Gauss meter and current measurement

[willib]

the first shot is my hall sensor , with a coating of fiberglass (epoxy) over the actual sensor, to keep it from bending or breaking the wires

i cut a slot on the ferrite ring to fit the sensor in . just like Jim did

there are about 25 turns of 0.045"dia wire on the ring

i ground the burrs(from the manufacturing process) off the ring to keep it from shorting out the turns

the Voltage output of the sensor is proportional to the flux the sensor sees

somone with a fluxmeter could correlate the readings i got (so i could read the output in tesla(not required but might be fun and interesting)

like if for instance with 2.12A going through the 25 turn coil , it was reading 332milli Volts , just about half scale , because the sensor puts out 638mV when under or in the magnetic field of my minigens magnets

i suppose it might go higher if i was to put over 4A through the coil , but i have not tried that yet.

...I(A)...V(mV)

 .005--14.4

 .31-- 57.3

 .52-- 94

 .6--- 107

 .81-- 139

 1.05- 175

 1.32- 217

 1.61- 260

 2.12- 332

i graphed the data and the curve was a straight line , so i extended the graph to read ~ .638V and it came out to ~ 4Amps

so with the sensor on the output of the minigen , boosted to ~25Volts and 4Amps readable current , i should be able to measure 100 watts output from the minigen,i hope that its not to optimistic:)

http://www.otherpower.com/images/scimages/2965/Picture_060.jpg

the second shot is the RS232 cable connected to the pic u controller i made it a clickable link because of the size~135KB

[maker of toys]

nice job of making a home-brew current sense transformer.  What excitation voltage are you applying to your Hall element?

(come to that, what part are you using?)

Have you considered moving the coil down closer to the gap?  I'm curious to see how (IF) it would affect sensitivity.

Any thoughts on using a ferrite bar (like out of an AM radio? in place of the gapped toroid?

[AequalB]

willib

http://www.thebackshed.com/Windmill/charger1.asp

http://www.thebackshed.com/Windmill/images/charger-cct.gif

heh... 741 ...?!!

[AequalB]

about home-brew gauges of the Hall

http://www.rcgroups.com/forums/showthread.php?t=307133&pp=15

[AequalB]

willib,

why a ferrite ring, instead of from transformer iron?

[stephent]

Actually the whole thread is kinda informative...browse the whole thread sometime especially page 2 post 20. Now that's interesting about the temp test.

But page 2 post 30 is interesting too, dangerous as heck too.

Lots of meat and info in the whole thread after sorting out some chaff on mags--hall effects, etc.

[willib]

Dan ,i'm using a 1.5 volt AA cell

i'm not sure exactly what part it is i got it out of a CD ROM drive , you get three out of each CD Drive

i imagine that a ferrite bar would work also

A=B, i found that link a while ago , thanks for reposting it, i spent hours reading that post, its really well done

[Ungrounded Lightning Rod]

Don't know about willy - but I'd use a ring because it's better at confining the field and not coupling to adjacent stuff than a set of transoformer lams.  That's a good characteristic in an instrument sensor.