Powering a Fluke multimeter from a Constant Power Supply

[TheRain]

Hi,

I work for a software company and recently we have had to start doing
some electronics testing in relation to our software.

The problem we are running into is that we have these mid-grade (~
$500) multimeters run out of batteries before the hardware we are
testing does, and the test we are running is to benchmark current draw
over the life of the battery. The multimeters run on 6 AA batteries
in series which should be about 9V if each one is 1.5V. When we
connect our Constant power supply to it's battery terminals and try to
run it with 9V, the meter does not turn on. I've tried overpowering
it a little by running 10V but this also did not work. Our CPS is 3A
so that should not be the problem.

I'm wondering, what could cause this? Is there a solution for it?

Any thoughts or advice would be very helpful!

Thanks,

Collin

 

[Tom Biasi]

Hi,

I work for a software company and recently we have had to start doing
some electronics testing in relation to our software.

The problem we are running into is that we have these mid-grade (~
$500) multimeters run out of batteries before the hardware we are
testing does, and the test we are running is to benchmark current draw
over the life of the battery. The multimeters run on 6 AA batteries
in series which should be about 9V if each one is 1.5V. When we
connect our Constant power supply to it's battery terminals and try to
run it with 9V, the meter does not turn on. I've tried overpowering
it a little by running 10V but this also did not work. Our CPS is 3A
so that should not be the problem.

I'm wondering, what could cause this? Is there a solution for it?

Any thoughts or advice would be very helpful!

Thanks,

Collin

A $500 dollar multi meter usually has an external power provision. If your
unit is truly 9 volts and you are supplying 9 volts with enough current I
can only guess that you are not connecting it properly. Make sure the supply
is not going into current limiting.

Tom

 

[TheRain]

This meter doesn't seem to have any available accessories to run from
anything but it's batteries.

Current limiting is something I thought of this morning and seems like
a possibility. I think that in all cases we had the power supply
making all 3A available.

I'm fairly certain we are connecting it properly. Plus and minus are
clearly marked on the battery pack and we lined these up to the
contacts multiple times to make sure we were tapping the right ones.

Thanks for your help, thoughts and suggestions!

 

[TheRain]

I just mean a DC variable power supply, such that you would use in a
lab etc.

 

[TheRain]

BTW, which meter is it?

They are Fluke 289's I just put in a call to Fluke as well to see if
they had any thoughts. Most likely they won't have anything
"official" to say about connecting a power supply in that manner
heh.

 

[Rich Webb]

They are Fluke 289's I just put in a call to Fluke as well to see if
they had any thoughts. Most likely they won't have anything
"official" to say about connecting a power supply in that manner
heh.

What you've described should work, assuming that your polarity is right
and the power supply isn't going into current limit. AFAIK, there's no
"cell present" sense switch or similar.

I've got one of the relatives of that series (189? 187? forget which
just now) and it is indeed a battery hog. Nice meter, otherwise. Fluke
does provide an option for a C-cell battery pack for additional capacity
(that works with the 289, as well), so that's another option:
http://www.tequipment.net/FlukeBP189.html

Fluke also has a pretty good web forum, for an additional resource:
http://www.flukecommunity.com/forums/index.php

 

[TheRain]

Thanks very much for the link to the fluke site. I'm going to check
if there's a possiblity that our power supply isn't supplying the 3A I
expected or something like that.

 

[Rich Webb]

Thanks very much for the link to the fluke site. I'm going to check
if there's a possiblity that our power supply isn't supplying the 3A I
expected or something like that.

If the meter is trying to pull more than 3 A then something is seriously
wrong. The 189 here only draws about 20 mA at 6 V (17 - 23, depending on
what it's doing) and the 189 is reputed to be the power hog in the
family.

 

[Phil Allison]

"TheRain"

I work for a software company and recently we have had to start doing
some electronics testing in relation to our software.

The problem we are running into is that we have these mid-grade (~
$500) multimeters run out of batteries before the hardware we are
testing does, and the test we are running is to benchmark current draw
over the life of the battery. The multimeters run on 6 AA batteries
in series which should be about 9V if each one is 1.5V. When we
connect our Constant power supply to it's battery terminals and try to
run it with 9V, the meter does not turn on.

** Suspect that there are more than 2 internal connections to that 6 cell
stack.




...... Phil

 

[whit3rd]

The problem we are running into is that we have these mid-grade (~
$500) multimeters run out of batteries before the hardware we are
testing does, and the test we are running is to benchmark current draw
over the life of the battery.  The multimeters run on 6 AA batteries
in series which should be about 9V if each one is 1.5V.   When we
connect our Constant power supply to it's battery terminals and try to
run it with 9V, the meter does not turn on.

It might be a 9V supply, or it might be a +/- 4.5V supply. Have you
verified that the cells are in series, and that the meter doesn't
connect
to the midpoint(s) of the series?