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  1. ScottyUK

    RIP Skogsgurra, Gunnar Englund

    Haven't been on here for a little while, and I log in this evening to read this news. [sad] I've learnt a great deal from Gunnar over the many years he's posted in the technical fora here, but more than that I'll miss the humour and wisdom which came across the language barrier so well. I will...
  2. ScottyUK

    Generator Droop / Isochronous Mode

    Hi Bill, Slight aside but over here intruder alarms seem to use a mains cycle counting clock rather than a quartz oscillator. I have no idea why, particularly as there's a uP onboard with a crystal of its own. Weird!
  3. ScottyUK

    Resistor repair to PCB - DIY

    If you do, see if the model numbers and/or appearance have any correlation to the European models - I've honestly no idea if their US products share the base design with the European ones. Drop me an email nearer the time, you know where to find my address.
  4. ScottyUK

    Resistor repair to PCB - DIY

    Keith, Not sure if the Bosch-branded machines are available on your side of the pond, but in my experience they're better than average for reasonable money. Ingenuity - if you're still looking for an RTV sealant, look for the 'neutral cure' types. They have a much longer curing time than the...
  5. ScottyUK

    Transformer Dissolved Gas Analysis

    Ethane is usually a sign of a fairly high temperature fault within the transformer. A competent oil lab should also be providing advice on the transformer's condition based on the gas signature - speak to your lab and ask for some help interpreting the data. Of far greater interest than...
  6. ScottyUK

    Motor Schematics (Large Motors above 4MW)

    Motors in that size range might well be switched by breakers, not contactors - the control schematic may have more in common with a distribution transformer feeder of similar rating, with the obvious difference of a motor protection relay rather than a transformer relay.
  7. ScottyUK

    Can IP-66 enclosure be air tight?

    An Ex'e' enclosure relies upon reinforced insulation and increased creepage and clearances to prevent an internal ingition. If something does ignite a flammable atmosphere within the enclosure then the enclosure will rupture. If you want to withstand that scenario then you need an Ex'd'...
  8. ScottyUK

    UPS on internal bypass, rectifier input still drawing 90A

    If there's an isolating transformer fitted internally upstream of the rectifier then you're possibly looking at magnetising current for the transformer. If it is then it's almost purely reactive with no load from the rectifier on the secondary.
  9. ScottyUK

    Isolated system

    There are number of UK socket variants with round or T-shaped earth pins, or earth pins rotated 90° from their normal orientation, but none of these have a purpose defined in regulations - they are special-purpose types used for purposes defined by the user. It's not clear from your question...
  10. ScottyUK

    Types of mounting on DIN rail

    Hi Keith :-) G-rail was once very common in the UK and used with the very popular SAK series of terminals, it's still popular but perhaps less so. I agree that TS35 is the best option in this case.
  11. ScottyUK

    Types of mounting on DIN rail

    There are two basic types of DIN rail - 'top-hat' rail, Weidmuller code TS35, or 'G' rail, Weidmuller code TS32. The heater in the top right photo of your link is on TS35 rail.
  12. ScottyUK

    Heat dissipation in IP 67 Enclosure

    From practical experience, yes you have a serious problem. You will need either active cooling or forced ventilation. If you are outdoors then you need to consider heat gain from the environment - ambient air temperature, and the effects of insolation (solar gain) unless you're mounting it...
  13. ScottyUK

    UPS static bypass vs STS

    Are the two UPS’s locked in phase? If they are then difficult to say which will be fastest, if they’re asynchronous then the internal SBS will probably be faster as the output phase-locks to the bypass supply.
  14. ScottyUK

    Type F plug to which I can connect my own power cord

    H07 cable is a high temperature rubber. Is there a reason why the more common PVC-insulated type which is commonly used in European pre-wired cordsets isn’t suitable?
  15. ScottyUK

    Ex "ec" Motors

    Ex 'ec' is the rebranded Ex 'n' which you're probably familiar with. Ex 'e' is now Ex 'eb' Ex 'eb' motors are suitable for use in a Zone 1 or Zone 2 environment. They must be protected with an overload certified for the purpose - a very quick curve, close to a Class 5 response, which isn't much...
  16. ScottyUK

    Allam Generator

    Got any photos Graham? Allam made little portable machines for construction sites, they were pretty basic with either capacitor-stabilised or self-excited AVR-type alternators. As a company they were a small operation, I don't expect they had many employees and not much chance of finding a...
  17. ScottyUK

    1/4 HP AC motor with CE declaration of conformity

    If you're selling into the European motor then fit a European motor. The maintenance guys will curse you if they ever have to replace a NEMA pattern motor over here in Europe. We've been though this for a few explosion-proof NEMA motors on our site which arrived as part of pumps sourced from...
  18. ScottyUK

    Power transformer bushing test tap broken

    Bill - how would you extract it and reinstate the connection to the internal foil layer?
  19. ScottyUK

    Looking for design standards regarding naming convention of signal/control wiring

    Hi Hoxton, BEBS-12 is now ENATS TS 50-19, yours for £45 from the ENA.
  20. ScottyUK

    Fault current flow in Generator winding

    Rotor heating is a problem from negative phase sequence currents circulating a double line frequency in the rotor forging. Zero sequence currents would also cause heating, but aren't seen with the generally-accepted delta winding. With the delta wound transformer, zero-sequence currents are...

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