Paul Borian on fri 22 feb 08
when dealing with electrical issues around the studio and with my van
there are times when i need an amp meter - the meter i have is just a
stanadard multimeter that measures volts and ohms. I always thought the
amp meter were really expensive because some contractors i have dealt with
that use them said they paid a lot for them. But i was at Lowes the other
day and they had several of them that did not seem too spendy. They had a
few made by Greenlee, a major producer of electrical equipment, that were
just like the mulitmeters i have but they could also measure amps. Then
they had another one, for like $75, that was specifically for amps, and
that is probably the one i would get. But the relatively low price makes
me wonder how useful it really is. Can you really get something good for
that price?
i would be interested to hear if anyone has a good meter and what they
paid for it. Mostly i need to measure the amps my electric kilns draw when
working on them and sometimes the cranking amps the batteries on my van
and also a truck i just bought (ford 7.3 diesel) - the batteries are
supposed to be good for 1000 cold cranking amps but they seem kind of low,
and it would be really convenient to put a meter on them when cranking to
see they are putting out.
any info appreciated.
thanks,
Paul
Fredrick Paget on sat 23 feb 08
>
>i would be interested to hear if anyone has a good meter and what they
>paid for it. Mostly i need to measure the amps my electric kilns draw when
>working on them and sometimes the cranking amps the batteries on my van
>and also a truck i just bought (ford 7.3 diesel) - the batteries are
>supposed to be good for 1000 cold cranking amps but they seem kind of low,
>and it would be really convenient to put a meter on them when cranking to
>see they are putting out.
>any info appreciated.
>thanks,
>Paul
Paul I am afraid you will have to buy two meters to measure those two
things. They are in a different category entirely.One is AC and the
other is DC. I doubt a useful meter can be found that will work for
both.
For the kiln you need a tong meter as it is the most handy for AC
loads like a kiln. you just clamp the tong around one of the wires
(not both at once) and it gives a pretty acurate AC amp reading.
For the battery check Harbor Freight for a special purpose tester for
battery current which is DC by the way.
A real DC ammeter that can measure 1000 amps or more would use a
shunt in the cirduit. It is a heavy gauge resistance of very low ohms
value and at full rated current a 50 millivolt drop appears across
it and is measured with a dc millivoltmeter hooked to the shunt. A
decent multimeter can do that.
--
Fred Paget
Twin Dragon Studio
Mill Valley, CA, USA
fredrick@well.com
Charter Member Potters Council
Kenneth on sat 23 feb 08
Paul,
You need a meter that will measure AC amperage for measuring the
current draw on your electric kiln=2E To determine what meter will
meet that need, check the amperage rating on your kiln and the
voltage (probably 240V a/c in USA)=2E If you also want to be able to
check the current draw on your auto battery (or any other battery)
you will need to look for a meter that also measures DC amperage=2E=20
This meter may be referred to as an ammeter or as a multimeter=2E Look
for a meter that has a "jaw" that clamps around the wire (one leg of
your power supply) on which you will be measuring the current draw=2E=20
Also, look for a meter that states somewhere on the case that it is
"Category III"=2E This is a safety rating that applies to electrical
testing devices and that would be best to ensure that you are
effectively insulated from the voltage and current while taking these
readings=2E There are meters out there that will measure the values
that you want, but lack this safety rating=2E Don't bother with them=2E=20=
Greenlee is a decent brand, as are Universal Electric, Meterman,
Fluke, Fieldpiece and others=2E Fluke would be one of the most
expensive=2E You should be able to get a meter that will cover these
values for $75 to $150 depending on other features you may choose to
buy=2E If you don't have much other use for an electrical meter, go
for the the basic features that meet your needs=2E The ranges on the
meter will need to be at least as high (preferably higher) than the
amperage rating on your kiln=2E For example, if your kiln is rated at
50A ac at 240V, then be sure to get a meter that states a range that
is 0-75A or higher=2E You will find that most meters have at least two
range option in each value that they measure, so maybe something like
0-200A ac and 0-400A ac; 0-100VAC, 0-400VAC; 0-1K ohms, 0-10K ohms,
etc=2E
The reason that the electrical contractor tells you that the meter he
is using is so expensive, is because it was! Professional
electricians need meters with many features an wide ranges, and very
durable for drops from ladders, etc=2E Their lives rely daily on the
safety and accuracy of their meter, sometimes measuring 480V ac or
higher, and hundreds of amps, so they invest in very high quality
meters=2E You should find something suitable at Lowes or Home Depot=2E
Good Luck,
Tracey Westfall
Pine Hill Pottery
tracey@pinehillpottery=2Ecom
larry on sat 23 feb 08
Hi, on the subject of amp meters, if you check at any good electronics stor=
e such as Fry's you should be able to find the meter you need. You will fin=
d the meters are multi function, including AC & DC along with OHMs. There i=
s little difference for the meter reading AC or DC. Best wishes. Larry=0D=
=0A=0D=0A----------------------------------------=0D=0AFrom: Fredrick Paget=
=0D=0ASent: Saturday, February 23, 2008 8:59 PM=0D=0ATo=
: CLAYART@LSV.CERAMICS.ORG=0D=0ASubject: Re: Need an amp meter - advice? =
=0D=0A=0D=0A>=0D=0A>i would be interested to hear if anyone has a good mete=
r and what they=0D=0A>paid for it. Mostly i need to measure the amps my ele=
ctric kilns draw when=0D=0A>working on them and sometimes the cranking amps=
the batteries on my van=0D=0A>and also a truck i just bought (ford 7.3 die=
sel) - the batteries are=0D=0A>supposed to be good for 1000 cold cranking a=
mps but they seem kind of low,=0D=0A>and it would be really convenient to p=
ut a meter on them when cranking to=0D=0A>see they are putting out.=0D=0A>a=
ny info appreciated.=0D=0A>thanks,=0D=0A>Paul=0D=0A=0D=0APaul I am afraid y=
ou will have to buy two meters to measure those two=0D=0Athings. They are i=
n a different category entirely.One is AC and the=0D=0Aother is DC. I doub=
t a useful meter can be found that will work for=0D=0Aboth.=0D=0AFor the ki=
ln you need a tong meter as it is the most handy for AC=0D=0Aloads like a k=
iln. you just clamp the tong around one of the wires=0D=0A(not both at once=
) and it gives a pretty acurate AC amp reading.=0D=0A=0D=0AFor the battery =
check Harbor Freight for a special purpose tester for=0D=0Abattery current =
which is DC by the way.=0D=0A=0D=0AA real DC ammeter that can measure 1000 =
amps or more would use a=0D=0Ashunt in the cirduit. It is a heavy gauge res=
istance of very low ohms=0D=0Avalue and at full rated current a 50 millivo=
lt drop appears across=0D=0Ait and is measured with a dc millivoltmeter hoo=
ked to the shunt. A=0D=0Adecent multimeter can do that.=0D=0A=0D=0A--=0D=0A=
Fred Paget=0D=0A Twin Dragon=
Studio=0D=0A Mill Valley, CA, USA=0D=0A =
fredrick@well.com=0D=0A=0D=0A Charter Member Potters Co=
uncil=0D=0A=0D=0A__________________________________________________________=
____________________=0D=0AClayart members may send postings to: clayart@l=
sv.ceramics.org=0D=0A=0D=0AYou may look at the archives for the list, post =
messages, change your=0D=0Asubscription settings or unsubscribe/leave the l=
ist here: http://www.acers.org/cic/clayart/=0D=0A=0D=0AModerator of the li=
st is Mel Jacobson who may be reached at melpots2@visi.com=0D=0A=0D=0A
JQPublic on sun 24 feb 08
Fred, your information is incorrect. See below
Paul:
Go buy an AMPROBE RS-1. They are about $80 and available at any better
electrical supply house.
They look like a giant black lobster claw that opens and you stick the wire
of whichever circuit you are measuring into.
It works by conductance, I'm told. There are also ports on the thing into
which you can stick probes and use it like a volt/ohm meter.
Go here for more information:
http://www.electricsuppliesonline.com/amrsroscclmu.html
There are other models for varying uses, but for checking a regular electric
kiln, this is the one that will do most everything for you.
Later,
JQP
----- Original Message -----
From: "Fredrick Paget"
To:
Sent: Saturday, February 23, 2008 10:38 PM
Subject: Re: Need an amp meter - advice?
> Paul I am afraid you will have to buy two meters to measure those two
> things. They are in a different category entirely.One is AC and the
> other is DC. I doubt a useful meter can be found that will work for
> both.
> For the kiln you need a tong meter as it is the most handy for AC
> loads like a kiln. you just clamp the tong around one of the wires
> (not both at once) and it gives a pretty acurate AC amp reading.
>
> For the battery check Harbor Freight for a special purpose tester for
> battery current which is DC by the way.
>
> A real DC ammeter that can measure 1000 amps or more would use a
> shunt in the cirduit. It is a heavy gauge resistance of very low ohms
> value and at full rated current a 50 millivolt drop appears across
> it and is measured with a dc millivoltmeter hooked to the shunt. A
> decent multimeter can do that.
----------------------------------------------------------------------
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Michael Wendt on sun 24 feb 08
Upon further investigation, I stand corrected.
Modern clamp on meters can measure DC
amperage by means of the Hall effect
wherein they measure the current by sensing
the strength of the magnetic field which varies
with respect to the amount of current flowing.
Those of you said so, way to go!
Regards
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Fredrick Paget on sun 24 feb 08
Well I can see where you are confused. I called it a tong meter and
you called it an Amprobe.
They are actually the same thing.
For a good explanation of how they work take a look at Wikipedia:
I note that there have been improvements and some of the new top of
the line ones will measure DC amperes which the older ones will not.
I must confess that since I have been retired from Electrical
Engineeringl for 25 years a few improvements have been made :'>
Fred Paget
>Fred, your information is incorrect. See below
>Paul:
>Go buy an AMPROBE RS-1. They are about $80 and available at any better
>electrical supply house.
>They look like a giant black lobster claw that opens and you stick the wire
>of whichever circuit you are measuring into.
>It works by conductance, I'm told. There are also ports on the thing into
>which you can stick probes and use it like a volt/ohm meter.
>
>Go here for more information:
>http://www.electricsuppliesonline.com/amrsroscclmu.html
>There are other models for varying uses, but for checking a regular electric
>kiln, this is the one that will do most everything for you.
>Later,
>JQP
>
>----- Original Message -----
>From: "Fredrick Paget"
>To:
>Sent: Saturday, February 23, 2008 10:38 PM
>Subject: Re: Need an amp meter - advice?
>> Paul I am afraid you will have to buy two meters to measure those two
>> things. They are in a different category entirely.One is AC and the
>> other is DC. I doubt a useful meter can be found that will work for
>> both.
>> For the kiln you need a tong meter as it is the most handy for AC
>> loads like a kiln. you just clamp the tong around one of the wires
>> (not both at once) and it gives a pretty acurate AC amp reading.
>>
>> For the battery check Harbor Freight for a special purpose tester for
>> battery current which is DC by the way.
>>
>> A real DC ammeter that can measure 1000 amps or more would use a
>> shunt in the cirduit. It is a heavy gauge resistance of very low ohms
>> value and at full rated current a 50 millivolt drop appears across
>> it and is measured with a dc millivoltmeter hooked to the shunt. A
>> decent multimeter can do that.
>
>----------------------------------------------------------------------
>Get a free email address with REAL anti-spam protection.
>http://www.bluebottle.com/tag/1
>
>______________________________________________________________________________
>Clayart members may send postings to: clayart@lsv.ceramics.org
>
>You may look at the archives for the list, post messages, change your
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>
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--
Twin Dragon Studio
Mill Valley, CA, USA
Michael Wendt on sun 24 feb 08
First, let me ask how JQP conforms to requirement
that his name be known? see next:
>Fred, your information is incorrect. See below
Paul:
Go buy an AMPROBE RS-1. They are about $80 and
available at any better
electrical supply house.
They look like a giant black lobster claw that opens
and you stick the wire
of whichever circuit you are measuring into.
It works by conductance, I'm told. There are also
ports on the thing into
which you can stick probes and use it like a volt/ohm
meter.
Go here for more information:
http://www.electricsuppliesonline.com/amrsroscclmu.html
There are other models for varying uses, but for
checking a regular electric
kiln, this is the one that will do most everything for
you.
Later,
>JQP
Second, I checked the source and the clamp
on meter only measures AC amps + or - 5%
AC clamp on meters work without being in
the circuit because the AC sine wave has an
inductive magnetic field that matches the AC
sine wave.
In contrast, DC current's magnetic field is constant
so the meter cannot measure it. It can only measure
a varying magnetic field caused by the passage
of current through a wire.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
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