I need to remove the motor head of one of the central heating circulator pumps at home.

The pump is a WILO Star RS25/7

I have removed the two screws that attach the head to the body but the two parts are still firmly attached to each other.

I have put WD-40 and other similar sprays that are supposed to help with stuck parts.

I have used a flat bit screwdriver in between the two parts at the corners.

I have not tried light hammering or other more forceful measures for fear of damaging the pump or the piping around it.

What should I try?

For the other two, smaller, Wilo pumps in the house, after removing the two screws the head came out relatively easily.


Thanks,



Antonio

"asalcedo" wrote in message
...

I need to remove the motor head of one of the central heating circulator
pumps at home.

The pump is a WILO Star RS25/7

I have removed the two screws that attach the head to the body but the
two parts are still firmly attached to each other.

I have put WD-40 and other similar sprays that are supposed to help
with stuck parts.

I have used a flat bit screwdriver in between the two parts at the
corners.

I have not tried light hammering or other more forceful measures for
fear of damaging the pump or the piping around it.

What should I try?

For the other two, smaller, Wilo pumps in the house, after removing the
two screws the head came out relatively easily.

Make sure there are not 4 screws retaining the head.

Striking fairly hard with a rubber mallet or placing a piece of wood on it
and hitting with a hammer will usually dislodge a stubborn pump head.

In an earlier contribution to this discussion,
asalcedo wrote:

I need to remove the motor head of one of the central heating
circulator pumps at home.

The pump is a WILO Star RS25/7

I have removed the two screws that attach the head to the body but the
two parts are still firmly attached to each other.

I have put WD-40 and other similar sprays that are supposed to help
with stuck parts.

I have used a flat bit screwdriver in between the two parts at the
corners.

I have not tried light hammering or other more forceful measures for
fear of damaging the pump or the piping around it.

What should I try?

For the other two, smaller, Wilo pumps in the house, after removing
the two screws the head came out relatively easily.


Thanks,



Antonio

A gentle tap on the side with a soft mallet will probably do the trick.

Buy WHY do you want to remove it?
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Thanks for your replies.

I was able to remove it by using two large screwdrivers at the same time after gently tapping it.

I needed to remove it to do a powerflushing.

Regards,


Antonio

asalcedo
wibbled on Saturday 03 October 2009 14:41


I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

Are you using a true RMS meter? What happens if you measure it across a
load, eg a kettle? Are lights burning extremely bright? Are you fairly
confident that your meter is working correctly?[1]

The AC here is triphasic.

You mean 3 phase? If so, that's the same as the UK. One possibility is your
meter is reading it wrong if, for some reason, you are not getting a decent
sine wave (unlikely I would have . The other reason is your voltage is
genuinely dangerously high.

A couple of IC boards for motorized doors, permanently connected to the
mains, have recently failed. Perhaps it is related.

I will ask the electricity company as well

Phone them straight away on their emergency number. It's quite possible
there's a neutral fault which can give either a very high L-N voltage, or a
very low one depending on which of the 3 phases you are on.

Anyway, they ought to take your report seriously enough to send a bloke
round to check. As it could be an indicator of a serious network fault, I'd
expect them to turn up pretty quickly.

[1] The electricity company might ask you why you think your voltage is
high.

--
Tim Watts

This space intentionally left blank...

"Tim W" wrote in message
...
asalcedo
wibbled on Saturday 03 October 2009 14:41


I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

What do you mean "at the beginning"?
do you mean at the instant you connect the meter?
I would expect a DVM to stabilise almost immediately, and would regard the
reading as suspect. Can you try your meter on another supply, or try another
meter on yours? Is the battery in the meter good?

--
Graham.

%Profound_observation%

On Sat, 3 Oct 2009 23:01:07 +0100, "Graham." had this
to say:



"Tim W" wrote in message
...
asalcedo
wibbled on Saturday 03 October 2009 14:41


I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

What do you mean "at the beginning"?
do you mean at the instant you connect the meter?
I would expect a DVM to stabilise almost immediately, and would regard the
reading as suspect. Can you try your meter on another supply, or try another
meter on yours? Is the battery in the meter good?

I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

--
Frank Erskine

Frank Erskine wrote:
On Sat, 3 Oct 2009 23:01:07 +0100, "Graham." had this
to say:


"Tim W" wrote in message
...
asalcedo
wibbled on Saturday 03 October 2009 14:41

I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?
What do you mean "at the beginning"?
do you mean at the instant you connect the meter?
I would expect a DVM to stabilise almost immediately, and would regard the
reading as suspect. Can you try your meter on another supply, or try another
meter on yours? Is the battery in the meter good?

I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

I couldn't agree more.

Dave

In article ,
Frank Erskine wrote:
I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Hardly worth buying a traditional AVO if you already have a DVM. Just
measure across a load. Anything will do. Take the top off an appliance
plug or a lamp holder (both must be switched on and working) and measure
there.

But I'm not quite sure how you'd get a higher than actual mains voltage
with a high impedance meter? You can get strange readings on an circuit
that is switched off due to coupling of some sort - but not higher than
the mains voltage?

--
*Don't use no double negatives *

Dave Plowman London SW
To e-mail, change noise into sound.

On Sun, 04 Oct 2009 00:05:28 +0100, "Dave Plowman (News)"
had this to say:

In article ,
Frank Erskine wrote:
I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Hardly worth buying a traditional AVO if you already have a DVM.

Horses for courses, innit. I have two or three digital meters
(including a Fluke 73) (I can't find it at the moment!) and a couple
of analogue ones. I really prefer the analogue meters, although the
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

To check mains voltages of uncertain waveform/harmonic content it
would be better to contact a friend who does have an analogue (and
trusted) meter.

--
Frank Erskine

"Dave Plowman (News)" wrote in message
...
In article ,
rious Frank Erskine wrote:
I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Hardly worth buying a traditional AVO if you already have a DVM. Just
measure across a load. Anything will do. Take the top off an appliance
plug or a lamp holder (both must be switched on and working) and measure
there.

But I'm not quite sure how you'd get a higher than actual mains voltage
with a high impedance meter? You can get strange readings on an circuit
that is switched off due to coupling of some sort - but not higher than
the mains voltage?

Ferranti effect? (I'm not being totally serious).

--
Graham.

%Profound_observation%

On Sun, 04 Oct 2009 00:48:45 +0100, Graham. wrote:

"Dave Plowman (News)" wrote in message
...
In article ,
rious Frank Erskine wrote:
I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Hardly worth buying a traditional AVO if you already have a DVM. Just
measure across a load. Anything will do. Take the top off an appliance
plug or a lamp holder (both must be switched on and working) and
measure there.

But I'm not quite sure how you'd get a higher than actual mains voltage
with a high impedance meter? You can get strange readings on an circuit
that is switched off due to coupling of some sort - but not higher than
the mains voltage?

Ferranti effect? (I'm not being totally serious).

Ah, that's because it isn't in a Marconi cage! :-)



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

Graham. wrote:
"Tim W" wrote in message
...
asalcedo
wibbled on Saturday 03 October 2009 14:41

I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

What do you mean "at the beginning"?
do you mean at the instant you connect the meter?
I would expect a DVM to stabilise almost immediately, and would regard the
reading as suspect. Can you try your meter on another supply, or try another
meter on yours? Is the battery in the meter good?


i was similarly baffled measuring old car batteries
- it was a dud battery in the multimeter.

[g]

"Tim W" wrote in message
...
asalcedo
wibbled on Saturday 03 October 2009 14:41


I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

Are you using a true RMS meter? What happens if you measure it across a
load, eg a kettle?

How can you not measure the mains across a load? Ask everyone in the street
to turn everything off?

Bill

Frank Erskine wrote:
On Sun, 04 Oct 2009 00:05:28 +0100, "Dave Plowman (News)"
had this to say:

In article ,
Frank Erskine wrote:
I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.
Hardly worth buying a traditional AVO if you already have a DVM.

Horses for courses, innit. I have two or three digital meters
(including a Fluke 73) (I can't find it at the moment!) and a couple
of analogue ones. I really prefer the analogue meters, although the
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

To check mains voltages of uncertain waveform/harmonic content it
would be better to contact a friend who does have an analogue (and
trusted) meter.

Its been shown time and again that you can 'see' an analogue meter
faster than you can 'read' a digital one, as well.


A digital readout is inferior in every respect eccept precision. And
cost I suppose. Cheap as chips.;-)

In article ,
Frank Erskine wrote:
Hardly worth buying a traditional AVO if you already have a DVM.

Horses for courses, innit. I have two or three digital meters
(including a Fluke 73) (I can't find it at the moment!) and a couple
of analogue ones. I really prefer the analogue meters, although the
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings.

To check mains voltages of uncertain waveform/harmonic content it
would be better to contact a friend who does have an analogue (and
trusted) meter.

Or measure under load as I said. You can make up a dummy one for a DVM to
replicate a mechanical one if you wish.

--
*Nothing is foolproof to a sufficiently talented fool*

Dave Plowman London SW
To e-mail, change noise into sound.

On Sun, 04 Oct 2009 09:57:14 +0100, "Dave Plowman (News)"
had this to say:

In article ,
Frank Erskine wrote:
Hardly worth buying a traditional AVO if you already have a DVM.

Horses for courses, innit. I have two or three digital meters
(including a Fluke 73) (I can't find it at the moment!) and a couple
of analogue ones. I really prefer the analogue meters, although the
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings.

I use a digital meter (usually) for electronic work :-)

--
Frank Erskine

On Oct 4, 9:57*am, "Dave Plowman (News)" wrote:
In article ,
* *Frank Erskine wrote:

Hardly worth buying a traditional AVO if you already have a DVM.
Horses for courses, innit. *I have two or three digital meters
(including a Fluke 73) (I can't find it at the moment!) and a couple
of analogue ones. *I really prefer the analogue meters, although the
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings. * *


only on high impedance sources. I often preferred analogue for
electronics, and I did no shortage of electronics. Quicker readings,
much easier to work with when you need to watch what youre probing the
whole time (high voltages in awkward places, thanks to historic
designers), the fact that they can read well above fsd (by speed of
pointer movement), and digitals are a non-starter for non-steady
voltages.

The last generation of analogues had fet opamp input stages, same high
input impedance as digitals.


NT

In article
,
NT wrote:
You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings.


only on high impedance sources. I often preferred analogue for
electronics, and I did no shortage of electronics. Quicker readings,
much easier to work with when you need to watch what youre probing the
whole time (high voltages in awkward places, thanks to historic
designers), the fact that they can read well above fsd (by speed of
pointer movement), and digitals are a non-starter for non-steady
voltages.

Better DVMs have a second scale that sort of mirrors what a mechanical one
does. And have average max and minimum hold.

The last generation of analogues had fet opamp input stages, same high
input impedance as digitals.

I have a Heathkit valve voltmeter which does much the same. Long before
FETs were invented.

One beauty of a mechanical meter is it only needs batteries for resistance
measurement. Stick an FET on the front and you lose this.

--
*If PROGRESS is for advancement, what does that make CONGRESS mean?

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
Frank Erskine wrote:
Hardly worth buying a traditional AVO if you already have a DVM.

Horses for courses, innit. I have two or three digital meters
(including a Fluke 73) (I can't find it at the moment!) and a couple
of analogue ones. I really prefer the analogue meters, although the
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings.


Nor unless its working on very low current circuitry. On any case you
use a scope, not a DVM by and large.


To check mains voltages of uncertain waveform/harmonic content it
would be better to contact a friend who does have an analogue (and
trusted) meter.

Or measure under load as I said. You can make up a dummy one for a DVM to
replicate a mechanical one if you wish.


The load is the source impedance of the supply. Less than a few ohms
generally.

On Sun, 04 Oct 2009 00:40:33 +0100, Frank Erskine wrote:

Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

Urgh - the enfoced beeper drives me nuts on the lowest range. Handy to
have for continuity test, and a pain in the backside when tracing out lots
of low-resistance things. I keep meaning to take mine apart and add a
shut-off switch for the beeper...

JOOI, does anyone market a meter where the test leads *don't* have a
"tangle yourselfs up when nobody's looking" feature? :-)

In article ,
The Natural Philosopher wrote:
You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings.


Nor unless its working on very low current circuitry. On any case you
use a scope, not a DVM by and large.

A scope for measuring voltage? Ok for a quick guide, I suppose.


To check mains voltages of uncertain waveform/harmonic content it
would be better to contact a friend who does have an analogue (and
trusted) meter.

Or measure under load as I said. You can make up a dummy one for a DVM
to replicate a mechanical one if you wish.


The load is the source impedance of the supply. Less than a few ohms
generally.

A load is applied to a source in my world.

In yours it would make f all what type of meter is used.

--
*Time flies like an arrow. Fruit flies like a banana.*

Dave Plowman London SW
To e-mail, change noise into sound.

In message , Frank Erskine
writes

You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Having just had this annoyance and had to go and get the Avo why don't
DVMs just a "push to load" button that sticks 10k ohm or 100k ohm across
probes?

--
bof at bof dot me dot uk

In article om,
Jules wrote:
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

Urgh - the enfoced beeper drives me nuts on the lowest range. Handy to
have for continuity test, and a pain in the backside when tracing out
lots of low-resistance things. I keep meaning to take mine apart and add
a shut-off switch for the beeper...

On my 175 series you have to select the beep.

JOOI, does anyone market a meter where the test leads *don't* have a
"tangle yourselfs up when nobody's looking" feature? :-)

It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

--
*A backward poet writes inverse.*

Dave Plowman London SW
To e-mail, change noise into sound.

On Sun, 04 Oct 2009 18:03:17 +0100, Dave Plowman (News) wrote:
Urgh - the enfoced beeper drives me nuts on the lowest range. Handy to
have for continuity test, and a pain in the backside when tracing out
lots of low-resistance things. I keep meaning to take mine apart and add
a shut-off switch for the beeper...

On my 175 series you have to select the beep.

Git

It's permanently enabled on the lowest range on both of mine. Bah.

JOOI, does anyone market a meter where the test leads *don't* have a
"tangle yourselfs up when nobody's looking" feature? :-)

It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

Yeah, and I bust tips on leads with depressing regularity (usually doing
automotive stuff). I've found croc clips in cheapo stores which seem to
work well though, but decent leads with tips seem to be expensive.

The darn self-tangling feature drives me nuts :-)

cheers

Jules

On Sun, 4 Oct 2009 17:54:15 +0100, bof had
this to say:

In message , Frank Erskine
writes

You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Having just had this annoyance and had to go and get the Avo why don't
DVMs just a "push to load" button that sticks 10k ohm or 100k ohm across
probes?

At one time Avo used to make a meter specifically for 'electrical' as
opposed to 'electronic' work (ISTR that it was a variant of the Model
7, BICBW) - it was something like 500 ohms/volt, giving much more
sensible readings.
This meant that the movement could be much more rugged than usual as
well, so it could be dropped from the top of a stepladder (almost)
with little damage.

--
Frank Erskine

Dave Plowman (News) wrote:
In article ,
Frank Erskine wrote:
I certainly wouldn't use a digital meter for this type of measurement.
You'd be much better off using a traditional Avo or similar,
preferably with a fairly low ohms/volt characteristic, to try to avoid
silly readings due to induced voltages and the like.

Hardly worth buying a traditional AVO if you already have a DVM. Just
measure across a load. Anything will do. Take the top off an appliance
plug or a lamp holder (both must be switched on and working) and measure
there.

But I'm not quite sure how you'd get a higher than actual mains voltage
with a high impedance meter? You can get strange readings on an circuit
that is switched off due to coupling of some sort - but not higher than
the mains voltage?

From my point, I might be adding confusion by not expanding on what I
was measuring.

I had to avoid modern digital volt meters when I had to measure the
aircraft flap and slat asymmetry detector pot voltages. These are 3
phase and are fed at 110 volts, 400Hz. The object of the exercise was to
adjust the pots to the lowest voltage at a known point of flap and slat
travel, then reconnect them to the aircraft. They are there to freeze
the control surfaces so as to not allow one wing to be out of symmetry
with the one on the other side, by killing the drive mechanism stone dead.

What I found, was that due to the high input resistance, the meters
picked up residual voltages in other circuits, thus making the readings
over voltage. In this case, the asymmetry detection was quite happy to
see the same voltage from both sides, but the lift dump (spoilers for
landing) and the spoilers for flight worked in the opposite sense.

Another problem with some digital meters is that they provide a
resistance when trying to measure the current drawn by a circuit. The
current is dropped by the meters internal resistance. Because of this, I
use an old Avo Minor to measure current drawn, an almost as old Tandy
multimeter for general use, a not so old digi meter for continuity, cos
it has a tone output and a modern cheapo digi for anything else.

I hope you understand most of this.

Dave

Dave Plowman (News) wrote:
In article om,
Jules wrote:
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

Urgh - the enfoced beeper drives me nuts on the lowest range. Handy to
have for continuity test, and a pain in the backside when tracing out
lots of low-resistance things. I keep meaning to take mine apart and add
a shut-off switch for the beeper...

On my 175 series you have to select the beep.

JOOI, does anyone market a meter where the test leads *don't* have a
"tangle yourselfs up when nobody's looking" feature? :-)

It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

Many years ago, I made up lots of leads for my multi meters. They occupy
a 1/4 of a drawer :-)
Big crocks, small ones, probes that are thin and pointy, ones that are
fatter to take the current, ones that can be clipped onto the old style
TTL chips, live.

Has anyone seen clips that can be used on surface mount devices? Do they
exist? I don't mean those that clip onto all the pins at the same time.

Dave

In article . com,
Jules wrote:
It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

Yeah, and I bust tips on leads with depressing regularity (usually doing
automotive stuff). I've found croc clips in cheapo stores which seem to
work well though, but decent leads with tips seem to be expensive.

I've got a cheap meter for car stuff. The Fluke stays in the workshop.
To be perfectly honest a 20 quid one will be just about as accurate as the
Fluke. But won't have that lovely tactile feel to operate.

--
*Don't use no double negatives *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Dave wrote:
It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

Many years ago, I made up lots of leads for my multi meters. They occupy
a 1/4 of a drawer :-)
Big crocks, small ones, probes that are thin and pointy, ones that are
fatter to take the current, ones that can be clipped onto the old style
TTL chips, live.

The Fluke reacts to the wrong leads by giving inaccurate readings of very
low resistances - which is a pain if continuity checking.

Has anyone seen clips that can be used on surface mount devices? Do they
exist? I don't mean those that clip onto all the pins at the same time.

I try to stay well clear of surface mount. ;-) I'd guess RS would sell
them if anyone does.

--
*If all is not lost, where the hell is it?

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes
In article . com,
Jules wrote:
It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

Yeah, and I bust tips on leads with depressing regularity (usually doing
automotive stuff). I've found croc clips in cheapo stores which seem to
work well though, but decent leads with tips seem to be expensive.

I've got a cheap meter for car stuff. The Fluke stays in the workshop.
To be perfectly honest a 20 quid one will be just about as accurate as the
Fluke. But won't have that lovely tactile feel to operate.

One of my proudest moments is when I was working on the sales desk
(actually, I was the sales desk) at Fluke and someone phoned and asked
me why he should spend more than twice as much on a Fluke meter as on a
noname unit. I listened carefully to what he needed and advised him to
buy the cheap one.

My sales manager would have been livid if he found out but old man Fluke
would have given me a pat on the back.

A 20 quid DMM is highly unlikely to be as accurate as the Fluke but may
well be accurate enough.


--
Bernard Peek

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
You can't do much electronics stuff then - because the loading of an
mechanical meter gives false readings.


Nor unless its working on very low current circuitry. On any case you
use a scope, not a DVM by and large.

A scope for measuring voltage? Ok for a quick guide, I suppose.


To check mains voltages of uncertain waveform/harmonic content it
would be better to contact a friend who does have an analogue (and
trusted) meter.
Or measure under load as I said. You can make up a dummy one for a DVM
to replicate a mechanical one if you wish.


The load is the source impedance of the supply. Less than a few ohms
generally.

A load is applied to a source in my world.

In yours it would make f all what type of meter is used.


And there was me thinking you actually worked with electrons professionally.

In article ,
The Natural Philosopher wrote:
The load is the source impedance of the supply. Less than a few ohms
generally.

A load is applied to a source in my world.

In yours it would make f all what type of meter is used.


And there was me thinking you actually worked with electrons
professionally.

Then perhaps you'd explain how a high input impedance meter gives a
different reading from a low impedance one on mains - as per this thread?

--
*Toilet stolen from police station. Cops have nothing to go on.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sun, 04 Oct 2009 23:03:59 +0100, Dave Plowman (News) wrote:
Yeah, and I bust tips on leads with depressing regularity (usually doing
automotive stuff). I've found croc clips in cheapo stores which seem to
work well though, but decent leads with tips seem to be expensive.

I've got a cheap meter for car stuff. The Fluke stays in the workshop.

Well, once I get all my stuff shipped across the Pond I will have two, so
I suspect one will stay in the garage (neither are Flukes btw, sorry if I
gave that impression. My current US one is an Amprobe and it took me a
considerable amount of time to shop around for one that had exactly the
stuff that I wanted - but sadly non-tangling probes and a beeper disable
didn't appear in the feature list

cheers

Jules

On Mon, 05 Oct 2009 00:07:40 +0100, had this to say:

On 4 Oct,
Frank Erskine wrote:

At one time Avo used to make a meter specifically for 'electrical' as
opposed to 'electronic' work (ISTR that it was a variant of the Model
7, BICBW) - it was something like 500 ohms/volt, giving much more
sensible readings.

Model 40. Took 3ma FSD or 1.5ma with the button pressed for extra
sensitivity. A right PITA on anything electronic other than high power
stuff!

IIRC model 7 and 8 took 50ma FSD.

Microamps, shirley?

--
Frank Erskine

"Dave" wrote in message
...
Dave Plowman (News) wrote:
In article om,
Jules wrote:
Fluke is occasionally useful if just tapping out conductors because of
its continuity beeper :-)

Urgh - the enfoced beeper drives me nuts on the lowest range. Handy to
have for continuity test, and a pain in the backside when tracing out
lots of low-resistance things. I keep meaning to take mine apart and add
a shut-off switch for the beeper...

On my 175 series you have to select the beep.

JOOI, does anyone market a meter where the test leads *don't* have a
"tangle yourselfs up when nobody's looking" feature? :-)

It really annoyed me that such an expensive meter was supplied with PVC
rather than silicone leads. And that it came with only basic prods. And
they then have the nerve to charge about 40 quid for decent leads and
crock clips. Especially since much of their stuff is now made in China.

Many years ago, I made up lots of leads for my multi meters. They occupy a
1/4 of a drawer :-)
Big crocks, small ones, probes that are thin and pointy, ones that are
fatter to take the current, ones that can be clipped onto the old style
TTL chips, live.

Has anyone seen clips that can be used on surface mount devices? Do they
exist? I don't mean those that clip onto all the pins at the same time.


Yes they exist but they are fragile and eye-wateringly expensive.

On Sat, 3 Oct 2009 14:41:55 +0100, asalcedo wrote:

I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

If the volts really were up at 295v RMS you'd never be able to switch
an incandesent light on without it going flash, bang, dark and I
suspect there would be an awful lot of escaped magic smoke floating
about as well...

Your meter is lying for some reason.

--
Cheers
Dave.

In the end, as mentioned here, it was the 9V battery in the meter.

With a new battery, the reading is now 225V

The circuit boards that failed were due to moisture after heavy rain. When dry they came back to life. An improved sealing of the outdoors junction boxes where they are contained and some dielectric spray should prevent the problem from happening again.

Many thanks for your help.

Antonio

asalcedo
wibbled on Saturday 03 October 2009 14:41


I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

The AC here is triphasic.

A couple of IC boards for motorized doors, permanently connected to the
mains, have recently failed. Perhaps it is related.

I will ask the electricity company as well


Did you get to the bottom of this?

--
Tim Watts

This space intentionally left blank...

On Oct 3, 9:45*pm, Tim W wrote:
asalcedo
* wibbled on Saturday 03 October 2009 14:41



I have measured with a digital voltmeter the mains voltage at home in
Spain and got 295 V AC. At the beginning I get a reading of 240V and
then it quickly goes up until it stabilises at 295 V.

Is this reading correct?

Are you using a true RMS meter? What happens if you measure it across a
load, eg a kettle? Are lights burning extremely bright? Are you fairly
confident that your meter is working correctly?[1]

The AC here is triphasic.

You mean 3 phase? If so, that's the same as the UK.

Maybe not. In Norway they have three phases but no neutral. Each
house gets all three phases. In each room of the house the sockets
etc. are connected between one pair of phases. There is 240 Volts
between phases and therefore a lower voltage between any one phase and
earth.

THis had the amusing effect (when I lived there) that you could blow
one of the three fuses and then find that pluging in an electric
heater in one room made the lights work in the next room!

Robert



R