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  • Users: TMD
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  1. TMD

    IEC 60664-1 and IEC 60664-2-1

    IEC 60664-2-1(1997) is a technical report that is supposed to refer to sections in IEC 60664-1(no date specified). I have IEC 60064-1(2007), and the sections stated in 60664-2-1 do not exist in 60644-1. Has anybody come across this and have a document that maps sections and tables in 60664-2-1...
  2. TMD

    Source of supply - Hydraulic hoses

    I'm looking for a supplier of hydraulic hose assemblies that are a bit unusual: - working pressure 5500 psi, burst pressure 4x - 3/4" nominal - nominal o.d. 28 mm [1.10"] - 80 C working ambient - 13 m (42 ft) (can be spliced, and exceed the nominal od) - PTFE core - 316 SS braid...
  3. TMD

    Electrical/optical connectors - source of supply

    I am looking for some military connectors, MIL-C-38999 Series III, but there are a few wrinkles. I have them on order with a supplier now, with a delivery of 20 weeks...I need them in 8 weeks. And to make matters worse, the shells are stainless steel and I'm using optical contacts in these...
  4. TMD

    NEC ampacity and ambient temperature adjustment

    The NEC (NFPA 70) has an equation for converting cable ampacity at 40 C to ampacities at different ambients (Section 310). The equation has a Delta TD = Dielectric Loss Temperature Rise. Where can I find values for this factor? I suspect it's in the IPCEA document referenced, but I don't have...
  5. TMD

    Short duration pressure impulses

    Anyone have any experience with short duration pressure impulses and the effects they have on steel enclosures? I'm trying to make a "scientific" connection between strain and pressure pulses of less than 1 ms duration. Empirically, a steel enclosure can withstand, without permanent...
  6. TMD

    Clearance and creepage in oil

    I have read few standards (only one I can think of) that specifies clearance and creep distances in oil filled equipment. All the standards I have read on medium voltage equipment (15 kV), both NA and European, specify spacing in air with no mention of oil (or other fluids). Anybody have any...
  7. TMD

    Arc pressure wave

    Can anybody offer any direction on calculating the pressure wave that would be produced by an electric arc? As an example, if I have a 10 kA fault current that is cleared in 1/2 sec, is it possible to calculate or are their general guidelines for determining what the pressure will be?
  8. TMD

    Ground plane for test lab

    Can anyone direct me to reference material for designing a grounded floor and earth ground for a high voltage (100 kV) test lab? Something on the web is best of course.
  9. TMD

    Explosion pressures

    A non-electrical question for electrical engineers (we seem to know something about everything). Anyone know where I can get a chart (on the web preferably) showing differences in pressure expected when igniting ethylene at different ambient pressures? That is, if in a certain container we...
  10. TMD

    Magnetic "flap" valves

    I'm looking for a source of relief valves to control air flow at low pressures. I've seen valves that have a flap that is held closed magnetically and opens at very low pressures, 4-6" of water. Anybody have any suggestions?
  11. TMD

    Oil and EPR insulated cable

    We have some 6.6 k machinery that has 15 kV EPR insulated jumper cable inside, used as short interconnections. We want to pressurize/ventilate the equiment with instrument air which will have some oil content. EPR is not great with oil (rated fair to good by cable manufacturers). Does anybody...
  12. TMD

    E field in a coax

    I asked this ages ago and got a response refering to surface integrals and Gauss's Law and good stuff like that. Well I struggled and can't cast my mind back 25+ years to figure that out again. So I'll ask again, and hope someone can respond (preferably with an equation or two). What are the...
  13. TMD

    European wire designations

    Can anybody direct me to a standard, or better, a website, that will explain the differences between European harmonized wire designations, like H07V-U, H07V-R, H07V-K, H05V-K, H07G-K, NSGAFou...you get the point.
  14. TMD

    European wire designations

    Can anybody direct me to a standard, or better, a website, that will explain the differences between European harmonized wire designations, like H07V-U, H07V-R, H07V-K, H05V-K, H07G-K, NSGAFou...you get the point.
  15. TMD

    Cable termination

    When terminating a medium voltage cable, (15 and 35 kV, EPR), any damage (cuts, nicks, slices) to the EPR requires that the cable be cut back and you start again. However, in some situations, this may not be possible due to limited cable length. Has anyone ever tried to repair damaged...
  16. TMD

    Metric compression lugs

    I'm in Canada and am looking for metric compression lugs. We have found very few suppliers on the net, so was wondering if anybody has any leads? Specifically, we are looking for 2 hole lugs for 70 sq. mm cable.
  17. TMD

    Insulating spacers for cable

    We need to route three conductors (#2/0 AWG) of a 3 phase circuit in trefoil and are looking for a method to control the lay of the cables. I suspect that there are insulating spacers or "spiders" that are used for this purpose, but am having trouble finding them. Anybody know of a supplier...
  18. TMD

    Cable glands and single core cables

    IEC 60079-14 requires that for cables directly entering an enclosure greater than 2 liters and with a source of ignition need to be sealed in some manner. Section 10.4.2 allows compound sealed cable glands. My question is, is a compound sealed gland required for a single core cable? Seems to...
  19. TMD

    Medium voltage wire

    I need to connect some bare, live parts in electrical equipment and would like to use insulated wire to do it because space is limited. Problem is, voltage to ground is 7200 V. Because distances are short, shielded cable is not practical. Anybody know of a source for such wire? I'm looking...
  20. TMD

    Cleaning EPR

    I've seen a variety of products recommended for cleaning EPR cable insulation prior to installing stress control sleeves. Anybody have any personal best recommendations? Or products that are recommended by others but are best avoided?

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