I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

In article , Eric R Snow
wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS


Post this on Sci.Electronics Repair.

CAP

In article ,
Eric R Snow wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.

As long as the output is within what the scope can handle, I'd set to
1x, adjust the V/div as needed, and go. Yes, use the ground clip.

If the output from the genny is too high for the scope to handle
straight, you're going to need to "dump" some of it - Since I assume
you're wanting to do this to look at the waveform the genny is putting
out, you'll want a "pure resistance" load so that inductance doesn't
interact with/alter whatever ripple is present. A car headlight or three
wired in series would likely do the job quite nicely, dropping the
voltage without affecting the waveform.

Expect it to be a rather boring picture, though. You'll likely need to
dial the scale way up to see the ripple on an otherwise flat line when
looking at a generator output.

For an alternator, on the other hand, depending in spin speed/design
intents, it could be anything from dreadfully boring to rather
interesting to watch.

--
Don Bruder - - If your "From:" address isn't on my whitelist,
or the subject of the message doesn't contain the exact text "PopperAndShadow"
somewhere, any message sent to this address will go in the garbage without my
ever knowing it arrived. Sorry... http://www.sonic.net/~dakidd for more info

Agree with Don here. The output of the genny will be more meaningful
(realistic) if driving some of it's rated load. Just running open won't
tell you a lot. In any case use the 10x multiplier to range down into the
vertical amplifier.

Bob Swinney
"Don Bruder" wrote in message
...
In article ,
Eric R Snow wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.

As long as the output is within what the scope can handle, I'd set to
1x, adjust the V/div as needed, and go. Yes, use the ground clip.

If the output from the genny is too high for the scope to handle
straight, you're going to need to "dump" some of it - Since I assume
you're wanting to do this to look at the waveform the genny is putting
out, you'll want a "pure resistance" load so that inductance doesn't
interact with/alter whatever ripple is present. A car headlight or three
wired in series would likely do the job quite nicely, dropping the
voltage without affecting the waveform.

Expect it to be a rather boring picture, though. You'll likely need to
dial the scale way up to see the ripple on an otherwise flat line when
looking at a generator output.

For an alternator, on the other hand, depending in spin speed/design
intents, it could be anything from dreadfully boring to rather
interesting to watch.

--
Don Bruder - - If your "From:" address isn't on my
whitelist,
or the subject of the message doesn't contain the exact text
"PopperAndShadow"
somewhere, any message sent to this address will go in the garbage without
my
ever knowing it arrived. Sorry... http://www.sonic.net/~dakidd for more
info

According to Don Bruder :
In article ,
Eric R Snow wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.

As long as the output is within what the scope can handle, I'd set to
1x, adjust the V/div as needed, and go. Yes, use the ground clip.

In particular, if the voltage is less than perhaps 30V, for a
scope with 3 divisions above the center line and 3 below (with the
grounded line adjusted to zero), then a 1X setting on the probe, and 10
V/Div setting on the scope input should be fine.

If you adjust the grounded line to the bottom of the display, or
if your scope has a 20 V/Div range, then you can stay with the 1X
setting up to 60V. (If it is a bit higher, it won't hurt anything, you
will simply not be able to get the entire trace within the vertical
dimensions of the screen.

There are also 100X probes, for dealing with higher voltages,
and Tektronix once made a Freon filled one with a 1000X capability, for
*serious* high voltage.

As for the ground clip -- if the other side of the generator is
grounded, then you connect the ground clip to the generator ground. If,
however, the voltage is floating significantly above ground, you may
want to operate the scope in differential mode.

1) Use two probes on two inputs.

2) Both probes should be the same setting (1X or 10X)

3) Both probes should be the same speed, or differences in
reaction times between the two could distort the trace.

4) Both inputs should be the same (e.g. 20V/Div).

5) You need to switch the "invert" switch on for one of the
two channels only.

6) You need to switch the scope to "Add" mode (instead of
"Alt" or "Chop".

7) *Don't* connect the ground clips to anything. Remove them
from the probes so they don't hit anything above ground. (The
ground clips connect through to the ground pin on the power
plug, so you would be grounding the device through the scope,
probably burning up the wires on the probe.

At this point, you will be displaying the *difference* between
the two probes, so you can measure the voltage across something that is
well above ground. You will want the voltage capability of the probes
to be high enough to handle the voltage difference from ground. (I
think that 600V is typical for the 1X/10X switchable probes.)

I can't tell you exactly which switches to use, because I don't
have a 465 to see what they are labeled. My description was mostly
based on the 454 scopes, which I have used for many years, and
generically other Tek scopes use something somewhat similar.

If the output from the genny is too high for the scope to handle
straight, you're going to need to "dump" some of it - Since I assume
you're wanting to do this to look at the waveform the genny is putting
out, you'll want a "pure resistance" load so that inductance doesn't
interact with/alter whatever ripple is present. A car headlight or three
wired in series would likely do the job quite nicely, dropping the
voltage without affecting the waveform.

Expect it to be a rather boring picture, though. You'll likely need to
dial the scale way up to see the ripple on an otherwise flat line when
looking at a generator output.

For an alternator, on the other hand, depending in spin speed/design
intents, it could be anything from dreadfully boring to rather
interesting to watch.

Of course, there is the question of what he means by "generator"
in this case. It could be the DC power source from older cars used to
recharge the battery (as you are assuming). It could be an alternator
(as you have also suggested). It could be some form of audio or RF
signal generator (in which case typically the 1X range of the scope
probes is probably reasonable.

Or -- it could be some form of high voltage generator, in which
case none of the probe settings mentioned would be reasonable at all.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Eric -

I might have a manual on that for you.

What are you probing - one point referenced to ground ? if so ok.

However - be cautious - The scope ground - is the frame.

Most use a 2 to 3 prong adapter to isolate the ground lug from the power line.
Then use caution.

The x10 probe has a metal spring wire that changes scaling.

Is the generator ground earth ground or floating - if you floated your scope
then connect the scope lead to the ground lead as you say.
Otherwise - what would happen is the earth ground in the scope is connected
through the scope ground to the generator ground - and that might not be right.

send me an e-mail - I'll look in the shop to see what I have. Long time ago.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



Eric R Snow wrote:
I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

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If the signal you want to see is small to the DC voltage - use the AC coupled
switch on the input and look at only the AC waveform.

Martin
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



Don Bruder wrote:
In article ,
Eric R Snow wrote:


I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.


As long as the output is within what the scope can handle, I'd set to
1x, adjust the V/div as needed, and go. Yes, use the ground clip.

If the output from the genny is too high for the scope to handle
straight, you're going to need to "dump" some of it - Since I assume
you're wanting to do this to look at the waveform the genny is putting
out, you'll want a "pure resistance" load so that inductance doesn't
interact with/alter whatever ripple is present. A car headlight or three
wired in series would likely do the job quite nicely, dropping the
voltage without affecting the waveform.

Expect it to be a rather boring picture, though. You'll likely need to
dial the scale way up to see the ripple on an otherwise flat line when
looking at a generator output.

For an alternator, on the other hand, depending in spin speed/design
intents, it could be anything from dreadfully boring to rather
interesting to watch.


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On Thu, 09 Feb 2006 16:10:27 -0800, Eric R Snow
wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

What is the expected peak output voltage of these generators? Are
they AC, DC, or whut?

On Thu, 09 Feb 2006 21:31:55 -0600, "Martin H. Eastburn"
wrote:

Eric -

I might have a manual on that for you.

What are you probing - one point referenced to ground ? if so ok.

However - be cautious - The scope ground - is the frame.

Most use a 2 to 3 prong adapter to isolate the ground lug from the power line.
Then use caution.

The x10 probe has a metal spring wire that changes scaling.

Is the generator ground earth ground or floating - if you floated your scope
then connect the scope lead to the ground lead as you say.
Otherwise - what would happen is the earth ground in the scope is connected
through the scope ground to the generator ground - and that might not be right.

send me an e-mail - I'll look in the shop to see what I have. Long time ago.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



Eric R Snow wrote:
I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
Greetings Martin,
I wasn't exact enough when I asked my question. The generator is
actually an alternator. Just a typical one used when the power goes
out. It sits on rubber feet and so is isolated from the ground. I
guess that means it's floating. The scope will be plugged into the
mains while it's measuring the generator output. The voltage I can
measure with a DVM. But the wave form is what I want to look at. I
have ordered a manual for this 'scope and expect it soon. But if it
doesn't show, or is out of stock, I'll send you an e-mail.
Thanks,
Eric R Snow

On Thu, 09 Feb 2006 21:38:14 -0600, Don Foreman
wrote:

On Thu, 09 Feb 2006 16:10:27 -0800, Eric R Snow
wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

What is the expected peak output voltage of these generators? Are
they AC, DC, or whut?
Don,
AC. it's a small one. 850 watts. Good for little stuff but not quite
enough for the fridge.
Thanks,
Eric

On 10 Feb 2006 03:37:43 GMT, Ignoramus25009
wrote:

On Thu, 09 Feb 2006 16:10:27 -0800, Eric R Snow wrote:
I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

Sure, if the resulting voltage is within the scope's capabilities. I
have a operators and service manuals for your scope, free in electronic
form.

i
Thanks. If I need your electronic ones I'll let you know. I am
expecting a hard copy manual any day but it may be out of stock.
Eric

Ignoramus25009 wrote:
On Thu, 09 Feb 2006 16:10:27 -0800, Eric R Snow wrote:
I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

Sure, if the resulting voltage is within the scope's capabilities. I
have a operators and service manuals for your scope, free in electronic
form.

i

I wouldn't mind a copy as well. I have the same scope and pretty much
know how to use it, but manuals are never a bad thing to have around.

Thanks

JW

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

The safe way to do this is to make sure your generator is grounded
because the ground lead on your scope will be grounded and you
don't want current flowing in the ground lead or you will burn up
something or shock yourself. Unless you REALLY know what you are
doing you should not float the scope or alternator and obviously
you would not be asking how to do it here if that was the case.

Next is to use a 10x or 100x probe and connect it to the alternator
output. The probe choice will depend on the max input voltage of
your scope. Read the manual to make sure that you don't overvoltage
the input, lest you fry it. My guess is you will need a 100x probe.
Even then, you need to be careful that you do not exceed the max
rating of the probe. There are two little tiny resistors in there
that are used as a voltage divider. If you exceed the power dissapation
of the resistors, they burn out and your probe is now worthless.

This will allow you to check one leg. If you want to make leg to
leg measurements, you will need a two channel scope and two identical
probes. Put one probe on each leg and invert one channel and put the
scope in ADD mode. Now you can safely look at the combined voltage.

chuck

On 10 Feb 2006 11:35:35 -0800, "Dave" wrote:

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.
That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and
I know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps when I
ask a question.
ERS

On 10 Feb 2006 19:52:40 GMT, (Chuck
Sherwood) wrote:


The safe way to do this is to make sure your generator is grounded
because the ground lead on your scope will be grounded and you
don't want current flowing in the ground lead or you will burn up
something or shock yourself. Unless you REALLY know what you are
doing you should not float the scope or alternator and obviously
you would not be asking how to do it here if that was the case.

Next is to use a 10x or 100x probe and connect it to the alternator
output. The probe choice will depend on the max input voltage of
your scope. Read the manual to make sure that you don't overvoltage
the input, lest you fry it. My guess is you will need a 100x probe.
Even then, you need to be careful that you do not exceed the max
rating of the probe. There are two little tiny resistors in there
that are used as a voltage divider. If you exceed the power dissapation
of the resistors, they burn out and your probe is now worthless.

This will allow you to check one leg. If you want to make leg to
leg measurements, you will need a two channel scope and two identical
probes. Put one probe on each leg and invert one channel and put the
scope in ADD mode. Now you can safely look at the combined voltage.

chuck
All the generators I have seen are floating. If that's what is meant
by not being connected to ground. They only get grounded when
something is plugged into them and that something is grounded. As far
as the scope being grounded, it is grounded when it's plugged into the
AC mains. So if I use it to check the AC generator output it will be
grounded and the generator will not be. Unless it needs to be. If it
should be grounded to the scope ground then that's what I'll do. If I
can just touch the probe to one of the wires on the generator to
measure the frequency then that's what will get done.
ERS

On Fri, 10 Feb 2006 09:37:51 -0800, Eric R Snow
wrote:

On Thu, 09 Feb 2006 21:38:14 -0600, Don Foreman
wrote:

On Thu, 09 Feb 2006 16:10:27 -0800, Eric R Snow
wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

What is the expected peak output voltage of these generators? Are
they AC, DC, or whut?
Don,
AC. it's a small one. 850 watts. Good for little stuff but not quite
enough for the fridge.
Thanks,
Eric

OK. Yes, ground your scope to genny ground. The safest way to
operate might be to actually power the scope from the genny.

Set your probe on x10. Put it on channel 1. Set your trigger
controls on AC and norm, trigger mode (white button) on auto. Set
the little AC-gnd-DC switch under the channel 1 gain knob to gnd and
center the trace vertically on the screen. Set your horizontal sweep
at 2 mS/cm.

Now connect your probe to the hot wire. You should see about 1 cycle
of your AC waveform. You can now play with the various gain,
sweeprate and trigger settings to modify the display to see whatever
you want to see. Oh, I'd pull out the trig view button (near the Ch
1 gain knob) to set the scope at 20 MHz bandwidth.

On Fri, 10 Feb 2006 13:43:44 -0800, Eric R Snow
wrote:

On 10 Feb 2006 19:52:40 GMT, (Chuck
Sherwood) wrote:


The safe way to do this is to make sure your generator is grounded
because the ground lead on your scope will be grounded and you
don't want current flowing in the ground lead or you will burn up
something or shock yourself. Unless you REALLY know what you are
doing you should not float the scope or alternator and obviously
you would not be asking how to do it here if that was the case.

Next is to use a 10x or 100x probe and connect it to the alternator
output. The probe choice will depend on the max input voltage of
your scope. Read the manual to make sure that you don't overvoltage
the input, lest you fry it. My guess is you will need a 100x probe.
Even then, you need to be careful that you do not exceed the max
rating of the probe. There are two little tiny resistors in there
that are used as a voltage divider. If you exceed the power dissapation
of the resistors, they burn out and your probe is now worthless.

This will allow you to check one leg. If you want to make leg to
leg measurements, you will need a two channel scope and two identical
probes. Put one probe on each leg and invert one channel and put the
scope in ADD mode. Now you can safely look at the combined voltage.

chuck
All the generators I have seen are floating. If that's what is meant
by not being connected to ground. They only get grounded when
something is plugged into them and that something is grounded. As far
as the scope being grounded, it is grounded when it's plugged into the
AC mains. So if I use it to check the AC generator output it will be
grounded and the generator will not be. Unless it needs to be. If it
should be grounded to the scope ground then that's what I'll do. If I
can just touch the probe to one of the wires on the generator to
measure the frequency then that's what will get done.
ERS

I would either ground the genny to the outlet box that powers the
scope, or I'd just power the scope off the genny. If the genny is
floating you could have a common mode voltage that could cause
problems.

Another safe approach would be to drive a transformer with the genny
and observe the secondary with the scope. That'll reduce the voltage
and provide common-mode isolation. It'll also probably strip off any
high frequency content present on the genny wave, but there probably
isn't any there anyway.

Eric R Snow wrote:
"Dave" wrote:
Eric R Snow wrote:

[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and
I know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps
when I ask a question.

Well, consider http://groups.google.com when you have something totally
OT. Get out and meet new people.

On 10 Feb 2006 16:30:47 -0800, "Dave" wrote:

Eric R Snow wrote:
"Dave" wrote:
Eric R Snow wrote:

[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and
I know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps
when I ask a question.

Well, consider http://groups.google.com when you have something totally
OT. Get out and meet new people.

Does it bother you that I posted an electronics question on the
metalworking newsgroup? Don't you think that oscilloscopes could be
useful in a machine shop? And that others might also find the answers
to my question useful? I have used mine, with guidance from RCM, to
decipher encoder signals for digital readout of machine travel. And to
properly adjust, once again with directions, servo amps for a home
made cnc machine. Both of these examples are of interest to others on
this group. And the responses to my OT oscilloscope question leads me
to believe that other people on this newsgroup are interested in this
post also.
ERS

I found the manual in the shop - it is a tech full parts/design inside.
In the leather type covers tek used. If you get a xerox kind of junk -
let me know - and it is yours. Doesn't do me any good, my scope I bought new
from Tek and have the manual set. Phew!

Wish I had the B though - it was a good scope when I had it at work.
They dumped it - I kept the manual.

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



Eric R Snow wrote:
On Thu, 09 Feb 2006 21:31:55 -0600, "Martin H. Eastburn"
wrote:


Eric -

I might have a manual on that for you.

What are you probing - one point referenced to ground ? if so ok.

However - be cautious - The scope ground - is the frame.

Most use a 2 to 3 prong adapter to isolate the ground lug from the power line.
Then use caution.

The x10 probe has a metal spring wire that changes scaling.

Is the generator ground earth ground or floating - if you floated your scope
then connect the scope lead to the ground lead as you say.
Otherwise - what would happen is the earth ground in the scope is connected
through the scope ground to the generator ground - and that might not be right.

send me an e-mail - I'll look in the shop to see what I have. Long time ago.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder



Eric R Snow wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.
Thanks,
ERS

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Greetings Martin,
I wasn't exact enough when I asked my question. The generator is
actually an alternator. Just a typical one used when the power goes
out. It sits on rubber feet and so is isolated from the ground. I
guess that means it's floating. The scope will be plugged into the
mains while it's measuring the generator output. The voltage I can
measure with a DVM. But the wave form is what I want to look at. I
have ordered a manual for this 'scope and expect it soon. But if it
doesn't show, or is out of stock, I'll send you an e-mail.
Thanks,
Eric R Snow

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
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According to Eric R Snow :
On Thu, 09 Feb 2006 21:31:55 -0600, "Martin H. Eastburn"
wrote:

[ ... ]

Is the generator ground earth ground or floating - if you floated your scope
then connect the scope lead to the ground lead as you say.
Otherwise - what would happen is the earth ground in the scope is connected
through the scope ground to the generator ground - and that might not be right.

[ ... ]

I wasn't exact enough when I asked my question. The generator is
actually an alternator. Just a typical one used when the power goes
out. It sits on rubber feet and so is isolated from the ground. I
guess that means it's floating.

No bets. It depends on other interconnections. If it is
running from gasoline, and it is not connected to the house wiring at
all, then it is *probably* floating, at least until you touch some part
of the metal.

The scope will be plugged into the
mains while it's measuring the generator output. The voltage I can
measure with a DVM. But the wave form is what I want to look at.

You would probably be safer to use the differential measurement
setup which I described last night in another branch of this thread.
That way, you don't have to worry whether there is an accidental path to
ground from any part of it.

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 10 Feb 2006 11:35:35 -0800, "Dave" wrote:

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

Not all readers of RCM are one-trick ponies. Spehro is one
professional very competent in elex that contributes to this ng from
time to time.

Don Foreman wrote:
On 10 Feb 2006 11:35:35 -0800, "Dave" wrote:

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

Not all readers of RCM are one-trick ponies. Spehro is one
professional very competent in elex that contributes to this ng from
time to time.

Yes, but... as a reasonable newsgroup user... you will also find Sperho
over in the electronics groups. To ask an oscilloscope question in RCM
you should at least pretend it is connected to your Bridgeport's VFD.

Eric R Snow wrote:
"Dave" wrote:
Eric R Snow wrote:
"Dave" wrote:
Eric R Snow wrote:

[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and
I know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps
when I ask a question.

Well, consider http://groups.google.com when you have something totally
OT. Get out and meet new people.

Does it bother you that I posted an electronics question on the
metalworking newsgroup? Don't you think that oscilloscopes could be
useful in a machine shop? And that others might also find the answers
to my question useful? I have used mine, with guidance from RCM, to
decipher encoder signals for digital readout of machine travel. And to
properly adjust, once again with directions, servo amps for a home
made cnc machine. Both of these examples are of interest to others on
this group. And the responses to my OT oscilloscope question leads me
to believe that other people on this newsgroup are interested in this
post also.

Yes, if you were discussing what the oscilloscope could show you about
your generator I would not have an issue, but for oscilloscopes 101 or
a discussion of the Tektronix 465B calibration procedure I don't think
RCM is the best place. I own a 647A and a TDS 210 but I do not own a
465B. Until you are talking about both the generator and the scope I
think you would be simply be better off talking to another 465B owner
in an electronics newsgroup. Once the 465B is no longer the central
topic then please return to RCM and discuss what it has told you about
your generator.

On 11 Feb 2006 07:12:25 -0800, "Dave" wrote:

Eric R Snow wrote:
"Dave" wrote:
Eric R Snow wrote:
"Dave" wrote:
Eric R Snow wrote:

[...] Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and
I know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps
when I ask a question.

Well, consider http://groups.google.com when you have something totally
OT. Get out and meet new people.

Does it bother you that I posted an electronics question on the
metalworking newsgroup? Don't you think that oscilloscopes could be
useful in a machine shop? And that others might also find the answers
to my question useful? I have used mine, with guidance from RCM, to
decipher encoder signals for digital readout of machine travel. And to
properly adjust, once again with directions, servo amps for a home
made cnc machine. Both of these examples are of interest to others on
this group. And the responses to my OT oscilloscope question leads me
to believe that other people on this newsgroup are interested in this
post also.

Yes, if you were discussing what the oscilloscope could show you about
your generator I would not have an issue, but for oscilloscopes 101 or
a discussion of the Tektronix 465B calibration procedure I don't think
RCM is the best place. I own a 647A and a TDS 210 but I do not own a
465B. Until you are talking about both the generator and the scope I
think you would be simply be better off talking to another 465B owner
in an electronics newsgroup. Once the 465B is no longer the central
topic then please return to RCM and discuss what it has told you about
your generator.
Ohhhh Kkkkk.
ERS

A 10X probe will be fine for that 'scope.

Pete Stanaitis

P.S. Talk about Old scopes: I still have a 422 that works.
-------------------

Chuck Sherwood wrote:

The safe way to do this is to make sure your generator is grounded
because the ground lead on your scope will be grounded and you
don't want current flowing in the ground lead or you will burn up
something or shock yourself. Unless you REALLY know what you are
doing you should not float the scope or alternator and obviously
you would not be asking how to do it here if that was the case.

Next is to use a 10x or 100x probe and connect it to the alternator
output. The probe choice will depend on the max input voltage of
your scope. Read the manual to make sure that you don't overvoltage
the input, lest you fry it. My guess is you will need a 100x probe.
Even then, you need to be careful that you do not exceed the max
rating of the probe. There are two little tiny resistors in there
that are used as a voltage divider. If you exceed the power dissapation
of the resistors, they burn out and your probe is now worthless.

This will allow you to check one leg. If you want to make leg to
leg measurements, you will need a two channel scope and two identical
probes. Put one probe on each leg and invert one channel and put the
scope in ADD mode. Now you can safely look at the combined voltage.

chuck

On Thu, 09 Feb 2006 16:10:27 -0800, Eric R Snow wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do something
serious. Check the output of a couple generators. I have a 1X/10X probe.
Do I just set the 'scope to the right volts/div, the probe at 10x, and
touch the probe to the hot wire?

Yes, AFTER you set your vertical sensitivity to something sane.

Should the ground clip from the probe be
connected to the generator ground?

If the generator itself is floating, then yes. I wouldn't recommend using
the scope's ground clip for anything like line voltage - it's 60 (or 50)
Hz, so the inductance of the ground loop will be swamped out by whatever
you're measuring, and the scope's ground should provide a "good enough"
ground return to the mains to get a reasonable view of what your mains
looks like.

Or, as has been suggested, but isn't recommended, is to "float" the
scope, by using one of those 3-to-2 prong cheaters, and leave the ground
lead open - but then the whole scope case and everything sits at the
potential of whatever you clipped your ground clip to.

Now that I think about it, it'd be best to put your scope in differential
mode, and use two probes without ground clips - the scope will show you
whatever it sees between the probe tips, and neither one needs to be
grounded, in fact, _shouldn't_.

Hope This Helps!
Rich

On Sat, 11 Feb 2006 06:11:34 -0800, Dave wrote:

Don Foreman wrote:
On 10 Feb 2006 11:35:35 -0800, "Dave" wrote:

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the probe at
10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.

Not all readers of RCM are one-trick ponies. Spehro is one professional
very competent in elex that contributes to this ng from time to time.

Yes, but... as a reasonable newsgroup user... you will also find Sperho
over in the electronics groups. To ask an oscilloscope question in RCM you
should at least pretend it is connected to your Bridgeport's VFD.

And/or crosspost it. :-)

Cheers!
Rich

On Fri, 10 Feb 2006 12:02:26 -0800, Eric R Snow wrote:

On 10 Feb 2006 11:35:35 -0800, "Dave" wrote:

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the probe at
10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.
That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and I
know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps when I ask a
question.
ERS

Actually, your name sounds familiar to me, and I'm more of a regular on
sci.electronics.design/.basics, but also lurk rec.puzzles and
sci.engr.mech from time to time. :-)

Cheers!
Rich

On Sat, 11 Feb 2006 22:12:07 GMT, Rich Grise
wrote:

On Fri, 10 Feb 2006 12:02:26 -0800, Eric R Snow wrote:

On 10 Feb 2006 11:35:35 -0800, "Dave" wrote:

Eric R Snow wrote:
[...] Do I just set the 'scope to the right volts/div, the probe at
10x, and touch the probe to the hot wire? [...]

Yes, but before you electrocute yourself be sure to go over to a
sci.electronics group and post a lathe question.
That's an excellent suggestion! I know that I could post the 'scope
questions on sci.basics but the knowledge base here is pretty wide and I
know from the poster's names that their info is trustworthy. Also, I
answer questions here and am known here. This sometimes helps when I ask a
question.
ERS

Actually, your name sounds familiar to me, and I'm more of a regular on
sci.electronics.design/.basics, but also lurk rec.puzzles and
sci.engr.mech from time to time. :-)

Cheers!
Rich

Greetings Rich,
I do post on the basics group also. So I recognize your name and
advice. RCM has such a varied group of folks that there are lots of
good answers available. And since the knowledge base is so wide the
interests are also. Even though the name is METALWORKING many other
posts of interest to a large number of readers get posted here too. I
don't mind the off topic posts. If I don't wanna read 'em then I
don't. I do try to make sure any off topic posts I make are marked as
such so others can avoid reading them.
ERS

According to Don Bruder :
In article ,
Eric R Snow wrote:

I been havin' fun with my TEK 465B 'scope. But now I want to do
something serious. Check the output of a couple generators. I have a
1X/10X probe. Do I just set the 'scope to the right volts/div, the
probe at 10x, and touch the probe to the hot wire? Should the ground
clip from the probe be connected to the generator ground? I ordered
the manual but it hasn't arrived yet.

As long as the output is within what the scope can handle, I'd set to
1x, adjust the V/div as needed, and go. Yes, use the ground clip.

In particular, if the voltage is less than perhaps 30V, for a
scope with 3 divisions above the center line and 3 below (with the
grounded line adjusted to zero), then a 1X setting on the probe, and 10
V/Div setting on the scope input should be fine.

If you adjust the grounded line to the bottom of the display, or
if your scope has a 20 V/Div range, then you can stay with the 1X
setting up to 60V. (If it is a bit higher, it won't hurt anything, you
will simply not be able to get the entire trace within the vertical
dimensions of the screen.

There are also 100X probes, for dealing with higher voltages,
and Tektronix once made a Freon filled one with a 1000X capability, for
*serious* high voltage.

As for the ground clip -- if the other side of the generator is
grounded, then you connect the ground clip to the generator ground. If,
however, the voltage is floating significantly above ground, you may
want to operate the scope in differential mode.

1) Use two probes on two inputs.

2) Both probes should be the same setting (1X or 10X)

3) Both probes should be the same speed, or differences in
reaction times between the two could distort the trace.

4) Both inputs should be the same (e.g. 20V/Div).

5) You need to switch the "invert" switch on for one of the
two channels only.

6) You need to switch the scope to "Add" mode (instead of
"Alt" or "Chop".

7) *Don't* connect the ground clips to anything. Remove them
from the probes so they don't hit anything above ground. (The
ground clips connect through to the ground pin on the power
plug, so you would be grounding the device through the scope,
probably burning up the wires on the probe.

At this point, you will be displaying the *difference* between
the two probes, so you can measure the voltage across something that is
well above ground. You will want the voltage capability of the probes
to be high enough to handle the voltage difference from ground. (I
think that 600V is typical for the 1X/10X switchable probes.)

I can't tell you exactly which switches to use, because I don't
have a 465 to see what they are labeled. My description was mostly
based on the 454 scopes, which I have used for many years, and
generically other Tek scopes use something somewhat similar.

If the output from the genny is too high for the scope to handle
straight, you're going to need to "dump" some of it - Since I assume
you're wanting to do this to look at the waveform the genny is putting
out, you'll want a "pure resistance" load so that inductance doesn't
interact with/alter whatever ripple is present. A car headlight or three
wired in series would likely do the job quite nicely, dropping the
voltage without affecting the waveform.

Expect it to be a rather boring picture, though. You'll likely need to
dial the scale way up to see the ripple on an otherwise flat line when
looking at a generator output.

For an alternator, on the other hand, depending in spin speed/design
intents, it could be anything from dreadfully boring to rather
interesting to watch.

Of course, there is the question of what he means by "generator"
in this case. It could be the DC power source from older cars used to
recharge the battery (as you are assuming). It could be an alternator
(as you have also suggested). It could be some form of audio or RF
signal generator (in which case typically the 1X range of the scope
probes is probably reasonable.

Or -- it could be some form of high voltage generator, in which
case none of the probe settings mentioned would be reasonable at all.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article , ignoramus11720
@NOSPAM.11720.invalid says...

HP-333A-334A.pdf

Wavetek-148A.zip

I'd very much appreciate these two manuals.

Ned Simmons

In article , ignoramus21707
@NOSPAM.21707.invalid says...
On Tue, 14 Feb 2006 22:53:05 -0500, Ned Simmons wrote:
In article , ignoramus11720
@NOSPAM.11720.invalid says...

HP-333A-334A.pdf

Wavetek-148A.zip

I'd very much appreciate these two manuals.

Ned Simmons

http://igor.chudov.com/tmp/Tektronix...-333A-334A.pdf
http://igor.chudov.com/tmp/Tektronix...vetek-148A.zip

i


Thanks much.

Ned Simmons

On 15 Feb 2006 04:53:08 GMT, Ignoramus21707
wrote:

On Tue, 14 Feb 2006 22:53:05 -0500, Ned Simmons wrote:
In article , ignoramus11720
@NOSPAM.11720.invalid says...

HP-333A-334A.pdf

Wavetek-148A.zip

I'd very much appreciate these two manuals.

Ned Simmons

http://igor.chudov.com/tmp/Tektronix...-333A-334A.pdf
http://igor.chudov.com/tmp/Tektronix...vetek-148A.zip

i

Ig, do you have a manual for a Wavetek 144?