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  • Users: 60hzhmmm
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  1. 60hzhmmm

    How much heat comes from an electric motor

    marko333: You do realize that 45kW will be dumped in the "area" of the motor. If the motor is running a leather stacker then all of the motor's consumed energy will be dumped in the immediate area. This is often messed up when people are doing air conditioning calculations.
  2. 60hzhmmm

    UL Panel Shop Certification

    Kimatek: I may.... jabartos and amptramp are correct there are other "labs" I've used FM labs (Factory Mutual) in the past to good effect. I can explain in detail the listing of an electrical/electronic control device but u did state UL panel shop which is of course different.
  3. 60hzhmmm

    lithium-metal-polymer batteries

    Anecdotal: The first company that made lithium batteries, burnt down....
  4. 60hzhmmm

    UL Panel Shop Certification

    KIMATEK: Of course UL is an organization set up to extract lots of money under the guise of saftey... So.. To get "UL panel shop" certification get out your wallet and contact UL. Essentially you take several short courses from them,(which you pay for), where they go over what is...
  5. 60hzhmmm

    MOV Failure Mode

    paulcet: I have seen them fail "gone" two bare leads standing up off the board... buzzp: I'm still a little confused... If you are talking only about anti-kick back on the relay coil and it's DC why are you not just putting a reverse diode across the relay and being done with it?! I...
  6. 60hzhmmm

    Diff between RMS & True RMS

    logbook: For a while the "BEST" rms meters were actually just a resistor that converted anything that came by, (crest-factor be damned), to heat. The resistor's temperature was monitored acurately with great detail and calibrated to "true" rms. A pretty clever fundamental...
  7. 60hzhmmm

    A/C efficiency

    rmarotta: If you have room for hot water storage,(like one or two more hotwater heaters), that would give you the biggest bang for the buck. By far! There is a company that makes hotwater extraction systems(Thermoastor?) that will allow water upto about 200F to be extracted. Essentially the...
  8. 60hzhmmm

    A/C efficiency

    rmarotta: Yes a VFD will work nicely. You will want to control it to head pressure. You need to be a bit careful here.... Dot your eyes and cross your T's. Make sure the oil pressure remains viable. Too slow equals no oil pressure. As the VFD slows things as the expansion valve throttles...
  9. 60hzhmmm

    The difference b/w voltage imbalance and phase loss

    Ah sudher... With respect to three phase systems, PHASE LOSS is the total loss of one of the three phases. Often this results in the destruction of any loaded three phase motors in short order as their torque drops significantly, so they slow significantly, which increases the current thru the...
  10. 60hzhmmm

    Touch Switch

    Hi raq23: I don't know if you're doing a one-up or not but I caution you on touch switches that work thru mechanical relays.. There are lots of gotchas lerking about. As a kid I once made one. I gave it to a girl friend she loved it till she leaned a metal milk crate next to it and it...
  11. 60hzhmmm

    Electrical Enclosures

    buzzp: Thanks man! I'm always interested in enclosures. BTW I've used: http://www.fiboxusa.com/ several time to good effect.
  12. 60hzhmmm

    Control Cab Cooling

    djw2k3: The vortec coolers busbar linked are very effective. And very reliable. HOWEVER, they require constant uninterrupted plant air. If the plant air stops often a totally unrelated "thing" controlled by a different gang,(the ones with pipe wrenches), you get puzzling electrical...
  13. 60hzhmmm

    Diff between RMS & True RMS

    buzzp hits the nail on the head. You can certainly have an RMS meter that is exact only if the measured signal is a sinewave. If you aren't measuring sinewaves you better have a "true" rms meter. That's the industry standard nomenclature.
  14. 60hzhmmm

    hard disk failures

    chiplonkar: You have not clearly stated whether or not the drives have been "damaged" or not. Drives are very very dependable these days. Far, far more dependable then the failure rate you are experiencing. They can be mounted in any position generally except upside down, this will...
  15. 60hzhmmm

    kW vs. kVA and power factor

    jfriddel: In my limited experience there is more to this than efficency. I have never seen an engine used at it's "rated" horsepower as a prime mover for a generator. I believe that the usual engine ratings are peak momentary output. (typical specsmanship) If you were to run at that...
  16. 60hzhmmm

    measuring costs on compressors star

    kwaka: You have posted this to the wrong forum. You should've sent it to the POWER/MOTORS forum. Where, if you are contemplating the use of a STAR-DELTA starter you will find very little positive support as STAR-DELTA starters are generally less effective than across the line starters...
  17. 60hzhmmm

    motor control

    cabber: Does it always run backwards first(ALWAYS) or occasionally? Since this is a DC motor could it be the commutating/brushes in a position where the initial torque is briefly in reverse? I would expect this to be an occasional thing whereas a tach thing might be consistent.. Just a guess.
  18. 60hzhmmm

    Randomness, How?

    amptramp: Great link there to Formilab! It sucked me in totally. Very well done. Thanks for the link.
  19. 60hzhmmm

    Electrical Enclosures

    Yeah buzzp post the links... DO it Do It do it! thx
  20. 60hzhmmm

    Randomness, How?

    One of the truly random things in nature is radioactive decay... If you set up a slowly decaying isotope and run, say, a 16 bit counter that you read whenever a decay is detected you'll have a random number.... Fred Saberhagen's entire Beserker series is even based on this. Great SiFi.

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