Amprobe AMB-25 Operating Manual

INSULATION TESTER

AMB-25

INSTRUCTION MANUAL

sACm:

MEM
READ

HOLD

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1. SAFETY INFORMATION

The circuit under test must be de-energized and isolated before

connections are made except for voltage measurement.

Verify operation prior to measuring hazardous voltages (voltage

above 30V AC rms, 42V AC peak and 60V DC).
Do not touch the Circuit connections during a test.
Disconnect the live test lead before disconnecting the neutral

test lead.

After insulation tests, to protect electric shock, capacitive circuits

must to be discharged.

Do not use the meter if the low battery indicator (

showed.

Test leads (including crocodile clips) must be in good order,

clean and no broken or cracked.

Do not use the meter if it looks damaged.
Do not use the meter around explosive gas, vapor or dust.
Do not push test button before all connection and preparation is

done. The instrument must only be used by suitably trained and

competent persons.
Do not use the meter with any parts or cover removed.
Do not use the meter in a wet environment.

U.S. PAT. NO. 478,017
JAPAN PAT. NO. 1180870
CHINA PAT. NO. ZL02367250.1

Warnings and Safety symbols:

Caution refer to this manual before using the meter.

Dangerous voltages.

Meter is protected throughout by double insulation or
reinforced insulation.

Comply with IEC1010-1
When servicing, use only specified replacement parts.

1

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) is

2. SPECIFICATIONS

Ω

2-1 General Information

Environment conditions :

c Installation CategoriesⅢ 1000V

d

Pollution Degree 2

e Altitude up to 2000 meters
f Indoor use only

Safety Meets of IEC61010-1 and IEC61557

Display : Dual display, 3-3/4 Digital readout with analog bar

Sampling Rate : 2.5 sample/sec.

Manual data Memory and Read : Memory capacity 9 set.

Over Range Indicator : “

Low Battery Indication :

Operating Temperature and Humidity：

Temperature Coefficient : 0.10 x (specified accuracy)/ ℃

Storage Temperature and Humidity :

Battery : 6 x 1.5V Size “AA” battery.

Fuse : 6mm x 32mm (0.25 x 1.25 inch), 0.5A 1000V, Fast Acting.

Dimensions : 235 (L) x 116 (W) x 54(H) mm ,

Weight : Approx. 520g (1.15 LB), include battery

Accessories : Test leads, 6pcs battery, Holster, operation manual.

indication.

” will be displayed.

BT

The (

below the operating voltage.

0℃ to 50℃ (32℉ to 122℉) below 80% RH (noncondensing).

-10℃ to 60℃ (14℉ to 140℉) below 70% RH (noncondensing)

) will be displayed when the battery voltage drop

(9.3”L x 4.6”W x 2.1”H)

2

2-2 Electrical Specifications

Accuracies are specified as:

±(...% of reading + ...digits) at 23℃ ±5℃,below 80% RH.



Insulation Resistance

Range Resolution Accuracy Test Voltages

40MΩ/400MΩ

400MΩ/1000M

/500V

400MΩ/ 2000M

/1000V

Analog Bar Graph

Nominal Current



Resistance & Continuity (<40Ω)

Range Resolution Accuracy

Ω

999.9

0.1Ω

40MΩ: 10 K

Ω

400MΩ:100 K
4000MΩ: 10M

Ω

3%+5

Ω

(<1000M)

Ω

5%+5

(>1000M)

0 to 4000MΩ

Max. open Circuit

1%+2 3V 1000Vrms

3

250V+20% ~ -0%

500V+20% ~ -0%

1000V+20% ~ -0%

≧

1mA

Voltage

Overload

Protection

3. PARTS & CONTROLS

MEM
READ

COM V

4

c

LCD display.

d

MEM key : Manual data memory control key.

e

LOCK key : Locks the test Insulation Resistance (MΩ).

a). Press and hold down TEST key, then press LOCK key, the

“ LOCK ” icon appears on the display.

b). In MΩ mode continuously applies the test voltage to the circuit to

be tested. The beeper sounds every 2 seconds to remind you
that you are in the LOCK mode.

c). Press Lock or TEST key again to exit the mode.

f

READ key: Manual memory data reading control key.

g

key: In Ω function, turns the test lead resistance

compensation ON.

VM

M

V

h

TEST key :

the
display indicates 0.0Ω.

icon appears on the display and the main

Touch the probe tips together, then press

key,

a). Used for MΩ test functions.

b). Press and hold TEST key until the main display reading is stable.

▼▲

i j

keys : In READ mode, select the memory data location for

direct reading the data from the display.

k

Rotary switch : To select a measurement function.

l

Input terminals.

5

Display :

MEM

READ

DC

V

M

M

c

Manual data memory and read location indicator.

d

Beeper symbol shows if beeper turned on in

e

High voltage warning symbol flashes, if voltage ≧ 30V is present on the

probes.

f

Resistance reading held from the last measurement in MΩ and

function.

g

Zero symbol is on if test leads are zeroed out.

h

Lock symbol is on if the TEST mode is locked in MΩ functions.

i

Low battery symbol.

j

Main display reading for all functions.

k

Analog bar graph displays resistance on a logarithmic scale and

voltage on a linear scale. The value always tracks the main display.

Ω

function.

6

4. BEFORE OPERATION

Warning

To avoid electrical shock remove test leads before opening case or

battery cover. Do not operate with battery cover open.

To avoid electrical shock when performing resistance tests, remove

all power from the circuit to be measured.

To avoid electrical shock, first connect the test leads to the meter

inputs before you make connection to the circuit under test.

To avoid electrical shock, do not touch test lead tips, test points or

terminals when pressing TEST.

4-1 How to connect test leads.

Ω

Connect the red test lead into the “ VΩ ” terminal and the black
lead into the “ COM ” terminal.

4-2 Battery Check & Replacement

1). If battery power is not sufficient, LCD will display “
Replacement of 6 pcs new batteries, type 1.5V size “AA” is required.

2). Use a screw drive to unscrew the screw secured on battery cover.
Take out the used batteries and replace 6 pcs new batteries.

3). Place back the battery cover and secure the screw.

4-3 Auto-Power-Off

1). The meter automatically turns off after 15 minutes of non-use.

2). To turn the meter back on, turn the rotary switch to OFF, then to
the desired function.

4-4 Test Leads Check

Set the range select switch to the “
crocodile clips with the test lead tips, Clip alligator clips with lead
other. The indicator should read <0.5Ω. When the leads are not

connected the display will read infinity indicated by “

will ensure that test leads are under working condition.

Ω

” range. Connect the

BT

－

－

”. This

”.

4-5 Manual Data Memory and Read Mode :

1). Clear the manual memorized data

c Set the function switch to OFF position to turn off the meter.

d Press and hold down "MEM" key, and turn on the meter.

When LCD shows "dEL" which means the manual memorized
data is erased.

2). Manual data memory

c Press "MEM" key each time, one set of reading to will be

stored to the memory. At this moment, LCD will show the
"MEM" mark and the memory address number. Total memory
size is 9 sets.

d When the memory is full, LCD will show " 9 " memory address

number.

3). Read Manual memory data

c Press "READ" key to enter READ mode, the LCD will show

"READ" mark and the memory address number.

d Press " " or " " key to select the desired memory address

number data for display.

e Press " READ " key again to exit this mode.

7

8

5. Ω RESISTANCE AND CONTINUITY MEASUREMENTS

1). Set the function switch to

2). Connect red test lead to “ VΩ ” terminal and black test lead to
“ COM ” terminal.

3). Connect the probe to the circuit to be measured. Measure
voltage first to ensure that no haszardous voltage is present, then
switch to ohms.

4). Read the resistance value from the display. If the resistance is
approximately 40Ω or less, the meter will beep.

Ω

position.

6. MΩ INSULATION RESISTANCE MEASUREMENTS

6-1 Measuring Insulation Resistance

Measuring insulation resistance requires the application of
potentially dangerous voltage to the circuit. This may include
exposed bonded metal work.

Before proceeding, ensure that the installation is correctly wired
and no personnel are endangered by any test.

1). Set the function switch to the desired MΩ test voltage position.

2). Connect red test lead to “ VΩ ” terminal and black test lead to
“ COM ” terminal.

3). The display will show “-----“ until the TEST button is pushed.

Press and hold the TEST key. The upper right display shows
the test voltage applied to the circuit under test. The main
display shows the resistance until a stable resistance reading is
displayed on the main display.

4). Keeping the probes on the test points when release the TEST key.

9

The upper right display shows the measured resistance reading
and the circuit now discharges through the meter, while the
main display reading shows the decreasing voltage, keep the
probe touched to test points until the circuit is completely
discharged and the main display shows “-----“.
The upper right display holds the resistance reading until a new
test is started or a different function is selected.

6-2 Using the LOCK Function to Measure Insulation Resistance

The LOCK function holds the test voltage on the probes. Use
LOCK function to make long duration measurements, don’t need to
push and hold the TEST key.

1). Press and hold the TEST key, then press the LOCK key to enter
LOCK mode. In this mode, a potentially dangerous voltage is
continuously applied to the probes.

In this mode, if the probes are disconnected from the circuit, the
meter cannot discharge any potentially dangerous capacitive
voltages left on the circuit.

Ensure that the circuit is de-energized before connecting the test
probes.

2). Press LOCK or TEST key to disable the Lock function.

10

7. POWER TOOLS AND SMALL APPLIANCES

This test would also apply to other similar equipment that has a line cord.
For double insulated power tools, one leads of megohmmeter to be
connected to the housing. The other leads would be connected to some
metal part of the tool (e.g. chuck, blade).

Note: The switch of the device must be in the “ON” position and the main

power should be disconnected.

MOTORS

AC-Disconnect the motor from the line by disconnecting the wires at the
motor terminals or by opening the main switch. If the main switch is
used and the motor also has a starter then the starter must be held, by
some means, in the “ON” position. In the latter case, the measured
resistance will include the resistance of the motor, wire and all other
components between the motor and the main switch. If a weakness is
indicated, the motor and other components should be checked
individually.
If the motor is disconnected at the motor terminals, connect one
megohmmeter lead to the grounded motor housing and the other lead to
one of the motor leads.

Disconnect the motor from the line. To test the brush rigging, field coils
and armature connect one megohmmeter lead to the grounded motor
housing and the other lead to the brush on the commutator.
If the resistance measurement indicates a weakness, raise the brushes
off the commutator and separately test the armature, field coils and
brush rigging by connecting one megohmmeter lead to each of them

individually, leaving the other connected to the grounded motor housing.
The above also applies to DC Generators.

11

CABLES

Disconnect the cable from power. Also disconnect opposite end to avoid
errors of any leakage from other equipment. Check each conductor to
ground and /or lead source by connecting one megohmmeter lead to a
ground and /or lead source and the other megohmmeter lead to each of the
conductors in turn. Check insulation resistance between conductors by
connecting megohmmeter leads to conductors in pairs.

8. FUSE CHECK & REPLACEMENT

8-1 Testing the Fuse

1). Set the function switch to LoΩ position.

2). Connect the test leads to the input terminals and short then together.

3). Press TEST key, the display should indicate approximately 0.5Ω, if the

display reads OL, replace the fuse as described next and test again.

12

8-2 Replace the Fuse

Warning

To avoid electric shock, personal injury or damage to the meter, use
only the specified fuse.

1). Set the function switch to OFF position.

2). Disconnect test leads from any power source.

3). Place the meter face down on a nonabrasive surface and loosen the
four screws.

4). Take off the bottom cover.

5). Remove the fuse, replace with a new fuse.

6). Place the bottom cover on and secure the four screws.

7). Test the fuse (refer 8-1 Testing the Fuse).

9. BATTERY REPLACEMENT

1). Set the function switch to OFF position.

2). Disconnect test leads from any power source.

3). Place the meter face down on a nonabrasive surface and loosen the
two screws.

4). Take off the battery cover.

5). Remove the battery, replace with six new batteries.

6). Place the battery cover on and secure the two screws.

10. MAINTENANCE & CLEANING

Maintenance & Clearing :

1). Repairs or servicing not covered in this manual should only be

performed by qualified personnel.

2). Periodically wipe the case with a dry cloth.

Do not use abrasives or solvents on this instrument.

13

WARRANTY

Congratulations! Your new instrument has been quality
crafted according to quality standards and contains quality
components and workmanship. It has been inspected for
proper operation of all of its functions and tested by qualified
factory technicians according to the long-established
standards of our company.

Your instrument has a limited warranty against defective
materials and/or workmanship for one year from the date of
purchase provided that, in the opinion of the factory, the
instrument has not been tampered with or taken apart.

Should your instrument fail due to defective materials,
and/or workmanship during this one-year period, a no
charge repair or replacement will be made to the
original purchaser. Please have your dated bill of sale,
which must identify the instrument model number and
serial number and call the number listed below:

Repair Department
ATP – Amprobe, TIF, Promax
Miramar, FL
Phone: [phone]

800-327-5060

Fax: [phone]
Website: www.Amprobe.com

Please obtain an RMA number before returning product
for repair.

Outside the U.S.A. the local representative will assist you.
Above limited warranty covers repair and replacement of
instrument only and no other obligation is stated or implied.

Miramar, FL

Phone: [phone]

Fax: [phone]

www.Amprobe.com

Sep-2003