Store this manual in an easily accessible place
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User's
Manual
2nd Edition: October 2017 (YMI)
All Rights Reserved. Copyright ©
2015, Yokogawa Meters & Instruments Corporation,
2017, Yokogawa Test & Measurement Corporation
A3
Printed in China
9. Display Functions
Lit when the measured insulation
resistance is being held.
Flashes when the battery voltage is low.
Lit when the rating setting is
1000 V/2000 MΩ.
Lit when the rating setting is
500 V/2000 MΩ
Lit when the rating setting is
250 V/200 MΩ.
Lit when the rating setting is
125 V/200 MΩ.
Indicates overrange (OL).
Indicates the extension bar graph.
Change toward smaller values
Change toward larger values
Stable
Sub-display
Indicates:
• Comparator setting value or
the storage number; or
• The storage number for memory.
Indicates the unit for
insulation resistance for comparator.
Lit when:
• Pressing the MEAS key in
insulation resistance measurement; and
• Residual electrical charges are present
during discharging.
Lit when the comparator is activated.
Lit when the measured
insulation resistance is lower than
the comparator setting value.
Lit when the memory feature is in use.
Indicates the unit for
AC voltage measurement.
Indicates the unit for insulation resistances.
Indicates the unit for
conductor resistance measurement.
Indicates the continuity mark,
which is lit when the measured
insulation resistance is lower than 40 Ω.
The extension bar graph shows how
the measured value is changing
(trend) as follows:
Note that the number of marks means
the degree of change.
■ Overrange Display Functions
OL Display
The tester displays the OL mark when the measured resistance exceeds
the following values.
Insulation resistance measurement:
For 1000 V and 500 V ratings: 2000 MΩ
For 250 V and 125 V ratings: 200 MΩ
Conductor resistance measurement: 400 Ω
Display
The tester displays the mark when the internal calculation exceeds
the following values.
Insulation resistance measurement:
For 1000 V and 500 V ratings: approx. 4000 MΩ
For 250 V and 125 V ratings: approx. 400 MΩ
Change to Upper/Lower Ranges
• To upper range
When the digital reading exceeds 4000,
the measuring range changes to the next upper range.
• To lower range
When the digital reading falls below 360,
the measuring range changes to the next lower range.
Lower Resolution Display
If the digits below the decimal point are not stable,
they can be automatically omitted to limit the resolution.
10. Before Measurement
1. Safety
• Read the handling precautions in this manual carefully.
• Make sure it is safe before starting measurement.
2. Battery Voltage Verification
• Make sure that the battery voltages are within the valid ratings
(i.e. the
mark is not flashing).
• If the batteries are low, replace them as specified in the battery replacement
section of this manual.
NOTE
As the
mark indication depends on the load (current consumption),
check that the
mark does not appear for the largest load
when short-circuiting the earth probe and the line probe (0 MΩ).
3. Connecting the Probes
WARNING
• Remove the probes from the measured object before attaching/detaching
the probes to/from the tester.
• Make sure the MEAS key is off when attaching/detaching the probes to/from the tester.
• Plug the earth probe into the earth terminal.
• Plug the line probe into the line terminal.
4. Function Switch Verification
Be sure to confirm that the function switch is set to the desired rating.
5. 1000-V Rating
When measuring with the 1000-V rating,
see section 14.1, “Double-action1000-V Function”.
11. Measuring the Insulation Resistance
11.1 Before Connecting the Probes
WARNING
• Turn off the power to the measured object before connecting or
measuring insulation resistance.
• Electrical charges may be present in the cables attached to or metal of
the electrical equipment being tested. Verify that the equipment is free from
electrical charges before connecting the testing terminals.
• Be sure to confirm that the function switch is set to the desired rating.
ON
OFF
125 V/200 MΩ
250 V/200 MΩ
500 V/2000 MΩ
1000 V/2000 MΩ
Measurement wiring
Insulation resistance ratings:
Power supply side
(primary)
Load side
(secondary)
Set the switch to OFF
Line probe
Earth probe
11.2. Setting the Function Switch
Turn the function switch to the desired measurement rating position.
The initial display is “---- MΩ”.
11.3 Connecting the Earth Probe
• If the measured object is grounded, connect the earth probe clip to
the measured object’s ground line.
• If the measured object is not grounded, this process may be omitted.
11.4 Connecting the Line Probe
Bring the line probe into contact with the measured object, and then
press the
key. The display indicates the insulation resistance of
the measured object.
NOTE
During measurement, exercise care to prevent the leadwire of the line probe from
coming into contact with the ground, floor or any other object.
Not observing this precaution may result in a failure to measure the correct
insulation resistance.
11.5 After Measurement
WARNING
• Immediately after measurement, electrical charges resulting from the applied testing
voltage may remain present in the probes or measured object.
• The tester, therefore, is designed to automatically begin discharging electricity upon
completion of measurement.
Verify that the ALARM LED turns off when discharging is complete.
12. Measuring AC Voltages
WARNING
• Do not press the MEAS key while measuring AC voltages.
• Voltage that exceeds the specified limit (600 V) must not be applied to terminals.
Doing so causes all digits of the measuredvoltage to flash and the buzzer to beep.
12.1 Setting the Function Switch
Turn the function switch to an AC voltage
measurement (
V) position.
12.2 Connecting the Earth Probe
• If the measured object is grounded, connect the earth
probe clip to the measuredobject’s ground line.
• If the measured object is not grounded,
this process may be omitted.
12.3 Connecting the Line Probe
Bring the line probe into contact with the measured object.
The display indicates the AC voltage of measured object.
Model MY40
Insulation Resistance Tester
[ Operation Manual ]
This manual describes the specifications and handling precautions of
the insulation resistans tester.
Before using this product, thoroughly read this manual to understand how to use it properly.
IM MY40-E:
Safety precautions, components and specifications etc.
IM MY40-02EN: Operation manual (this manual)
Contact information of Yokogawa offices worldwide is provided on the following sheet.
PIM 113-01Z2: Inquiries List of worldwide contacts
IM MY40-02EN
2nd Edition: Oct. 2017 (YMI)
