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Crosland

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Everything posted by Crosland

  1. Crosland
    Yes. At low speed there's very little back-EMF being generated and the motor will draw close to it's stall current. PWM tends to use pulses of full voltage which exacerbates things. The more delicate brushes do not like the higher peak current at the start of each pulse, or so I have read, I believe, from one of the 4mm fine scale societies findings. At higher frequencies, the motor inductance makes the supply look more like DC at a lower average voltage (same holds for core motors too).
  2. Crosland
    Definitely not ALL :)
  3. Crosland
    Every DCC decoder is a PWM controller, so PWM and coreless do mix, but... You need a much higher frequency PWM than the typical old-school PWM controller which may have derived the frequency from the 50Hz mains supply. Modern DCC decoders can be 10s of kHz. How that would work on an analogue layout with a central controller, I can't answer.
  4. Crosland
    It's not really about actual stalling which, as you say, is unusual. A loco being driven hard, that is heavily loaded, will slow down. The Back EMF will decrease and the motor current will increase. The "stall current" is the absolute worst case limit of this process (maximum voltage applied, very low speed). Unless the loco itself is very heavy and has very good grip, the wheels are more likely to slip before you reach the stall current.
  5. Crosland
    You could have used a £5 multimeter to measure the current from the power supply to the system.
  6. Crosland
    Not directly answering your questions, but Remember 8k is not double the resolution of 4k. Test prints are as much about calibrating your use of the printer, e.g., supports, position relative to the bed, ...
  7. Crosland
    There's a supplementary fee of 16p for PO drop off on some services, see https://www.royalmailchat.co.uk/community/viewtopic.php?t=110728
  8. Crosland
    The supplied transformer (it requires AC to work, a Switch mode PSU is no use) results in a stupidly high track voltage. I would avoid it and spend more money on something better, like the various Roco items you often see (or used to, at least) split from sets.
  9. Crosland
    It's a percentage of the total sale price (inc. delivery) owed to the seller. Royal Mail do not have any special claim to it. What the seller charges, and who they engage to deliver (doesn't have to be RM), are entirely the sellers business.
  10. Crosland
    We do generally recommend the SPROG II for programming and running in the smaller scales, and the SPROG 3 for larger scales, but the SPROG II can be used with a 15V supply. There could still be an issue, however, if the current draw is too high. The problem I referred to was actually with a 15V supply. Andrew
  11. Crosland
    I have had a customer report the same issue with the DCC fitted version of the 92, 37 and the Deltic. No resolution as yet. Andrew Crosland sprog-dcc.co.uk
  12. Crosland
    Don't use the GSP!
  13. Crosland
    Discrete component package types refer to the length and width. You need an accurate measurement, but I would suggest something like EIA code 2824 or 7260 metric. The 2824 is in thou of an inch and designates 0.82 x 0.24. The metric size is mm and designates 7.2 x 6.0 mm. That leads you to https://uk.farnell.com/avx/f751a477mrc/cap-470-f-10v-20-2824/dp/2408402 which is 1.2 mm high. The height can vary with value, voltage rating, etc, ...
  14. Crosland
    Filing destroys any coating and just leads to the bits corroding away. You end up re-filing until there's nothing left.
  15. Crosland
    I'm still here almost 20 years on :) I do (kind of) have a succession plan should it come to that. Still (occasionally) supporting original products. Andrew Crosland sprog-dcc.co.uk
  16. Crosland
    It's called "enshittification" First, they are good to their users; then they abuse their users to make things better for their business customers; finally, they abuse those business customers to claw back all the value for themselves. Then, they die. Wiktionary defines it as "The phenomenon of online platforms gradually degrading the quality of their services, often by promoting advertisements and sponsored content, in order to increase profits"
  17. Crosland
    Take pictures of the package as you package it.
  18. Crosland
    Potentiometer v. rotary encoder. You (or manufacturers if they wanted to) can get around it by not allowing the throttle to fully take over the new loco until the pot has been adjusted to match the current speed (which the command station will need to have stored). Maybe the EZ command does that.
  19. Crosland
    The term "DC" covers a multitude of sins. Is it really pure DC or some form of pulsed supply or half-wave rectified + DC, or, ...? I would thoroughly test a module on the "DC" supply before committing to anything.
  20. Crosland
    That was probably someone else in a van, not the regular postie. That's how it works round here for timed services.
  21. Crosland
    Short answer Yes, no (of it being there). Longer answer: It is a suppression capacitor for analogue use. You are correct that it may interfere with BEMF but all that I've seen on the subject suggests that Zimo decoders are generally tolerant of leaving the cap connected.
  22. Crosland
    Collection is still free until later this month. It was extended last time it was due to expire. There's a footnote on one of the pages when you book and pay on line with the exact date. RM reduced the on-line price of small parcel 1st class earlier this year (from £3.95 to £3.69). I suspect it may be in anticipation of adding the collection charge back on.
  23. Crosland
    Online or at the PO? Online, small parcel is the same price (£3.29) up to the 2kg limit. Some services (e.g., special delivery) vary by weight. None of the services are £3.45 for 1Kg
  24. Crosland
    Link doesn't work, simply goes to http://here
  25. Crosland
    How about a combination of 3D printed and more easily fettled metal parts?
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