CEM DT-5500 User manual

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DIGITAL INSULATION TESTER
INSTRUCTION MANUAL
SAFETY INFORMATION
Read the following safety information carefully before
attempting to operate or service the meter.
To avoid damages to the instrument do not apply the
signals which exceed the maximum limits shown in the
technical specifications tables.
Do not use the meter or test leads if they look damaged.
Use extreme caution when working around bare
conductors or bus bars.
Accidental contact with the conductor could result in
electric shock.
Use the meter only as specified in this manual;
otherwise, the protection provided by the meter may be
impaired.
Read the operating instructions before use and follow
all safety Information.
Caution when working with voltages above 60V DC or
30V AC RMS. Such voltages pose a shock hazard.
Before taking resistance measurements or testing
acoustic continuity, disconnect circuit from main power
supply and all loads from the circuit.

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Safety symbols:
Caution refer to this manual before using the meter.
Dangerous voltages.
Meter is protected throughout by double insulation or
reinforced insulation.
When servicing, use only specified replacement parts.
CE Comply with EN-61010-1
1. SPECIFICATIONS
1-1 General Information
Environment conditions:
①Installation Categories II
②Pollution Degree 2
③Altitude up to 2000 meters
④Indoor use only
⑤Relatively humidity 80% max.
⑥Operation Ambient 0~40ºC
Maintenance & Clearing:
①Repairs or servicing not covered in this manual should
only be performed by qualified personnel.
②Periodically wipe the case with a dry cloth. Do not use
abrasives or solvents on this instruments.
Display: LargeLCDwithdualdisplay
Measurement Range: 200Ω, 200kΩ, 200MΩ/250V,
200MΩ/500V, 2000MΩ/1000V,
750V/ACV, 1000V/DCV.
Sampling Rate: 2.5 times per second.
Zero Adjustment: Automatic adjustment.
Over Range Indicator: Number 1 of highest digit is
displayed.
Low Battery Indication: The is displayed when the
battery Voltage drop below the
operating voltage.
Operating Temperature: 0ºC to 40ºC (32ºF to 104ºF) and
Humidity below 80% RH
Storage Temperature: -10ºC to 60ºC (14ºF to 140ºF) and
Humidity below 70% RH
Power source: DC9V (6x1.5V Size “AA” battery or Equivalent)
Dimensions: 200(L) x 92(W) x 50(H) mm
Weight: Approx 700g include battery
Accessories: Test leads, 6pcs battery, Carrying case, manual.

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1-2 Electrical Specifications
Accuracies are specified in the way:
±(…% of reading +…digits) at 23ºC±5ºC,below 80% RH.
OHMS
Range
Resolution
Accuracy
Max. open
Circuit
Voltage
Overload
Protection
200Ω
0.1Ω
+(1%+2)
4.5V
250Vrms
200kΩ
0.1kΩ
3.0V
Continuity Beeper
Range
Resolution
Operation
Resistance
Max.open
Circuit
Voltage
Overload
Protection
•)))
0.1Ω
Resistance≤40Ω
4.5V
250Vrms
Short circuit current
≤200mA
DC Voltage
Range
Resolution
Accuracy
Input
Impedance
Overload
Protection
1000V
1V
+(0.8%+3)
10MΩ
1000Vrms
AC Voltage (40Hz~400Hz)
Range
Resolution
Accuracy
Input
Impedance
Overload
Protection
750V
1V
+(1.2%+10)
10MΩ
750Vrms
Meg OHMS
Range
Resolution
Accuracy
Terminal Voltage
200MΩ/250V
0.1MΩ
+(3%+5)
250V+10%~-0%
200MΩ/500V
0.1MΩ
500V+10%~-0%
0~1000MΩ/1000V
1MΩ
1000V+10%~-0%
1000~2000MΩ
/1000V
+(5%+5)
Range
Test Current
Short circuit current
200MΩ/250V
1mA
250KΩ(load)
≤1mA
200MΩ/500V
500KΩ(load)
0~1000MΩ
/1000V
1MΩ
1000~2000MΩ
/1000V

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2. PARTS & CONTROLS
①Digital Display
②Data Hold Button
③Lock Button
④Backlight Button
⑤Test Button
⑥Rotary Function switch
⑦VΩJack
⑧COM input jack
⑨Pothook
⑩Battery Cover
3. BATTERY REPLACEMENT
3-1 How to connect test leads.
a). On MΩRange: Connect the red test lead into the “VΩ”
terminal and the black lead into the “COM” terminal.
b) On 200ΩandACV Range: Connect the red test lead into
the “VΩ” terminal and the black lead into terminal “COM”
3-2 Battery Check-UP & Replacement
a) As battery power is not sufficient. LCD will display .
Replacement of 6 pcs new batteries, type 1.5V size “AA”
is Required.
b). Place back the battery cover and four the screws.
3-3 Test leads check
Set the range select switch to the 200Ωrange. With the tip
and alligator clip of the test leads connected. The indicator
should read 00.0Ω. When the leads are not connected the
display will read infinity indicated by “1”. This will ensure that
test lead are under working condition.
4. INSULATION RESISTANCE
MEASUREMENTS
a). Measurements at 200MΩ/250V This is the voltage used
for the majority of insulation resistance tests on normal
installation requirement. To measure insulation resistance,
press the test button to power on the tester. The LCD will
displayed the insulation resistance. Section VII indicated

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that subdivision of large installations might be necessary
because of the large number of parallel insulation
resistance. In such a case, an installation may be divided
into sections, each being separately tested. Each section
must have not less than fifty outlets, an outlet being a
switch, socket, lighting point etc. A switched socket
counts as one outlet. The minimum acceptable insulation
resistance is 1MΩ. For a large installation, the
capacitance of the insulation will be high, and it will take
longer for it to become charged by the direct testing
voltage. Care must be taken not to take a reading until
there is a steady reading, indicating that the charging
process is complete.
Note: The charge stored in the insulation will be discharged
automatically when the test button is released. Be
careful not to turn the range switch knob whilst the test
button is pressed, or the instrument will be damaged.
b). Measurements at 2000MΩ/1000V
Some specifications require testing at 1000V. This voltage
must also be selected where the supply voltage of the
installation is between 500V and 1000V. First, set the
range switch to 1000V and then proceed as indicated in a
above for 500V testing. The above note also applies to
testing at 1000V. In addition the following applies.
Note: Make sure that the circuit under does not include
components Which will be damaged by the 1000V
applied. Many normal components of an installation are
likely to be damaged if tested at 1000V. Examples are
power factor correction capacitors, low voltage mineral
insulated cables, electronic light dimmers, electronic
ballasts and starters for fluorescent lamps etc…
c). Lock power on Feature
For hands free operation a lock power on feature is
incorporated on the press to test button. Set LOCK button
to lock test voltage, Pressing it again will tester off.
5. LOW RESISTANCE (CONTINUITY)
MEASUREMENTS
a). Set the range switch to 200Ω∙))) Position
b). Connect the red test lead to the V Ωterminal and black to
the COM terminal.
c). Connect the tips of the test leads to both ends of the
circuit under test. read resistance in Ωon the LCD.
d). When the impedance on circuit is below approximately
40Ω.It will indicate by a continuous beeper.
6. AC/DC VOLTAGE MEASUREMENTS
a). Set the range switch toACV or DCV position
b). Connect red test lead to “V Ω” terminal and black test lead
to terminal “COM”.
c). Connect test prods of test leads IN PARALLEL to the
circuit being measured.
d). Read the voltage value on LCD.

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7. POWER TOOLS AND AMALL
APPLIANCES
This test would also apply to other similar equipment that has
a line cord. For double insulated power tools, the
megohmmeter lead shown connected to the housing would
be connected to some metal part lf 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 in dicated, 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. DC-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
Gemerators.

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