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  1. wired1

    Distributed Control Systems - DeviceNet & SDS

    Ohmboy: the protocol can bought by anybody who wants to produce compatible products, although AB may their own version which may have proprietary components to it. see http://www.odva.org
  2. wired1

    400 hz m-g set

    I'll try anything at this point . . . By the way, its for my company - not me.
  3. wired1

    Distributed Control Systems - DeviceNet & SDS

    I don't believe SDS and DeviceNET are compatible in either their signal levels or physical media. While not having worked with SDS, I found that I could make large deviations in the physical media of DeviceNET and it still worked. Don't expect to get the same speed or distance if you use a...
  4. wired1

    400 hz m-g set

    I understand your point of view. We want to do overload and rupture current levels that will call for 8 to 10 thousand amps, however. Also, the kva is a factor - 300. The static mfrs. hesitate when I give them those numbers.
  5. wired1

    400 hz m-g set

    I'm in the market for a 400hz m-g set. Anybody know any good sources? The intended use is for in a testlab.
  6. wired1

    Induction motor speed contollers vs Variable Frequency Drives

    The ASD looks like an eddy current clutch. I had some limited experience with this type of drive on a long conveyor that was driven by two motors. the clutch helped balance the motors to eliminate any surging as they reacted to the varying load. As far as I know, a VFD can handle any control...
  7. wired1

    Drive Size: Ratio of Inertia's

    if the inertia of the motor is used as a baseline, then the ratio serves as a convenient way to gauge the ability of the system to respond to changes (ie. ability to accelerate within a reasonable time). i have seen this ratio advocated by other manufacturers but i believe to be a rule-of-thumb...
  8. wired1

    Diode supression of relay back emf

    Note that the use of diodes or suppressors on dc relays is considered mandatory enough that some manufacturers design them into the relay.
  9. wired1

    Need camera sys to capture motor name plate data

    A tip on file size. look for software that will let you save images in .tif or .gif format. these take a lot less space. i think the above mentioned photo editor can do it. (never save images as .bmp - that's the worst on file size)
  10. wired1

    Burst Modulation

    This sounds like a technique also known as "bang-bang" (on-off) control; commonly used to control a resistive heater. It is used on electric valve actuators - ac and dc both. The bang-bang controller is a PIC chip that "bumps" the motor while a feedback pot monitors the...
  11. wired1

    Nonincendive Wiring

    BradJ To your previous question what NEC calls a device that produces an arc in normal operation, is precisely as you have surmised, a switch. Sounds like lawyer-speak, but think about it - pushbuttons, relays, dc motors with their commutators, all fall into this category.
  12. wired1

    I need a digital 4-20mA controller

    I have used Eurotherm controls to do this. The 2416 is a popular one. But any of the instrument companies would have a product that would do it.
  13. wired1

    high precision drive for solar telescope

    my comments follow: -resolution: With a stepper or a servo, it will be possible to achieve the resolution but the accuracy will be difficult. Will the mechanical system be able to hold to the .5 arcsecond level? -digital encoder: How is the system set up/aligned/reset? If a one-time-only...
  14. wired1

    high precision drive for solar telescope

    I think the 100 rpm parameter was given as a minspeed to minimize the effects of cogging or “torque ripple” from the motor. You might ask the source of that info to give his basis for it. Maybe he thinks your app requires a low speed performance level that it really doesn’t. I would think...
  15. wired1

    Turck Sensors ?

    PUMPDESIGNER Years ago, I used a lot of Turck for Industrial Control applications. They had a good reputation and were a favorite choice. Later, they became partnered with Banner, and perhaps a different management philosophy has prevailed. I definitely agree with CHDean that they need to...
  16. wired1

    determining values for starter capacitors

    pcb22000: My statement about the torque of the motor actually refers to a "capacitor run" motor. Please pardon my error on that point.
  17. wired1

    determining values for starter capacitors

    There may be standard designs that all the motor mfrs use but I'm not sure. The best way is to contact the mfr. I can tell you that value of the capacitance will affect the torque of your motor. Also, another rule says to use a voltage of 1.5 x the highest the voltage the motor sees. The...
  18. wired1

    Machine safety.

    Lawtons: Take a look at NFPA 79 - Electrical Standard for Industrial Machinery. The standard from Australia makes perfect sense to me. Years ago, I cut my teeth on trying to stop a servo axis that was moving a high inertia load at a pretty good clip. I started out by simply cutting the power...
  19. wired1

    What could make a motor not achieve full RPM's?

    question on previous post . . . DKB1943: Is your statement about cap aging a general statement for all types of construction (metalized film, polypropylene, etc.), or are some types better than others in this regard? thanks in advance for any feedback . . .
  20. wired1

    machine sychronisation problem

    I'm unfamiliar with the PLC you have. Are you trying to do this strictly with PLC logic or do you have motion control card? If you have a motion card, it should be do-able.

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