IM 2404-10E <2>
2. NAMES AND FUNCTIONS OF COMPONENTS
(4)
(2)
(1)
(6)
(5)
(3)
Figure 2-1
(1) Function Select Switch :
Insulation and AC voltage measurements (M
Ω
and V) and resistance Test (
Ω
) can be selected
with this switch. (except Models 240415, 240416)
(2) LINE Terminal:
To measure Insulation resistance, AC voltage and resistance use this LINE terminal and the
EARTH terminal (3) below.
(3) EARTH (ground) Terminal
(4) GUARD Terminal
(5) Crank
(6) Carrying Handle
3. OPERATION
3.1. AC Voltage Measurement
(l) Power line AC voltages can be measured using this tester. Always prior to an insulation
resistance measurement, use the tester to check whether the object to be measured is live or not.
(2) Connect measuring lead wires to the LINE and EARTH terminals. Use optional accessory
B9634FA measuring leadwires or equivalent high insulation resistance leadwires.
(3) Place the instrument on a fairly level surface with the crank facing you. Turn the carrying
handle down.
(4) Set the function select switch to V. Prior to connecting an object for an AC voltage
measurement, short-circuit the tester LINE and EARTH lead wires. Turn the crank to check to
see that the indicator shows zero ohms. This confirms that the tester is operating normally.
(5) To make a voltage measurement touch the LINE and EARTH lead wires to the line to be
measured and read the indication on the “AC V” scale as you would read in ordinary voltmeter.
During voltage measurement, do not turn the crank.
3.2 Insulation Resistance Measurement
(1) Read the NOTE below, then connect the object to be measured between the LINE and EARTH
terminals. Set the function select switch to M
Ω
.
(2) Turn the crank at a speed of more than 120 rpm to obtain a constant voltage output. The pointer
will indicate the measured insulation resistance value.
*
Crank rotation may be either clockwise or counterclockwise.
(3) While turning the crank, read the pointer indication.
CAUTION
•When one side of the measured circuit is grounded, connect the earth side to the EARTH
terminal (positive side) of the tester. Normally, this connection gives smaller (conservative)
values of insulation resistance, to be on the safe side. In this case, the lead-wires connected to
the LINE terminal (negative side) should be kept always from earth and other objects.
• When the measured circuit is not grounded, it may be connected to either LINE or EARTH
terminal.
• The GUARD terminal is used only when volume resistance is to be measured without being
influenced by surface leakage resistance. For example, when the insulation test is conducted on
a cable such as shown in Figure 3-1, wind a bare wire around the insulating material and
connect this wire to the GUARD terminal. In this arrangement, the leakage current flowing on
the surface of the insulating material will not pass through the indicator. Thus, only the volume
resistance is measured.
GUARD
LINE
EARTH
Insulating Material
Core Wire
Dead-sheathed Wire
Insulation Tester Model 2404
Figure 3-1 Connections
3.3 Low Resistance Measurement
Set the function select switch to
Ω
. Connect the object at be measured between the LINE and
EARTH leadwires. Turn the Crank at a speed of more than 120 rpm and read the indication on
the “
Ω
” scale. Low resistance measurement cannot be made using the Models 240415 (1000 V/
2000 M
Ω
) and 240416 (2000 V/5000 M
Ω
) insulation testers.
CAUTION
• Be sure not to apply a voltage between the terminals during low resistance measurement.
• If power line AC voltage is applied to the instrument in error while on the low resistance
range, the instrument is protected by an internal fuse. If the fuse is blown, replace it
according of the procedure as described in paragraph 4.2. Insulation resistance and AC
voltage can be measured normally even when the fuse is blown.
• If the fuse is blown, the pointer points to the “*” mark during low resistance measurement.
(See Figure 3-2)
• The 1k mark on the
Ω
scale is not accurate and may be considered as being “off scale”. Note
that there is no resistance scale mark for Rx =
∞
(when test probes are not connected to
anything).
Figure. 3-2
4. MAINTENANCE
4.1 Storage
When storing the Insulation Tester, avoid area which is:
• Very humid.
• Subject to direct sunlight.
• Near high temperature heat sources.
• Subject to strong vibration.
• Very dusty, or contains corrosive gases.
4.2 Fuse Replacement
If the fuse is blown during the low resistance measurement, replace the fuse as follows. Remove
two case fixing screws on the bottom of the instrument. Then the instrument can be
disassembled into two parts as shown in Figure 4-1. Replace the fuse on the printed circuit
board with a spare fuse (0.1 A). Two spare fuses are installed inside the instrument case.
Figure 4-1 Fuse Replacement
■
Notice Regarding This Manual
1. The contents of this manual are subject to change without prior notice.
2. If any questions arise or errors are found, or if any information is missing from this manual, please
inform Yokogawa.
3. Yokogawa is by no means liable for damage resulting from the misuse of this product by the user.
4. This manual is intended to explain the functions of this product Yokogawa does not warrant that
the functions will suit a particular purpose of the user.
IM3E-2006.2
Yokogawa Meters & Instruments Corporation
International Sales Dept.
Tachihi Bld. No.2, 6-1-3, Sakaecho, Tachikawa-shi,Tokyo 190-8586 Japan
Phone: 81-42-534-1413, Facsimile: 81-42-534-1426
YOKOGAWA CORPORATION OF AMERICA (U.S.A.)
Phone: 1-770-253-7000 Facsimile: 1-770-251-2088
YOKOGAWA EUROPE B. V. (THE NETHERLANDS)
Phone: 31-334-64-1611 Facsimile: 31-334-64-1610
YOKOGAWA ENGINEERING ASIA PTE. LTD. (SINGAPORE)
Phone: 65-6241-9933 Facsimile: 65-6241-2606
YOKOGAWA AMERICA DO SUL S. A. (BRAZIL)
Phone: 55-11-5681-2400 Facsimile: 55-11-5681-1274
YOKOGAWA MEASURING INSTRUMENTS KOREA CORPORATION (KOREA)
Phone: 82-2-551-0660 to -0664 Facsimile: 82-2-551-0665
YOKOGAWA AUSTRALIA PTY. LTD. (AUSTRALIA)
Phone: 61-2-9805-0699 Facsimile: 61-2-9888-1844
YOKOGAWA INDIA LTD. (INDIA)
Phone: 91-80-4158-6000 Facsimile: 91-80-2852-1441
YOKOGAWA SHANGHAI TRADING CO., LTD. (CHINA)
Phone: 86-21-6880-8107 Facsimile: 86-21-6880-4987
YOKOGAWA MIDDLE EAST E. C. (BAHRAIN)
Phone: 973-358100 Facsimile: 973-336100
LTD. YOKOGAWA ELECTRIC (RUSSIAN FEDERATION)
Phone: 7-095-737-7868 Facsimile: 7-095-737-7869
