Current Probes

I've been trying to incorporate amperage into my troubleshooting technique. I own an amp clamp, but have never really been able to use it for anything other than relative compression waveforms. I've tried to current ramp fuel pumps with it and the Vantage, have only managed to get miniscule waveforms with little detail.
It's the Innova 3447
The settings are: 1mv=1A & 10mv=1A
I tested its accuracy against the amp meter in my Vantage MT2400.
A GM vent solenoid draws about 0.56A (560ma) according to the series ammeter.
The same solenoid on the 200mv scale, with the probe set to 10mv=1A shows 4.6mv. That's fairly close to the actual .5A measures in the first place. So, so far so good.
It is very hard to zero at those scales with the thumb wheel however. The converted voltage is so close to the floating "ghost voltage" on the display, I can see how it would be easy to blow a call in a real diagnosis instead of just making a mess and playing around on the wife's kitchen table!
One of the things I would like to do is current waveforms of fuel pumps and other electric motors.
So I grabbed an old power vent window motor I saved for my Lincoln, and measured it's current draw first in series. (FYI: with the motor on my kitchen table free spinning). It reads between 0.150A-0.180A (150ma to 180ma).
Again, on the DMM with the amp probe, we were close enough for government work. About 1.5mv. Again, zeroing the tool at these scales is difficult, and nearly impossible on graphing mode.
On to the Verus! Waveforms are more than disappointing...
Maybe I'm just expecting too much for such little current?
All hash, even with the filter on. I tried the 20amps auto setting, and tried adjusting the scales manually in the voltage probe settings. Nothing produced any sort of useable waveform.
I think I'm just using the wrong tool for the job. I've been looking at the AES wave generic low current probe available in the tools section.
Current probe, ScannerDanner Tools
settings are 1mv=100ma (10mv=1A. The same as the Innova)
and 1mv=10ma (100mv=1A). That's the setting I think I should be using for electric motor current waveforms.
Does anyone have any experience with this current probe? Is there anything I'm missing or doing fundamentally wrong?
Any and all input is appreciated, as always!
Thanks,
Noah

Noah wrote: It's the Innova 3447

Hah! Even before I followed the link, I KNEW which probe you were referring to, 'cause I've been eyeing the same one!

I like the idea of this one, since it's range 0-600A and theoretically could do the job of a low AND high range current probe. Then again, I almost never need to measure over 300A...

Does anyone have any experience with this current probe? Is there anything I'm missing or doing fundamentally wrong?

Not with that specific one, but the Snap-On low range probe is very similar. I find that these types of probes have a very hard time accurately measuring below 500mA, and get especially noisy below 250mA. When doing parasitic draw testing, for example, I've found that I can change the reading simply by removing the probe, rezeroing, and remeasuring. Unless it's a big draw, I never get the same value twice

On to the Verus! Waveforms are more than disappointing...
Maybe I'm just expecting too much for such little current?
All hash, even with the filter on. I tried the 20amps auto setting, and tried adjusting the scales manually in the voltage probe settings. Nothing produced any sort of useable waveform.

Yeah, too low a draw for the probe, and I'm sure that motor was freewheeling like crazy! Not sure how you'd load it, exactly, but I'm positive the waveform quality would improve.

So I guess I was working against myself. Having the scope plugged in and charging was making a ton of noise in the pattern :blush:
Which of course was very noticeable at 100 or 200mv scale.
I still think the AES wave probe with the 1mv=10ma (100mv=1A) scale would give more definition, but the innova seems plenty capable of making reasonably accurate measurements.

Idk how I missed your reply Tyler, thanks for getting back to me.

That's kind of why I got the innova, I figured it would be best of both worlds. I've had plenty of success with starter current waveforms, but lesser success on fuel pumps and lower current motors. It works, don't get me wrong, but I think I could get more definition with a dedicated low current probe.

And yeah, the quarter window motor was humming right along! I tried putting a load on it, but it just wanted to eat the table cloth! :whistle:

Hey Noah. I have the same probe as the AES generic one, the PDI version. I believe PDI is the manufacturer (I could be wrong). Anyways, I can run whatever tests you want with the current probe before you spend the money, so you know it does what you need it to do. Just let me know. Just keep in mind that I only have a Modis and I'd have to take pics of the waveforms and upload them here so the quality of the pics may not be great. HTH.

*shaka*

I had similar issues with a innova and fluke amp clamp but then i tried a cheap intellisens i2 current probe and it performed much better then my expectations. Hassle free and cheap probe can measure up to 100A. You can check it HERE .

The Hantek low curent clamp has been 100% successful with me for injectors, coils, fans and fuel pumps, I have never tried it for anything below 50ma as I bought a budget price low range clamp meter for parrasitic drains. Hantek quality is a bit of a gamble my Hantek high range clamp wa dead on arrival, I had to open it up and repair the range switch before I could use it.

Andy.MacFadyen wrote: The Hantek low curent clamp has been 100% successful with me for injectors, coils, fans and fuel pumps, I have never tried it for anything below 50ma

• as I bought a budget price low range clamp meter for parrasitic drains

. Hantek quality is a bit of a gamble my Hantek high range clamp wa dead on arrival, I had to open it up and repair the range switch before I could use it.

Which low rang amp clamp? Got a link?

bruce.oliver wrote:

Andy.MacFadyen wrote: The Hantek low curent clamp has been 100% successful with me for injectors, coils, fans and fuel pumps, I have never tried it for anything below 50ma

• as I bought a budget price low range clamp meter for parrasitic drains

. Hantek quality is a bit of a gamble my Hantek high range clamp wa dead on arrival, I had to open it up and repair the range switch before I could use it.

Which low rang amp clamp? Got a link?

A fairly inexpensive CEM DT337 Clamp meter works a treat , info in this thread thread link

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Looks like this one from Aeswave for $130
Esi-687

But they recommend this one for parasitic drains. $200
Esi-688

I'm going to have to do some testing. I have a SO low current probe and an aeswave low current probe. I'll use those and put my meter in series and see how close the current probes are to the internal amps of my meter

bruce.oliver wrote: But they recommend this one for parasitic drains. $200
Esi-688

The main difference is the size of the jaws you would need the larger jaws for large diesels.

Hooked to the main battery earth the smaller one I have can easily show if my mobile phone charger is plugged in and if it has a phone charging.
I reckon that for chasing parasitic drains you need to able to read with repeatable good accuracy in the 10 to 20ma range and the model I have will do that.

Here is what looks like that $200 one for $100 on eBay.
Cem DT-338

Andy.MacFadyen wrote:

bruce.oliver wrote: But they recommend this one for parasitic drains. $200
Esi-688

The main difference is the size of the jaws you would need the larger jaws for large diesels.

Hooked to the main battery earth the smaller one I have can easily show if my mobile phone charger is plugged in and if it has a phone charging.
I reckon that for chasing parasitic drains you need to able to read with repeatable good accuracy in the 10 to 20ma range and the model I have will do that.

Aeswave also says the one with the bigger jaws has better zero stability.

I wonder if the CEM meters are the same as the ESI just rebranded. Or are they knockoffs

bruce.oliver wrote: I'm going to have to do some testing. I have a SO low current probe and an aeswave low current probe. I'll use those and put my meter in series and see how close the current probes are to the internal amps of my meter

Definitely interested to see the results.

Just did a quick test today, we were busy. Test light in series with my meter and an adjustable resistor. Meter read 156 milliamps. Aeswave current probe showed about 165 milliamps. Adjusted the resistor in several stages all the way down to 5 milliamps. The current probe was consistent at 8-10 milliamps higher than the meter on internal amps. At 5 milliamps the current probe showed about 15 milliamps. I did have to rezero the current probe several times in the process.

I will check it on a car but it might be the weekend before I get a chance. And I will throw the snapon current probe into the mix to

bruce.oliver wrote: Just did a quick test today, we were busy. Test light in series with my meter and an adjustable resistor. Meter read 156 milliamps. Aeswave current probe showed about 165 milliamps. Adjusted the resistor in several stages all the way down to 5 milliamps. The current probe was consistent at 8-10 milliamps higher than the meter on internal amps. At 5 milliamps the current probe showed about 15 milliamps. I did have to rezero the current probe several times in the process.

I will check it on a car but it might be the weekend before I get a chance. And I will throw the snapon current probe into the mix to

Well, that's a lot better than the last time I tried to use my low amp probe! :lol: But still not exact, eh? Would you consider this as a replacement for a DMM?

I think so, but there are more experienced and smarter people on here than me. Hopefully they will chime in.

I use mine all the time for parasitic drains. I'll post up after I do some more testing.