Anybody have and recommend this clamp-on DC Meter?

Surfpath

A.W. Sperry DSA500A 5-Function 9-Range 400-Ampere Digital Clamp Volt Meter
Attachment not found.

inetdog

Re: Anybody have and recommend this clamp-on DC Meter?

Surfpath wrote: »

A.W. Sperry DSA500A 5-Function 9-Range 400-Ampere Digital Clamp Volt Meter

According to the spec sheet, (http://www.tequipment.net/SperryDSA500A.html) this has both AC and DC voltage ranges, but the amp function is AC only. Not worth much for PV work.

SolaRevolution

Re: Anybody have and recommend this clamp-on DC Meter?

From the manual:

Response Time:
Approx. 2 seconds

This would drive me nuts.

icarus

Re: Anybody have and recommend this clamp-on DC Meter?

Buy the $60 sears model. Works very well, given the price.

Tony

Surfpath

Re: Anybody have and recommend this clamp-on DC Meter?

icarus wrote: »

Buy the $60 sears model. Works very well, given the price.

Tony

Thanks folks...As usual, great advice and useful research.
-SP

BB.

Re: Anybody have and recommend this clamp-on DC Meter?

This is the Sears DC Current Clamp meter (actually AC/DC and DMM functions).

-Bill

waynefromnscanada

Re: Anybody have and recommend this clamp-on DC Meter?

BB. wrote: »

This is the Sears DC Current Clamp meter (actually AC/DC and DMM functions).

-Bill

I got one of these meters last year, I believe thanks to BB's suggestion at that time, and I'm very impressed with it, especially considering the price!

BB.

Re: Anybody have and recommend this clamp-on DC Meter?

Oh darn... I forgot who--But one of the other smarter/more handsome posters here first provided the link to the Sears unit... It is a private label for Sears (it looks like) of this Extech MA220 at almost half the list price.

Ah--found the orginal poster "XRinger:

XRinger wrote: »

I got the Sears. If it wasn't what I wanted, Sears is just 2 miles away..

http://www.sears.com/shc/s/p_10153_12605_03482369000P?prdNo=3&blockNo=3&blockType=

I think that I paid about $60 for it.
It comes with a standard looking temperature sensor that works pretty well.
You do have to pay attention to the Zero.. It can drift out of cal on you.
Just have to keep hitting the button, when you see 0.1A floating in and out.
I guess it wouldn't be such a problem, if I was running more than 7A max.



They have one that looks just like this one, for about $40 /w no DC amps.
You don't want that one..

Like all DC Current Clamp type meters--Zero drift is an issue. You have to learn how to use the Zero Button--For some reason it is not obvious when using (disconnect clamp from any wiring. Push Zero button and a "ZERO" label will appear on the display. Now make your measurements and check zero every few minutes. You can also push the zero button with current flowing and it will then show changes from that reading +/-).

Also note that DC clamp meters will show + or - on the display depending on which direction the current is flowing. For AC measurements, there is "no direction" to the current flow.

I just keep posting the link because it is such a good deal for a functional DC Current Clamp Meter. Regular DMM's are typically limited to ~10 amps maximum and you don't have to expose your self to hazardous voltages/currents and "break open circuits" to insert DMM/Current type meters.

-Bill

Vic

Re: Anybody have and recommend this clamp-on DC Meter?

Appreciate the links to the Sears CO DC MM,

But, as I do not do any on-line commerce -- much too modern for me. And it is inconvenient getting to a Sears retail location. So, I snagged the Radio Shack similar CO DC MM:

http://www.radioshack.com/product/index.jsp?productId=4439164

For me, it is convenient to stop by an RS retail location and snag one for $65. Comes in a zippered pouch, and includes a Temp Probe FWIW. It, too, has a bit of a funky Zero fuction, but does work well.

But, without the links here, would not have known that there was a low-priced CO DC meter, so Thanks! Vic

Photowhit

Re: Anybody have and recommend this clamp-on DC Meter?

From the feed back, lots of people having issues zeroing that meter, might be the first thing to check out!

Usually there is some way to do a phone in for things found on internet, though that is slowly going away as people have discovered how secure internet sales can be if you are reasonably cautious.

Of couse some people (Like the water miser developer) will never trust on line CC or paypal wanting you to mail a check (I have 2 checking accounts but no checks!), while others will only do business via on line sales, to simplify life and avoid contact with customers...lol.

waynefromnscanada

Re: Anybody have and recommend this clamp-on DC Meter?

Re zeroing the dc clamp meter, I find it has to be zeroed whenever it's position relative to any nearby magnetic field, or even the earth's magnetic field is changed. As the meter depends on very slight changes in magnetic fields to come up with the currents being measured, I thus I took such sensitivity to be normal.

inetdog

Re: Anybody have and recommend this clamp-on DC Meter?

waynefromnscanada wrote: »

Re zeroing the dc clamp meter, I find it has to be zeroed whenever it's position relative to any nearby magnetic field, or even the earth's magnetic field is changed. As the meter depends on very slight changes in magnetic fields to come up with the currents being measured, I thus I took such sensitivity to be normal.

A meter could avoid that problem by having two identical sensors, one of which was measuring the field from the DC conductor and one which was far away. But that would be a lot more costly and would also still require calibration if used close to a magnet (where the field with no current would still be different between the two sensors.) In theory, a fully closed magnetic core loop would not sense any field (such as that of the earth) which did not result from current flowing inside the loop. Possibly the joining of the magnetic circuit as the clamp closes is not perfect or possibly the sensor is measuring more than just the field in the clamp magnetic circuit.

BB.

Re: Anybody have and recommend this clamp-on DC Meter?

Hall Effect Transistors (which is the magnetic sensor here--I believe) drift A LOT with time and temperature. It is the nature of the beast (silicon devices in general).

-Bill

Photowhit

Re: Anybody have and recommend this clamp-on DC Meter?

FWIW-My comment on problems rezeroing the meter had to do with the mostly poor reviews at Radio Shack.

Vic

Re: Anybody have and recommend this clamp-on DC Meter?

Has seemed to me that one of the largest factor is the nature of the split/insulated loop. The tighter the loop closes, the less effect external fields should have on the reading. The measuring loop must be insulated for safety. There could be a much "tighter" loop if there were no need for insulation, IMHO.

Remember the venerable Tektronix DC-25 Mhz (or so) scope probes. Had built-in automatic/manual Degaussing. Sure wish had one of those now.

Anyway, these little CO DC MMs are just fine for what they are. One needs to be careful about zeroing. Would guess that things will only improve over time, as the zero function is clearly the largest issue with them. Vic