Measuring current through a DC fan

[wardenclyffe]

Hey guys, I am almost embarrassed to ask this question, but is there some special way to measure current through a DC fan? I pulled a fan out of my older stereo that is rated at 12Vdc, 0.8A to use elsewhere. I hooked it up to a 12V wall adapter just to see if it still worked and it did. When I tried to measure current with the meter in series with the power rail, the fan would not operate and the meter read 0A. The fan worked fine when I tried it at 12V again and using lower voltages as long as the meter was not also connected. I don't have much knowledge at all about motors and fans so I was wondering if someone could tell me what I am doing wrong here.

Help is always much appreciated!!

[Kiriakos-GR]

1) Open the DMM and check the fuse inside, probably is burned out.
2) Post a picture of your DMM.

[Simon]

Presumably the meter was set for current and you had the probes in the right sockets

[Zero999]

Presumably the meter was set for current and you had the probes in the right sockets

Or maybe not and that's the problem.

This could be worse, some nubes try to measure the current capacity of their power supply/battery by connecting their meter set to measure current across the output terminals.

[sacherjj]

If you had the probes in the Voltage position, you introduced a very high resistance in line, which would make this happen.  (The open circuit for a current blown fuse is an even higher resistance which is also a good guess.)

[wardenclyffe]

If I managed to do that, and the more I think about it that is probably what happened, I think I may just quit this electronics stuff altogether. Thanks, guys.

[sacherjj]

If I managed to do that, and the more I think about it that is probably what happened, I think I may just quit this electronics stuff altogether. Thanks, guys.

The only one to be really worried about is measuring voltage with the current setup.  My dad killed my Heathkit DVM with that move.  They didn't have a 10A fuse, just a 10A trace that line voltage vaporized.  

[w2aew]

Another possibility is that the drop-out voltage of the DMM in current measurement mode might be too large, and not leave enough voltage for the fan to start/run.  This could especially be the case if the fan is a Brushless DC motor which includes some driver electronics buried in the fan.  Try measuring current on the highest current scale on the meter to minimize the dropout voltage...

[Kiriakos-GR]

People you are replying to some one who had introduced him self in this forum as
 " my name is Chris and I am a recent graduate in electrical engineering. "

Oh well yes quit that stuff .. save your self    

[Mechatrommer]

better to take phd?

[Semantics]

I think I may just quit this electronics stuff altogether. Thanks, guys.

Eh, don't be so hard on yourself. One of the first things I remember doing was measuring a car battery voltage except I didn't pay attention and grabbed a meter with probes in the mA sockets. Oooh yeah, too cool for school, yo. 

Think of it as a $7 lesson learned: cost of a new fuse, and move onwards.

[MrPlacid]

... that is probably what happened, I think I may just quit this electronics stuff altogether. Thanks, guys.

You can't. Do you think you can just toss your interest out the window that easy? Soon, you'll have a compulsive disorder and end up buying boat loads of multimeters like the rest of us here. Haha... this is your future and you can not change it!