Author Topic: Fluke 80i-410 clamp meter  (Read 5529 times)

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Offline BurningTantalum

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Fluke 80i-410 clamp meter
« on: September 13, 2015, 06:15:26 am »
I recently acquired a non-working Fluke 80i-410 DC & AC 400A clamp meter.
The output lead had been severed at the strain relief; the battery compartment was badly corroded and the batteries had obviously swollen to such a degree that the case was shattered; and the wires from the PCB to the battery case and the Hall effect sensor were compressed and partly severed in the rear lamination gap.
It was a real pig to dismantle as the hinge pin is an interference fit in the hard plastic (phenolic type) body and there was a danger of shattering the whole shebang. I am unsure of the vintage but it must be late 80s-early 90s (It was nice to see waxed lacing cord holding the output lead to the PCB- Ah, memories...)
I replaced the output lead and made good the wires, then temporarily soldered a 2X AA battery holder just to check if the meter worked. All seemed OK apart from a very small zero offset. On this meter because of the high range (5A - 400A) there is no user zero adjustment for offset. I wound ten turns of a test lead through the jaws and ran 2A through it- the reading appeared to be about 30% high. There are two multi-turn pots by the output lead which are accessible from the outside. I assume that they are for zero and span adjustment.
I spent an afternoon repairing the battery case with a sim card carrier, epoxy and stainless wire (from a chicken feeder!).
Before I dismantle it again to draw the schematic- does anyone know of any pitfalls or 'gotchas' in calibrating this type of meter? I intend to wind 100 turns of wire around a former (two plastic lids glued together or a small toy wheel) then pass 4A (AC & DC) through the coil with the jaws clamped around it.
Is this a valid process? For what I will use this for realistically it need not be better than 5%, but I would like to get it as good as I can.
Regards, BT
 

Offline BurningTantalum

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Re: Fluke 80i-410 clamp meter
« Reply #1 on: September 13, 2015, 06:23:42 am »
Actually the spec is usable max 2A - 600A at DC - 62Hz at +- 5% or 2A.
 

Offline SeanB

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Re: Fluke 80i-410 clamp meter
« Reply #2 on: September 13, 2015, 08:27:38 am »
Will work, and is probably used as the calibration in any case, as otherwise you need to make a transformer with a single turn secondary and drive it to that current in a single shorted loop. You are just removing the transformer shorted loop and core.
 

Offline HighVoltage

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Re: Fluke 80i-410 clamp meter
« Reply #3 on: September 13, 2015, 09:21:48 am »
That is exactly how I calibrated my high current Fluke probes and it worked very well.
 
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline SeanB

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Re: Fluke 80i-410 clamp meter
« Reply #4 on: September 13, 2015, 09:51:12 am »
I am running a wattmeter using a similar method, using a current transformer with a 10 turn primary and a 1 turn secondary, so as to increase resolution.  Primary up to 6A and secondary 60A, with the whole lot on the one phase for the voltage coil.
 

Offline BurningTantalum

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Re: Fluke 80i-410 clamp meter
« Reply #5 on: September 14, 2015, 04:40:26 am »
Thanks all, I'll get winding today !
 There is nothing but an LM10 op amp and a signal transistor in the Fluke so I assume that someone had an uneducated twiddle with a trim tool when the device stopped working due to the wires being pinched/severed.
It isn't a great mechanical design considering that it is a Fluke, but it was free to me.
Regards,  BT
 

Offline ModemHead

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Re: Fluke 80i-410 clamp meter
« Reply #6 on: September 14, 2015, 11:58:02 am »
The Fluke 5500A Current Coil might provide ideas for your setup...
https://www.google.com/search?q=fluke+5500a+coil&tbm=isch
 

Offline BurningTantalum

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Re: Fluke 80i-410 clamp meter
« Reply #7 on: September 14, 2015, 12:38:08 pm »
Thanks Mr ModemHead,
I had spotted the Fluke calibrator, and a line drawing of the coil which looks like a torus but I think it was just for clarity.
I found 17 metres of varnished copper wire on an old coil and wound an experimental 65 turns on a former. I tested it with 1A from a psu and borrowed a UT210E which read 65A dead. I zeroed the Fluke and set it for 65A and all seems well.
I have a couple of speaker Xover coils in the parts bin which seem to be 100 turns-ish. With 0.5A through, the Uni-T read 51A (100A max for the meter), and with 1A the Fluke read 98A. I will wind a 200 turn or more tomorrow and fine tune the Fluke.
Thanks again,  BT
 

Offline ModemHead

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Re: Fluke 80i-410 clamp meter
« Reply #8 on: September 14, 2015, 05:40:52 pm »
Sounds like you might wind up with a successful repair.   :-+

From appearances of the Fluke unit, I can't help but think one could possibly turn a Slinky toy into a calibration jig...
 

Offline BurningTantalum

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Re: Fluke 80i-410 clamp meter
« Reply #9 on: September 15, 2015, 02:31:24 am »
C'mon Mr MH - this is a serious forum. Everybody knows that a Slinky isn't insulated... now where is my transformer varnish...
 

Offline ModemHead

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Re: Fluke 80i-410 clamp meter
« Reply #10 on: September 15, 2015, 12:00:23 pm »
Little duct tape'll fix that right up.  - Red Green
 


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