the max you...
  20. eemotor

    Wheatstone Bridge - Where can one buy it?

    The expected resistance value is going to be approximately 300 ohms. One additional question that I ran into is the accuracy of the apparatus that I was looking into buying. It was .1 to .2% which seems great to me and will be sufficient for our measurements but I don't know how it rates...
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