Fluke 80K-6 HV probe - Page 1
Forum section: electronics / testgear

author: unicornio
author_rank: Contributor
timestamp: June 23, 2014, 06:28:42 pm
content: H, guysi just buy a 80K-6 from ebay:http://www.ebay.com/itm/351087822997?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649I need this probe to measure working voltages in ozone generation equipment with which I am working now. voltages are of the order of 4 or 5 Kv ... I've been looking for a long time fot it, but are rare to find used, and new are very expensive...I am now checking it state, that physically is perfect, but measuring the resistance between signal and ground, (the two bananas that you put in your multimeter) and it does not match with the 80K-6 manual data, where the value of the scheme comes:http://exodus.poly.edu/~kurt/manuals/manuals/Fluke/FLUKE%2080K-6%20Instruction.pdfit gives me a resistance of 86.65 K where in the manual says you have to give 75K ... i make the measure with some multimeters that i know, all are working well...I would like if anyone could measure yours and tell me the value that gives you. apparently the voltage divider is 1000:1 in both, so that the values ??should be very similar, although yours hold a much higher voltage ...i need to know if the voltage divisor is good, because if not, i can not to know what voltage i have!many thanks in advance,best regards!and good day, mate!...(I post some of this on another forum after i find that this user are banned, sorry for redundancy)

author: johansen
author_rank: Super Contributor
timestamp: June 23, 2014, 06:43:17 pm
content: could have been modified for a dmm with an input impedance of 557K ohms.or the 75M ohm resistor might be 86M ohms for a different model or something.

author: Fraser
author_rank: Super Contributor
timestamp: June 23, 2014, 09:27:09 pm
content: These units are not designed to be dismantled so modification would seem unlikely. I do have one in the lab but have no access to it tonight. In your position, I would test the probe on a known DC voltage from a power supply. Your meter will provide you with a reading that you can confirm accurate or not. 10V should give you a reading of 0.01V on your meter ;-). You could also use it to measure your city ac electricity supply and compare the reading with that provided by your meter direct.Do not trust schematics provided by the OEM unless you can confirm the revision of your equipment/probe is the same as that shown in the the schematic. Manufacturers reserve the right to change products.

author: unicornio
author_rank: Contributor
timestamp: June 23, 2014, 11:31:48 pm
content: thanks so much, johansen and Aurora for your helpQuote from: Aurora on June 23, 2014, 09:27:09 pmyou're absolutely right, Aurora, I can make some tests directly measuring low voltages and seeing their accuracy, I will do some tests tomorrow ...is easily removable, but I do not think that is modified. the voltage divider (or 'shunt') apparently is not touched, and is a printed circuit board, apparently ceramic, with printed resistors, so it appears to be original from FlukeQuote from: Aurora on June 23, 2014, 09:27:09 pmin the manual says this:"The 80K-6 represents a load of approximately 75 megohms to thecircuit being measured (13 mA per 1 kV). See Figure 1. To moreaccurately determine the load resistance, measure the resistanceof the 80K-6 at its voltmeter connector and multiply the measuredvalue by 1000"maybe I've misunderstood, or there is also the possibility that fluke has changed the values ??of the voltage divider, as Aurora says ...but the most important thing is that I can prove it easily by measuring DC voltages like 180V and 230VAC that I have available and I had not thought of. measuring voltages of this magnitude I can test it with complete accuracy.many thanks!good day, mates!

author: What_NZ
author_rank: Regular Contributor
timestamp: June 24, 2014, 01:55:55 am
content: I would like to know the out come of your tests too. Especially a confirmed value of the divider resister, the one in parallel with the Multimeter.Basically I would like to know if they calculate their divider resister with the input resistance (~10M) of the Multimeter in or out of circuit?

author: Tube_Dude
author_rank: Regular Contributor
timestamp: June 24, 2014, 02:24:59 am
content: As you already have dismantled it, take care and try don't contaminate it, or arcing can occur with the high voltages into play, as our fellow W2aew warn about it in his excellent video about high voltage probes...

author: aargee
author_rank: Frequent Contributor
timestamp: June 24, 2014, 07:25:40 am
content: My 80K-6 measures 78k across the two banana plugs.I imagine that the final value is set by Fluke when they calibrate the probe. I imagine there might be some different resistance effects when the probe is used in its applied voltage range and these would have been calibrated out.My probe is about 30 years old, and the datasheet online is for current units, so depending on the age of your unit, there might be some design differences.

author: unicornio
author_rank: Contributor
timestamp: June 24, 2014, 11:21:21 am
content: many thanks to all you guys!I've done some fast tests and the results have been very satisfactory. I think the probe measures very well and I have to be happy! ... ;-)))I checked with the probe directly on DMMCheck Plus 5VDC output, and the measure appears to be accurate, even if I only have two digits in the range of 200mV measuring 5VDC trough the probe, I think that's enough ... later will do tests with higher voltages in DC and AC and will put the results herei send some reference photos. what puzzles me when testing probe was this fluke scheme, but actually I think they only speak of relative values ??and also indicate how to measure each probe and find the corresponding value ...the two last images are to see what is the resistance of my probe on two conditions, one at open circuit and other, with short circuit between the two inputs...hope this helps!many thanks!good day, mates!

author: GreyWoolfe
author_rank: Unknown
timestamp: June 24, 2014, 02:12:04 pm
content: I just checked mine and it was 82.6K across the banana plugs.

author: unicornio
author_rank: Contributor
timestamp: July 01, 2014, 11:51:39 pm
content: Quote from: GreyWoolfe on June 24, 2014, 02:12:04 pmmaybe Fluke adjusted every divisor 'hand made' separately? ...I've done some tests with higher voltages and the result has been very good. in DC measures the probe appears to be very accurate ...CA will do tests now, that's another matter to consider. Fluke data regarding frequency linearity of 80K6 probe are not very encouraging, and I need to measure high voltages at high frequencies....someone has experience in this type of measures with this probe? ... ozone generators work by the method of electrical discharge (plasma) with voltages of the order of 5 kV and frequencies of about 10-15 KHz ...here are some images of this tests:

author: lowimpedance
author_rank: Super Contributor
timestamp: July 02, 2014, 12:11:03 am
content: So your measuring a 5kV AC voltage at 10-15kHz ??.Remember the meters upper AC volts frequency limits as well as the HV probes and take these into account with the actual measured value !!.Note the specs. for the probe will be approx. -30% @ 10kHz. You should characterize the probe/meter combo to be used against a known setup that gives the correct values .

author: unicornio
author_rank: Contributor
timestamp: July 02, 2014, 12:38:54 am
content: Quote from: lowimpedance on July 02, 2014, 12:11:03 amthanks so much for your post!yeah!...30% @ 10KHz!... I've seen that very bad figure in the 80K6 probe manual. I am aware that I need to make a characterization of probe-multimeter combo . I have only a good reference for AC, an Wandell & Goltermann SPM15 (a gem of precision) with which I hope to get some good reference ... it is a good source, level and frequency high accurate, for some AC volts at it max output, and up to 10MHz...the good thing about all this, is that I do not need to measure some KV with mV accuracy, but I like to have a notion as accurate as possible of what I have at hand ...:-)

author: Fraser
author_rank: Super Contributor
timestamp: July 02, 2014, 01:03:17 am
content: There are other types of HV probe, designed for use with oscilloscopes. They look the same as the common model that you have but terminate in a BNC connector and match to 1 MOhm scope inputs. These probes have a much wider bandwidth than the multimeter types. You would be able to see the excitation voltage waveform and measure it before and during flash-over.I have a couple of 15kV rated TECPEL probes and they have a stated bandwidth of 50MHz with a 1000:1 division ratiohttp://www.tecpel.net/HVP-15HF.htmlWorth keeping a look out for. I paid only GBP30 for two new TECPEL HVP-15HF's plus a Fluke 80K-40The seller had no idea of their purpose or value.

author: unicornio
author_rank: Contributor
timestamp: July 02, 2014, 09:44:25 am
content: Quote from: Aurora on July 02, 2014, 01:03:17 amyep, very good hv probe and very good info!...wehre you buy two TEPCEL AND AN 80k40 FOR 30gbp?...;-)I'll be very careful to find an offer like this! ... maybe on an ebay surplus...many thanks!good day, mate!

author: Fraser
author_rank: Super Contributor
timestamp: July 02, 2014, 10:23:04 am
content: Probes bought on e*ay... a case of being in he right place at the right time....I was well pleased when I found them. They came from a closed factory clearance.