Megger KF-875 User manual

Megger KF-875
Moisture Meter
User Guide (v0816)

Megger KF-875
2

Megger KF-875
3
Contents
Chapter 1 Introduction------------------------------------------------------------------------5
1.1 Instrument Description-----------------------------------------------------5
1.2 Principle of Measurement-------------------------------------------------6
1.3 Instrument Connections--------------------------------------------------- 7
Chapter 2 Safety Information--------------------------------------------------------------- 8
2.1 General Safety Points------------------------------------------------------8
2.2 Electrical Safety------------------------------------------------------------- 8
2.3 Solvent and Chemical Safety-------------------------------------------- 8
2.4 Recycling and Disposal----------------------------------------------------8
Chapter 3 Instrument Setup-----------------------------------------------------------------9
3.1 Receiving a Megger KF-875--------------------------------------------- 9
3.1.1 Packaging---------------------------------------------------------9
3.1.2 Checks-------------------------------------------------------------9
3.1.3 Location----------------------------------------------------------- 9
3.2 Connecting the Power Supply------------------------------------------- 9
3.3 Setting Up the Glassware-------------------------------------------------10
3.3.1 Glassware Assembly-------------------------------------------10
3.3.2 Connecting to the Megger KF-875------------------------- 10
3.3.3 Filling and Changing Reagents------------------------------11
3.4 Loading the Printer----------------------------------------------------------13
3.5 Connecting a USB Device------------------------------------------------ 14
Chapter 4 Basics of Operation-----------------------------------------------------------15
4.1 Switching ON and OFF---------------------------------------------------15
4.2 Setting the Date and Time-----------------------------------------------15
4.3 Preconditioning------------------------------------------------------------- 16
Chapter 5 Running a Test----------------------------------------------------------------- 17
5.1 Example Applications----------------------------------------------------- 17
5.2 Water Standard Test------------------------------------------------------ 17
5.3 How to Run a Test--------------------------------------------------------- 17
5.4 Drift Rate Compensation------------------------------------------------- 18
5.5 Overtitration------------------------------------------------------------------19
Chapter 6 Results---------------------------------------------------------------------------- 20
6.1 Printout Explanation------------------------------------------------------- 20
Chapter 7 Maintenance--------------------------------------------------------------------21
7.1 Reagent Life-----------------------------------------------------------------21
7.2 Cleaning the Glassware--------------------------------------------------21
Chapter 8 Technical Specifications--------------------------------------------------- 23
Chapter 9 Parts List-------------------------------------------------------------------------24
Chapter 10 Troubleshooting---------------------------------------------------------------25

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Chapter 11 Conformity and Warranty-------------------------------------------------- 26
11.1 Declaration of Conformity--------------------------------------- 26
11.2 Quality Control----------------------------------------------------- 26
11.3 Customer Support and Service--------------------------------26
11.4 Warranty-------------------------------------------------------------27
11.5 Warranty Exemptions---------------------------------------------27

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Chapter 1 Introdu tion
1.1 Instrument Description
The KF-875 model has a small footprint, is easy to use, and supplied complete with a
specifically designed low drift cell which is also suitable for outdoor use. The built-in
battery and carry case, provide the versatility required by the laboratory and also the ease
of use and portability required by the field engineer. Preprogrammed for typical
transformer oil analysis calculation parameters (injection volume of 1.0ml and SG of
0.875)
Aquamax KF reagents have been specially formulated for use with KF-875 titrators.
Reagent A (anode) is suitable for most routine applications and is especially useful for
water content determination of oil samples, e.g. transformer oils, crude oils, etc. This
anode reagent is supplied in “single shot” bottles of 100ml – No measuring of volumes
required – No mixing of other solvents required. Reagent C (cathode) is supplied in
“single shot” 5ml vials.
The carry case provides the portability required by the field engineer. The KF-875 can be
transported, complete with glassware assembled, ready for immediate use on arrival at
destination. Power cords, syringes, etc., can all be carried inside the carry case lid which
has a special compartment for this purpose.
To obtain the full benefits that this instrument can offer it is recommended that you read
this user manual before assembling the unit.
(All KF-875 power supplies are double insulated units that do not need an earth (ground)
connection. These units are sealed and conform to CSA(LR84459), UL listings and CE
requirements. KF-875 titrators only require a low voltage 15V input to the electronic /
control circuitry. The moulded plastc casing of the instrument also provides additional
insulation.)

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1.2 Principle of Measurement
Karl Fischer titration is simply a means to measure water content of samples. Modern
instruments, such as the Megger KF-875, use the Coulometric principle, whereby the water
present in the sample is coulometrically titrated to a predefined end point at which there is a
minute excess of free iodine present. Stoichiometrically, 1 mole of water will react with 1
mole of iodine, so that 1 milligram of water is equivalent to 10·71 coulombs of electricity.
Combining the Coulometric technique with Karl Fischer titration, Megger KF Titrators
determine the water content of the sample by measuring the amount of electrolysis current
necessary to produce the required iodine. This is an absolute technique which does not
require calibration of the reagents.
SO
2
I
2
+SO
2
+3C
5
H
5
N+H
2
O → 2C
5
H
5
N.HI+C
5
H
5
N
O
SO
2
SO
4
CH
3
C
5
H
5
N +CH
3
OH → C
5
H
5
N
O H
2l ¯ - 2e →l
2
Using the latest pulse current technology and our patented “ACE” control system, (Patent
No.GB2370641), the Megger KF-875 automatically selects the appropriate titration speed
dependent upon the amount of water present in the sample. The titration speed is reduced
as the end point is approached, and when the titration is completed the instrument prints out
and displays the results.

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1.3 Instrument Connections
Various ports are located on the back plate of the instrument. Below is a list of ports that can
be found:
(1) Power Supply Port
The power supply port is for connecting to an 18V mains power supply, using the
supplied power adaptor.
(2) RS232 Port
For updating Titrator software, connecting to other equipment for remote controlling
(software specific protocols to be provided).
(3) USB/A Port
For exporting results data to a Removable Flash Drive (memory stick), when running
sample tests in the field or remote locations, and subsequent transfer to PC at a later
date for loading onto Results Manager files.
(4) USB/B Port
For connecting directly to PC to export data to Results Manager and enable results to be
saved on files for future reference. (See Results Manager User Manual section).

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Chapter 2 Safety Information
2.1 General Safety Points
This product is in conformity with the EU Directives 2004/108/EC and
2006/95/EC. This is based upon the compliance of the products with the
harmonised standards: BS EN 61000-6-1:2007; BS EN 61010-2-030:2010;
and BS EN 61326-1:2013.
This product is manufactured in accordance to RoHS following the EU
Directive 2011/65/EU; it does not contain any of the restricted substances in
concentrations and applications banned by this directive.
2.2 Electrical Safety
The Megger KF-875 Moisture Meter complies with the international
standard IEC 61010. Only operate this instrument within the mains
voltage supply that is specified on the back of the instrument, an
incorrect mains supply can damage the instrument. Never open the
housing of the instrument, only GR Scientific personnel who are trained
to service the instrument can open the housing. There is risk of
electrocution if live components are touched.
Always ensure the instrument is disconnected from the mains power supply when
connecting or disconnecting cables from the back of the instrument, as electrostatic
discharge can build up.
2.3 Solvent and Chemical Safety
When using flammable or irritant solvents and chemicals, follow suitable
safety measures to protect yourself and others around. Always use the
instrument in a well ventilated area, clean up spilled fluids immediately,
and keep flame sources away from the work area. Always follow the
safety instructions of the chemical manufacturer and apply the correct
countermeasures that are required.
2.4 Recycling and Disposal
This instrument is covered by the WEEE (Waste Electronic and Electrical
Equipment) Directive 2012/19/EU to prevent the negative and harmful
effects on the environment and public health. For more information on
how to dispose of the instrument safely, please contact your local
authority, your local waste disposal company or Megger directly.

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Chapter 3 Instrument Set Up
3.1 Receiving a Megger KF-875
3.1.1 Packaging
The Megger KF-875 is packaged in suitable protective packaging to ensure that no damage
occurs during transit, only this packaging is suitable for the safe transportation during transit.
Please keep this packaging as transit of the instrument may need to occur in the future.
3.1.2 Checks
Once you have received the instrument, immediately check to make sure that there is no
damage and no parts are missing. A delivery note will be included within the package to use
to compare with the shipment.
Ensure that inside the shipment has a calibration certificate for the instrument, if not please
request this from the manufacturer.
3.1.3 Location
Locate the instrument within the work area where it is free from excessive:
−vibrations
−direct sunlight
−contamination from chemicals
−explosive environments
−corrosive atmospheres
−major temperature fluctuations
3.2 Connecting the Power Supply
The Megger KF-875 is powered by an external mains source, with a power pack to ensure
this connection is the correct voltage of 18V DC for the instrument.
Damage may occur beyond repair and the user may be subjected to electric static shocks if
the incorrect power is supplied.
Note: Refer to Chapter 2 for more safety information.
To avoid risk of electrocution, make
sure the I/O switch is set to OFF
before connecting the power supply.

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3.3 Setting Up the Glassware
3.3.1 Glassware Assembly
3.3.2 Connecting to the Megger-KF 875 Moisture Meter
(1) Position the titration vessel on the Titrator.
(2) Position the electrodes on the
titration vessel and tighten by
hand.
Note: The glass joints do not require PTFE
sleeves or grease. The special screw fittings
seal the vessel from the atmosphere and are
easily released, even after several weeks.

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(3) Connect the generator and detector leads to the vessel
and then to the BNCs.
(4) Place the stirrer bar inside the titration vessel.
(5) Fit injection septas into the injection port caps and screw
tightly by hand onto the injection ports.
(6) Position the drying tube with desiccant and tighten by
hand.
The assembled titration cell is now ready to be charged with reagents prior to use. Please be
sure to assemble correctly every time the cell is cleaned or re-filled. It is recommended that
the Titrator is NOT switched on until after the titration vessel has been charged with
reagents. This will avoid damage being caused to the electrodes by the stirrer bar. Avoid
twisting the electrode leads otherwise they may become damaged.
3.3.3 Filling and Changing Reagents
Megger KF-875 Titrators have been designed to operate with all major Coulometric Karl
Fischer reagents. For most routine applications generator electrodes with frit/diaphragm are
used in conjunction with 100ml of anode reagent and 5ml of cathode reagent. We strongly
recommend using Aquamax KF A and C Reagents as these have been specially formulated
for oil samples.
When analysing Transformer oils, Crude oils and other petroleum products, there are
specially formulated anode reagents which contain other solvents to improve sample
miscibility and solubility are recommended. There are also single Coulometric reagents
available for use with fritless generator electrodes. Although we do not recommend these for
oil sample analysis.
Note: When analysing samples of Ketones, amines or others which may interfere with the
reaction it is advisable to use specialised reagents which can be obtained from various
suppliers.

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Although reagents can be poured into the titration vessel whilst it is located on the Titrator,
we recommend that the vessel, electrodes and electrode leads are removed from the
instrument whilst this procedure is performed to avoid reagent spillage onto the instrument
casing.
Note: Any spillage onto the instrument casing should be wiped off immediately to avoid
damage or staining.
Remove the drying tube and injection septa. Using the funnel
supplied, charge the titration vessel with 100ml anode reagent
(this is approximately to the bottom line on the vessel).
Also using the funnel, charge the inner chamber of the generator
electrode with 5ml of cathode reagent. (This is not required if
using fritless generator electrode).
Note: It is not necessary to clean the funnel between reagents.
Reconnect the drying tube and injection septa so that the titration vessel is sealed from
ingress of atmospheric moisture.
Locate the complete titration vessel onto the Titrator and connect
the electrode leads onto the appropriate sockets
There are some bi-products formed in the cathode chamber which
can react with the iodine in the anode chamber and this can cause
longer preconditioning times. It is advisable to have the cathode
reagent 2- 3mm lower than the anode reagent when first charging
the titration vessel to speed up preconditioning.
The Megger-875 Titrator is now ready to be switched on.

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3.4 Loading the Printer
To load the paper into the printer, first open the paper roll holder lid above the print head and
remove the old roll and rollers. Now fit rollers to new paper roll, load as shown and insert the
paper into the slot at the rear of the print head. As soon as the printer sees the paper it will
automatically load it. To avoid damage to the printer mechanism it is advisable to only use
the correct part number thermal paper rolls.
Cut the end of the paper roll at
a slight angle as shown. This
will make it easier to feed into
the printer
mechanism
.
The mechanism has optical
sensors which detect the
paper and will auto feed.
Schematic of paper feed.
Fit the paper bobbin onto both
sides of paper roll.
Locate paper roll into the
compartment.

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3.5 Connecting a USB Device
To use the memory store, insert Flash Drive into USB port A, the Titrator will see it and a
symbol will appear on the display.
The symbol will appear blacked out while the drive is being written to and then clear when
idle.
The drive should only be removed when in the idle mode.
To read data saved on the drive insert it into a PC USB port. Start Results Manager, load
selected file and then save in the format you require. Refer to Chapter 7 Results Manager.

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Megger KF-875
v2.6n Press START
Set Date/Time:
DD/MM/YYYY HH:MM:SS
Chapter 4 Basi s of Operation
4.1 Switching ON and OFF
The Megger KF-875 Moisture Meter has one I/O switch and is powered by either a mains
power supply using an adaptor, or a built-in battery for power.
Note: Refer to Chapter 3.2 for power supply connections.
4.2 Setting the Date and Time
(1) Switch on the Megger KF-875 and wait for it to display the following:
(2) Hold down the [START] key until the Megger KF-875 displays:
(3) Use the [ . ] move the cursor across the screen.
(4) Use the numerical keys to set / alter the required number.
(5) When completed press the [ENTER] to save the changes and exit.
To avoid risk of electrocution,
make sure the I/O switch is set to
OFF before connecting the power
supply from a mains source.

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Megger KF-875
v2.6n Press START
KF-875 xxxx µg
||||||||| 4 Precondition
Dft xxxx µg
| Drift Test
Dft = 0 xxxx µg
| Ready
4.3 Preconditioning
(1) Assemble glassware (see Assembly Instructions)
(2) Charge vessel and generator electrode with reagents (see Filling & Changing
Reagents)
(3) Locate assembled titration vessel onto the Megger KF-875
(4) Connect the electrode leads
(5) Connect mains lead / power cord
(6) Switch ON (using switch on rear panel) and wait for display to show:
Note: If required adjust the stirrer speed using the arrow keys on the front of the instrument.
(1) Press [START] and allow the instrument to precondition (equilibrate).
At the end of the precondition period the display will show:
After the initial drift has been calculated, in micrograms of water per minute, the Megger KF-
875 is ready for operation.
The background drift value will usually slowly decrease with time as the titration vessel
becomes drier and more stable. Although it is possible for the Titrator to be used at high drift
values, it is advisable to wait until the drift value is below 20 µg/minute, and stable, before
commencing, especially for low water content samples in the ppm ranges.
The lower and more stable the drift – the more accurate the result.
Detector Signal
Titration Speed
Microgram Count

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Chapter 5 Running a Test
5.1 Example Applications
Transformer/Insulating Oils
(ASTM D 1533, BS EN 60814, IEC 60814)
Due to the viscosity of these samples, and the fact that typical water content levels are in the
range 5 – 40 ppm, it is usually necessary to inject sample volumes of 1 ml. This means that
up to 50 samples would fill the titration cell. Provided that the other criteria governing reagent
life, (total water titrated and reagent age), have not been reached, then it is possible to
switch off the Titrator and allow the oil to separate from the reagent. The oil can then be
siphoned off and the instrument switched on again. After this operation it may take up to 30
minutes before the instrument settles down to a stable baseline. If it takes longer than 30
minutes then it is advisable to clean the cell and recharge with fresh reagents.
5.2 Water Standard Test
In principle, standardization of a Megger KF-875 is not necessary since the water titrated is a
direct function of the coulombs of electricity consumed. However it is recognised that
reagent performance can deteriorate with use over time and it is recommended that the
Titrator is regularly monitored by introducing a known quantity of water that is representative
of the typical range of water concentrations being determined in samples. Several of the
ASTM methods for water content of crude oil and petroleum products suggest injecting
between 1.0 µl and 10 µl distilled water to check reagent performance.
Each of these methods requires that the result be recorded in micrograms of water, not as a
calculated ppm or percentage.
5.3 How to Run a Test
Example: Transformer oil sample by V/SG
Result Format = mg/kg
Calculation Mode = V/SG
Sample Volume = 1.0 ml
Sample SG = 0.875
ANALYSIS METHOD
(1) Confirm that KF-875 is in Ready mode.
(2) Flush 1.0ml syringe several times (minimum 6 times) with sample.
(3) Fit luer needle and flush through with sample.
(4) Draw sample into syringe beyond the 1.0ml marking.
(5) Invert syringe so that any air bubbles can be ejected through the needle and adjust
syringe plunger to the 1.0 ml mark.
(6) Wipe off excess sample from outside of needle using a clean, dry tissue or paper
towel.

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Drift Warning
START to continue
(7) Pierce needle through injection septa of titration vessel (1 – 2 cm).
(8) Press START.
(9) Push needle into anode reagent and inject sample.
(10) Withdraw needle from titration vessel.
(11) Read result, in mg/kg (ppm) water, on display and printout.
(12) Repeat steps 2 – 11 if duplicate result required.
5.4 Drift Rate Compensation
At the start of any titration, the drift value in the top left corner of the screen (in micrograms
per minute), is stored in memory. This ensures that the displayed result is corrected for any
ingress of atmospheric moisture during the titration period.
Whilst in the Ready condition, the Megger KF-875 continually compensates for any drift
caused by atmospheric moisture ingress or reagent decomposition and displays this
information, which is updated every 10 seconds. If the drift value is above 30 µg /minute the
display will show “Drift Warning START to continue.” This is a warning that the value is high,
however the instrument can still be used by simply pressing [START] to continue.
Provided the drift rate is stable then it usually acceptable to continue operation. The
Aquamax titration cell design can provide drift values down to less than 5 µg /minute but can
also operate at much higher values. The maximum drift value is 60 µg /minute but we
recommend operating up to a maximum of 25 whenever possible.
If the drift value is above 60 µg per minute the display will read:
“EXCESS DRIFT - SEE INSTRUCTION MANUAL”
Most common causes of excess drift are:
−Titration vessel not properly sealed (check septa & fittings)
−Reagents almost depleted (clean & recharge the cell)
−Sample introduced before pressing [START] key
−Trace moisture on cell walls
If excess drift occurs, switch the instrument off, remove titration cell from clamp, gently swirl
the anode reagent around the cell walls, replace cell in clamp, switch instrument on and
allow to precondition.

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OVER TITTRATION – SEE
INSTRUCTION MANUAL
5.5 Overtitration
If the detector electrode senses too much Iodine in the titration cell, usually caused by
instrument being left unoperated for a long period, the display will read :-
“OVERTITRATION - SEE INSTRUCTION MANUAL”
Simply add 3 - 5 microlitres of water, or a small amount of a known wet sample, until the
detector signal bars on bottom left of display are activated. Then the instrument will
automatically carry out its precondition.

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Chapter 6 Results
6.1 Printout Explanation
The KF875 prints the calculated results in ppm (mg/Kg) along with time and date of the
titration and run number. The KF875 automatically increments the next run number every
time you press the start button. The run counter is reset to zero when power is switched off
and back on again. A duplicate set of results can be printed out simply by holding down the
Start button for 3 seconds. Results memory is cleared after duplicate print out or when
power is switched off.
Print Out Example
−Titrator model
−Software version
−Titrator serial number
−Date Titrator calibrated
−Date sample run
−Run no. and time of analysis (F = generator with
frit)
−Nett microgram count (after drift correction)
−Drift value at start of titration
−Result format selected
−Calculation mode selected
−Sample volume
−Sample density
−Calculated result water content
−Subsequent runs of the same sample and
calculation parameters show run number, run
time, nett count.
−Drift value.
Megger KF 875
V xxxx
Serial No. 71000
Calibra ed DD/MM/YYYY
Run Da e
Run: 1 Run Time F
Ne Coun 0.0 μg
Drif 00
Resul Forma mg/kg
Calcula ion Mode V/SG
Volume 1.0000 ml
Densi y 0.8750
Res: 0.0 mg/kg
Run: 2 Run Time F
Ne Coun 0.0 μg
Drif 00