What I find puzzling, as well as all the other things, is why it completely ignores the Neutral lead.
Unwell Fluke 1652
- Thread starter JohnW2
- Start date
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Indeed. Given what Rocky reminded us yesterday, might it be conceivably in some way (goodness knows what!) related to the fact that the Neutral lead doesn't have a fuse (but the other two, whose presence it insists upon, do)??
Kind Regards, John
It would be unnecessary (and crazy) for them to use a high voltage to test the fuse. As for the other things you mention, I suppose it's not impossible - it really depends on how they do the fuse test.
Kind Regards, John
John if theres anything you think may crack this, let me know on here what it is and I will ask one of our main suppliers to speak to someone with a bit of clout at Fluke for you.
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Many thanks. I'll do some thinking.
I suppose one obvious question is whether there is a way (involving 'tampering with the hardware', if necessary!) of disabling the "leads present" test - since I strongly suspect that my old machine would still work fine if it didn't do the test. However, I fear that that could probably only been done in the firmware, and it's unlikley that I would be able to do that (unless someone can instruct me otherwise!).
Kind Regards, John
I've been continuing to scrape the barrel of thoughts about this.
In addition to the one difference between N and L/PE I've already mentioned (only the latter two are fused), the only other thing that has come to mind is that only L and PE are involved in resistance measurements (IR or 'continuity'). I suppose that might also be the reason why (just) those two are fused, since I doubt that, even if one did 'silly things', one could get excessive currents flowing in leads with any of the other functions (voltage, loop resistance and RCD tests).
Kind Regards, John
Maybe we're looking at this the wrong way round.
As we're supposed to switch on with leads out, so that it can do the fuse test, perhaps the 'LEAd' display is not telling us that the leads are out, but telling us that we may now put them in.
I still cannot see why the neutral is not fused, if the PE needs to be.
As we're supposed to switch on with leads out, so that it can do the fuse test, perhaps the 'LEAd' display is not telling us that the leads are out, but telling us that we may now put them in.
I still cannot see why the neutral is not fused, if the PE needs to be.
As discussed, the instructions do not say that one should/must switch the machine on with leads out - there is merely an explanation hidden away towards the end of the manual which indicates that the fuse test will (for some reason which we don't understand) be skipped if it is switched on with the leads in! If they were really advising (or insisting) that the machine should always be switched on without leads, they would surely state that somewhere 'up front' in the manual??
Hmmm. I'm not sure that would explain why "LEAd" re-appears if one unplugs the L and/or PE lead whilst the machine is switched on.
As I recently wrote, maybe it is felt/believed that there is only a risk of excessive current in leads during resistance measurement (IR or 'continuity') - and the N lead is not involved in those measurements. Furthermore, since any excessive current would have to flow through two leads, it is only really necessary to fuse two of the three (i.e. if there were an excessive current in N, there would also have to be in L and/or PE).
Kind Regards, John
To tell you to put it back.
Quite - so we're back to square one, with that message merely pointing out that a lead is unplugged!To tell you to put it back.
Kind Regards, John
Yes, but a slight difference between:
You forgot to plug in the leads, and
Fuse test complete, you may plug in the leads now.
You forgot to plug in the leads, and
Fuse test complete, you may plug in the leads now.
Yes, but I was talking about a third one - "Although the fuse test was undertaken when you switched me on, you now seem to have pulled out a lead" !
Kind Regards, John
Another possibility - although I agree no more likely than any other explanation (inc "because we can").
Could the split plugs have a function in allowing a test/calibration rig to access the unit's circuits in non-standard ways ?
Could the split plugs have a function in allowing a test/calibration rig to access the unit's circuits in non-standard ways ?
Yes, I considered that, and it certainly could explain the use of split sockets (albeit only with L and PE *). However, even if there were such a reason for having split sockets, it would not explain why the 'leads present' test is done, or why the machine seemingly refuses to function (**) if it thinks that test has been 'failed'.
* I suppose for convenience (fewer different components to source/stock), all three lead sockets are 'split'. However, the two halves of the N one are connected by a fat PCB track.
** Watch this space - I may soon have something more to report!
Kind Regards, John
I think I have probably been wrong in saying (throughout) that the appearance of the "LEAd" message, per se, inevitably means that the machine 'will not function' (at all) ....
If the PE lead is (genuinely) not plugged in, then there are very few tests that could actually be done - IR, 'continuity', L-PE loop impedance and the RCD tests all use/require that lead. So, in theory, just about (** - see below) the only test which can be done with the PE lead (genuinely) missing is the L-N loop impedance. Similarly, if the L lead is (genuinely) not plugged in, then there are essentially (** - see below) NO tests that can be done.
If I switch on a (working!) 1652 with just the PE lead missing, I can, despite "LEAd" showing in the display, undertake a L-N loop impedance measurement, simply by selecting that function and pressing the 'Test' button. It can't do any other tests, but that's primarily because they all require a PE lead to be connected to something. It therefore seems that absence of a lead (and appearance of "LEAd") does not, per se, stop the machine working. EFLI ... can you confirm that is true of your machine?
** In theory, one should be able to undertake some voltage measurements with the L or PE lead (just one of them) missing - N-PE voltage and L-N voltage respectively. However, unless I've been very unlucky in acquiring two 1652s with the same 'fault', it seems that the only voltage one can measure is L-PE. The manual indicates that one can use the F1 button to toggle to L-N or N-PE, but that has never worked with either of my machines (although the F1 button has 'worked as expected' with respect to all other types of measurement). EFLI ... is that also true of your machine?
More soon!
Kind Regards, John
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