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  1. Lucien Nunes

    Triton shower problems

    No. A heating element is a resistance so it takes a current strictly proportional to voltage. If there is high resistance at the switch or RCD, the voltage at the shower will be reduced and the current will be reduced in proportion. However, as we discussed in a recent thread about the effects...
  2. Lucien Nunes

    Use of Wago boxes for spur

    The standard rating of Wago 221-series connectors is 32A. However, to achieve the very low temperature rise specified for MF applications to BS5733, the rating is reduced to 20A. The minimum current rating for any accessory used in a ring final configured in the normal way with accessories to BS...
  3. Lucien Nunes

    Readings from a multimeter

    It sounds like there is a fault in one armature coil. With a simple 2-pole motor like this, testing between opposite segments on the commutator reads the parallel resistance of two circuits though the armature, each containing half the total coils. With an intact armature, the total number of...
  4. Lucien Nunes

    110 V Motor Question

    OK right, so the cable from the NVR seems to be 4-core. If we number the three white terminals in a row 1 - 3 we have: 1 - brown switched line from NVR > two blacks into motor 2 - grey switched neutral from NVR > white into motor 3 - black switched line back to NVR hold coil via thermal...
  5. Lucien Nunes

    Single and three phase current capacity and voltage drop differences.

    If you like, you can visualise a balanced 3-phase load as three independent star-connected loads each of one third the power, operating from 230V as you mention, to discover the line current. However the convention is to divide by sqrt(3) and use 400V which will give the same numerical result...
  6. Lucien Nunes

    110 V Motor Question

    The capacitors charge and discharge 100 times per second (on 50Hz AC). Some residual charge might be left on a disconnected capacitor but when the motor is functioning normally, no capacitor will be left open-circuited at rest. We don't need to play guessing games. We just need to trace...
  7. Lucien Nunes

    Power station control room/turbine telegraph

    Mark and I talk about this stuff all the time. Now that I'm not really in a position to enjoy playing with hardware it's good to share stores and ideas with someone who thinks along exactly the same lines.
  8. Lucien Nunes

    110 V Motor Question

    I see what looks like a 5-core cable entering the motor - brown/black/grey/blue/earth. Obviously this is more conductors than needed simply to operate a motor in one direction and speed, so: Please can you confirm there is no other control functionality from the control box? Can you confirm the...
  9. Lucien Nunes

    110 V Motor Question

    Start capacitors can have wide tolerance, that difference in value should not be a problem. Faulty caps are usually either open circuit or short circuit. The fact your motor does nothing points elsewhere. I'll reply in full later if I can
  10. Lucien Nunes

    Star to Delta conversion

    If one coil is reversed then you have what is basically a shorted transformer pitting two phases of the of the incoming supply head-to-head with the third. So long as you proceed as above, pairing each of the wires that had been attached to the star point with another that had been a line wire...
  11. Lucien Nunes

    110 V Motor Question

    It's a little hard to follow exactly what you have there. It is likely to be a capacitor start and run motor, in which the main winding is connected directly to the supply, the auxiliary winding is connected via the run (smaller value) capacitor, and the start (larger value) capacitor is...
  12. Lucien Nunes

    Ring Final Circuit (RFC) versus Radial. Yes, again.

    As mentioned above, a 'series arc' in one leg of a ring won't really arc because there's hardly any voltage across it. If it doesn't arc, the AFDD won't find it. If it does arc, the AFDD will react and disconnect it. A loose terminal in a socket will arc on a ring just as as on a radial and the...
  13. Lucien Nunes

    Ring Final Circuit (RFC) versus Radial. Yes, again.

    Post No.28 above is important, because it debunks one of the most common incorrect arguments used against the 2.5sq.mm. 32A ring. It is often said that if one leg becomes disconnected or the circuit is badly arranged leaving all or most of the 32A load on one leg of 2.5, that cable presents a...
  14. Lucien Nunes

    Have the rules for ring mains changed over the years?

    Sorry, some of that stuff in post 53 is nonsense or applies just as much to radials as to rings. I can't be bothered to unpick it for critique.
  15. Lucien Nunes

    How many phases? And another Lucien grumble: 'Amps Per Phase'

    When I joined this forum a decade or so back, there was a discussion going on about a welder that was connected with a 3-core cable to L1, L2 and earth of a 3-phase supply, operating on the 400V present between L1 and L2. The advantage of choosing 400V is the reduced current requirement. My own...
  16. Lucien Nunes

    Have the rules for ring mains changed over the years?

    I really don't know what the point of this thread is. But I do know: A final circuit is one that feeds a load or loads, rather than another level of distribution When the ring final circuit was introduced in 1947, it was acceptable and correct to call it a ring main, and the term was used in...
  17. Lucien Nunes

    Weird?! Neutral-earth fault

    Not by any means a certainty. A reading of 0.00 MΩ displayed on an insulation test could be as high as a few kilohms, or over over 10kΩ if you allow the +/- one count. E.g. 5kΩ= 0.005MΩ. With the few volts likely to exist between neutral and earth, the resulting leakage current is likely to be...
  18. Lucien Nunes

    Neutral - earth continuity understanding or misunderstanding?

    Over the last few days, I have stumbled across a number of threads that seem to point to a prevalent misunderstanding. Either that, or I have been misunderstanding the intention of the posters. I'm not linking any threads here as I don't want to call anyone out for this specifically. In each...
  19. Lucien Nunes

    MEET on BBC TV (the Museum of Electrical and Electronic Engineering)

    One all.
  20. Lucien Nunes

    MEET electrical museum facebook page now up

    Hi Pamela Thanks for your message. We're not actually open yet, just looking for premises. What you saw on The BBC programme was our 'play area' in one of the storage buildings in north Bedfordshire where the collection is kept. You'd be very welcome to visit anyway by arrangement, taking pot...

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