On Fri, 9 Feb 2018 12:00:13 -0800 (PST), wrote:

On Friday, 9 February 2018 15:08:52 UTC, Archibald Tarquin Blenkinsopp wrote:
On Fri, 9 Feb 2018 02:07:44 -0800 (PST), tabbypurr wrote:
On Friday, 9 February 2018 00:15:50 UTC, Archibald Tarquin Blenkinsopp wrote:
On Thu, 8 Feb 2018 15:47:24 -0800 (PST), tabbypurr wrote:
On Thursday, 8 February 2018 20:04:31 UTC, Archibald Tarquin Blenkinsopp wrote:
On Thu, 8 Feb 2018 11:51:21 -0800 (PST), tabbypurr wrote:

I expect the design was fine when approved by their buyer, but you know how chinese manufacturers cut corners afterwards. The excessive noise level leads me to think it wasn't just a fault. And if it had been a motor fault, a mains lead going from cold to hot would mean the motor windings going from hot to meltdown fairly quickly. I did have a quick look at the motor, it showed no sign of overheating.

And they evidently became aware of the problem, so it wasn't a 1 off, as their following replacement model was unusually quiet.

Less than 3A, even at 1 Ohm the cable shouldn't dissapate a noticable
amount of power.

good flex no, but CCS would

Not come across the term for mains cable before. Copper Clad Steel?

yup

As far as I'm aware it's never used for flex if thats what you mean.
It would be totally unsuitable. At 50 Hz the steel would be passing
the current, the copper would be of little use apart from corrosion
protection.

it gets used sometimes in corner cutting noncompliant chinese goods. needless to say its current rating is much lower than copper.

It,s used for RF amongst other things, where the current rating is of
no significance and only for fixed installations. No vaccum cleaner
would be fitted with such a component.

So you don't buy goods from China. We do. It gets used on occasion. It gets rejected.

It probably would have had a 13A fuse, but if it did have a shorted
turn I would expect the aroma to be quite strong.

From memory, I'm fairly sure there was obvious damage to the
commutator/ brushes in these cases.

it wasn't that, the thing ran fine. It's easy to see when there's a turn shorted.

If the mains cable was overheating it wasn't running fine.
Paradoxically, it may have an open circuit. This wasn't a common
problem though, and on the only time it happened to me, I never
thought of measuring the current.

I see you're being stupid again. I used it, I examined it, I checked out the motor. It was running correctly, there was no motor problem. If you can't get your head round the simple stuff you'll go back in the filter.

I can get my head around simple stuff. You state that the motor was
noisy. The cable will not cause this. Noise is due to bearing
problems, electrical problems with the rotor or even just a good old
mechanical impediment.

with respect I said the vac was noisy, not the motor. The motor was not noisy. The nature of the noise was plainly not due to bearing problems or rotor problems.

Noise is vibration, which is the rapid accelleration and decelleration
of a mechanical item, a signifcant level of force is needed to produce
noise and a high resistance cable will not contribute to that force.

the item producing the noise was air. That's where the noise came from, badly designed airflow paths.

Work = force x distance so your unwanted vibration is going to require
more power, hence the heating effect in the cable.

Please please dont filter me, I dont know what I'd do if I couldn't
communicate with thick plonkers.

You have not examined the goods, don't know the facts, don't know the cause of the problems, have made wrong guesses and think you know it all, and that I who does have the facts doesn't. I'm pretty sure I know who's the fool. Again.


Ah but you fail to grasp the relavance of what you report. Noise does
not appear as if by magic, without a source, without reason.

Turbulent airflow costs a lot in terms of energy believe me. Since
November I have been involved with little else, and although you
cannot see a way to connect noise and current, anyone with a small
amount of experience would find no problem in identification of the
fault. On the face of it the airflow in a vaccum would not seem to
have a relationship to an overcurrent event, but the excess current
has to go somewhere, the little electrons dont get lost inside the
dusbag you know :-)

Manufactured items can be doddle, simply because the thing worked
once, or an identical unit can be used to help identify the fault.

I spend a lot of time on the phone to people trying to sort out
problems. I use the calls to get figures, measurements, what the
results are, not what they think the problem is.

More often than not they were unable to record the relevant details or
failed to see the patently obvious.

The result being a trek around the UK to unblock a filter or change a
fuse.

One does not guess at anything. It isn't professional.

I certainly dont know it all incidentally, I have a sneaking suspicion
that I never will either :-)

Onward & upward

AB

I thought you were killfiling me?