The following general safety precautions must be observed
during all phases of operation, service and repair of this
instrument. Failure to comply with these precautions or with
specific WARNINGS given elsewhere in this manual violates
the safety standards of the design, manufacture and intended
use of the instrument.
YOKOGAWA assumes no liability for the customer’s failure to
comply with these requirements.
This manual is part of the product and contains important
information. Store this manual in a safe place close to the
instrument so that you can refer to it immediately.
Keep this manual until you dispose of the instrument.
The 2041 instruments are shipped only after stringent inhouse inspection. Should the instrument suffer damage that
is attributable to improper manufacture or an accident during
transport, contact the sales representative from which you
purchased the product or your nearest YOKOGAWA sales
ofce.
All products of YOKOGAWA are guaranteed for a period of one
(1) year from the date of delivery.
YOKOGAWA will repair the product in question, free of charge,
if the product fails during the guarantee period for reasons that
The
electrodynamic type wattmeter that is used to measure DC and AC electric
power in laboratories and factories.
The single-phase wattmeter (Model 2041 01*, 2041 02 and 2041 03) can
measure DC power with a frequency of 25 to 1000 Hz.
The low-power-factor wattmeters (Model 2041 11* to 2041 22*) can be
used for carrying out an Epstein frame test on core loss or for measuring
either power of a low power factor or low levels of electric power.
The low-power-factor single-phase wattmeter can measure DC power with
a frequency of 25 to 500 Hz.
* The 2041 01(Single-phase wattmeter) has been discontinued.
The Single-phase low-power wattmeters (2041 11 to 2041 22)
Portable Single-phase Wattmeter is a taut-band suspension,
These are used for the voltage connection.
The common terminal is marked with the voltage polarity “±”, and
the two other terminals are marked with their respective voltage
ratings.
Current Terminals:
One of the terminals is marked with “±” to show the polarity
relation to the voltage coil, and the two alternative current
terminals are marked with their respective current ratings.
Table of Range-multiplier Constants:
The table is located on the side of the instrument case, and the
actual power value is obtained by multiplying the constant listed in
the table by the indication value on the scale.
Refer to the operational procedure for more information.
1. Do not use these instruments in a location exposed to direct sunlight, an
external magnetic eld or mechanical vibration or in a high-temperature
highly humid environment.
2. Place the instrument on a fairly level surface.
A horizontal position will give the highest accuracy.
3. When using a number of these instruments in an array, keep them as far
away from each other as possible.
4. Before wiring any of these instruments, carefully check the measuring
ranges and polarities. When wiring, securely fasten the terminals.
When a large current needs to be measured, use wire that is both thick
enough and has sufcient current-carrying capacity.
5. Before measurement, check that the pointer coincides exactly with the
zero scale point. If it does not turn the zero adjust screw provided on
the meter cover until the pointer meets the zero scale point.
Position your eye so that the mirror image of the pointer coincides with
the actual pointer. However, if the pointer is off from the zero scale
point because the pointer is bent, do not adjust using the zero adjust
screw because this will lead to errors.
6. Be careful not to apply an unreasonably large current or high voltage to
the instrument.
7. For the optimum instrument accuracy, select a measuring range such
that the indication may be read in the top half of the scale.
8. Try not to apply too much force when wiping the glass window surface
of the instrument during measurement. Doing so, may result in a
deviation in the indication due to static electricity.
This is especially true when the instrument is used in a dry season.
If the surface is dirty, clean it gently with a dry soft cloth.
5. Three-phase AC power measurement (by two sets of wattmeters)
Three-phase power measurement is made by connecting two sets of singlephase wattmeters as shown in Fig. 2-6. The power is indicated by the
algebraic sum of the indications of the two wattmeters.
When the power factor of the circuit to be measured id greater than 50%,
both of the wattmeters connected as shown in Fig. 2-6 indicate “positive”
values.
The measured three-phase power is the algebraic sum of the indications
on these two meters. When the power factor of the circuit to be measured
is less than 50%, the pointer on one of the two wattmeters will deflect
backward off the scale. In this case, reverse the voltage connections of
the meter whose pointer deects backward, so that the meter indicates a
“positive” value on the scale. Subtract this value from the positive value
on the other meter.
1. For power measurement, select a voltage range which is likely to be
close to the voltage of the circuit to be measured. If the load current is
unknown, rst select the largest current terminal for connection, and
then turn on the power switch.
Both voltage and current ranges are changed by selecting terminals.
The ratio of the voltage ranges is 2:1.
The ratio of the current ranges is 5:1.
2. Be sure not to open the secondary circuit of the CT when changing
the measuring range. If the CT is provided with a switch to short the
secondary circuit, close the circuit using the switch before changing the
measuring range. If such a switch is not provided, you can either switch
off the power source before proceeding with the change or you can
follow the alternative wiring method for changing the range.
In this method, you short the CT current terminal currently connected
to the wattmeter with the CT current terminal to be used for the new
measuring range, and then connect that new current terminal to the
wattmeter. After doing this, you can then disconnect the originally
connected CT current terminal that will no longer be used.
When using the low-power-factor wattmeter to measure low power levels
of AC-line frequency and a power factor of around 1.0, it is important to
determine the current or voltage range carefully. If you select a smaller
range than the voltage or current of the circuit to be measured, the
wattmeter pointer will go overscale. Estimate the approximate value of the
power to be measured, and then select a suitable rated power range (equal
to or higher than the estimated value).
Remember the instrument is a highly sensitive meter – ve times more
sensitive than an ordinary wattmeter (whose power factor =1). Therefore
at the rated power factor of 0.2, the rated voltage and rated current when
the pointer indicates full scale, will be one fth of those measured at a
power factor of 1.0.
* Single-phase low-power wattmeters (Model 2041 11 to 2041 22)
If the circuit whose electric power is measured by the
low-power-factor wattmeter includes a CT or VT, then a
phase angle error affects the wattmeter indication such that it
gives an inaccurate power measurement.
The table of range multipliers shown on the label on the side of the
wattmeter is used to convert the value read on the 120-division scale to a
power value. In other words, the power can be calculated from equation 1.
The range multipliers depend on the voltage and current range settings and
are calculated from equation 2.
Voltage range
Current range
1 A
5 A
(2) 単相低力率電力計の場合 *
乗数は,式 3 で与えられますが使用電圧,電流レンジに応じて表から
引いてください。
Voltage range
Current range
1 A
* 単相低力率電力計 (2041 11 〜 2041 22)は,受注停止製品です。
IM 2041-01
5 A
Multiplier constant
120 V
1
5
240 V
2
10
Multiplier constant
120 V
0.2
1
240 V
0.4
2
— 10 —
rated current (A) × rated voltage (V) × rated power factor (1.0)
=
…
Example:
Instruments with a rated current of either 1 A or 5 A and
a rated voltage of 120 V or 240 V.
(2) Single-phase low-power wattmeter*
The range multipliers depend on the voltage and current range settings and
are calculated from equation 3.
rated current (A) × rated voltage (V) × rated power factor (0.2)
=
…
Example:
Instruments with a rated current of either 1 A or 5 A and
a rated voltage of 120 V or 240 V.
* Single-phase low-power wattmeters (Model 2041 11 to 2041 22)
have been discontinued.
4. 自己消費電力の補償
Fig. 3-2
電源
負荷
電圧計
電源
Power Source
負荷
計器の指示は,負荷の電力と計器の負荷側に結線されたコイル(電流
コイルまたは電圧コイル)の消費電力との和となりますので,負荷の
電力を精密に測定したい場合や小さい電力計(500 W 以下)の場合,
計器自身の消費電力を計器の読みから差引かなければなりません。
The indication on the wattmeter is the sum of the load power and the
power consumption of the coil (current or voltage coil) connected to the
load side of the wattmeter. Therefore, to measure load power accurately
using low rated-power wattmeters (less than 500 W such as the low-power
wattmeter), the power consumption of the meter itself must be subtracted
from the meter reading.
1. Correction when the voltage coil is connected to the load side
• If the power source impedance is low and the voltage uctuation is small
or the load power is comparatively small, the connections are as shown
in Fig. 3-1, and the power loss of the voltage coil is almost the same as
the indication when the load is disconnected.
• If the power source impedance is high or the load power is large,
the connections are as shown in Fig. 3-2, and the load power can be
calculated from the formula shown using a voltmeter with a given
internal impedance.
MC
Load
±
±
電源
Power
Source
±
FC
MC: 電圧コイル Voltage Coil
FC: 電流コイル Current Coil
Fig. 3-1
±
A
V
負荷
Load
— 11 —
Power Source
±
±
Voltmeter
r'
r
Load
1
P = W – V
P: 負荷電力
Load power
W: 電力計の指示電力
Wattmeter indication
V: 電圧計の指示電圧
Voltmeter indication
r: 電力計の電圧回路抵抗
Wattmeter Voltage circuit
impedance
r': 電圧計の内部抵抗
Voltmeter internal impedance
2
( + )
r
1
r'
IM 2041-01
(2) 電流コイルが負荷側に結線された場合の補償
Fig. 3-3
Power Source
Load
PP
Fig. 3-3 のように電流コイルを電圧コイルより負荷側に結線した場合,
電圧結線の接続点 P を Q 点に変えると電力計の指示は電流コイルの
損失を示します。この値を始めの指示値から引けば真の負荷電力を
求めることができます。
2. Correction when the current coil is connected to the load side
If the current coil is connected to the load side through the voltage coil as
shown in Fig. 3-3 and the voltage connection is moved from P to Q, the
wattmeter will indicate the power loss of the current coil. Subtract this
value from the reading on the scale to obtain the true load power.
1. To ensure good measurements, keep the instrument free of dust,
moisture, and away from direct sunlight.
2. If an overload or excessive shock causes the accuracy of the instrument
to become doubtful, check several scale points and compare these
readings with an instrument which has been properly calibrated.
If the accuracy of the instrument is found to be different from its rating,
readjust the instrument.
NOTE
If any troubles occur in the instrument, contact your nearest
YOKOGAWA Sales office or sales agent.
※ Total volt-ampere loss of the 2041 = volt-ampere loss of voltage range +
volt-ampere loss of current range.
Power Rating
120 V
240 V
24 W
240 W
120 W
240 W
120 W
1.2 kW
600 W
1.2 kW
600 W
3 kW
48 W
6 kW
Approx.
Internal
Volt-Ampere
Impedance
12000 Ω
24000 Ω
16.35 Ω
0.56 Ω
0.93 Ω
0.034 Ω
0.064 Ω
0.0027 Ω
* 受注停止製品
* Discontinued product
Approx.
Loss
1.2 VA
2.4 VA
0.66 VA
0.56 VA
0.93 VA
0.84 VA
1.72 VA
1.69 VA
定格
Rating (Range)
Rated
Current
0.2/1 A
1/5 A
5/25 A
Rated
Voltage
0.2 A
1 A
1 A
5 A
5 A
25 A
Model
2041 11*
2041 12*
2041 13*
定格
Rating (Range)
Rated
Rated
Voltage
Model
Current
0.2/1 A
1/5 A
0.2 A
1 A
1 A
2041 21*
2041 22*
5 A
形名
形名
Power Rating
120 V
240 V
9.6 W
4.8 W
24 W
24 W
240 W
120 W
240 W
120 W
1.2 kW
600 W
Power Rating
30 V
2.4 W
1.2 W
6 W
6 W
30 W
48 W
48 W
60 V
12 W
12 W
60 W
Approx.
Internal
Impedance
6000 Ω
12000 Ω
31.3 Ω
1.09 Ω
1.70 Ω
0.06 Ω
0.105 Ω
0.004 Ω
Approx.
Internal
Impedance
1500 Ω
3000 Ω
31.3 Ω
1.09 Ω
1.70 Ω
0.06 Ω
Approx.
Volt-Ampere
Loss
2.4 VA
4.8 VA
1.25 VA
1.09 VA
1.70 VA
1.50 VA
2.62 VA
2.50 VA
Approx.
Volt-Ampere
Loss
0.6 VA
1.2 VA
1.25 VA
1.09 VA
1.70 VA
1.50 VA
— 15 —
IM 2041-01
<アクセサリ Accessories>
計器用変流器:
0.2級
Current Transformer: 0.2%
2262 00 *
計器用変圧器:
Voltage Transformer: 0.2%
measuring ranges, and with through-hole terminals for the 250 A, 300 A, 500 A,
注 1. 最高回路電圧
2.
3.
4.
* 受注停止製品
* Discontinued product
形名
Model
2241
2242
2244
コード
Code
00
00
00
2243 00 *
2241: 3450 V
2242: 6900 V
2244 (2243*): 250 V
2241, 2242: 10~100 Aの測定範囲は端子式
2243*: 0.1級
2244:電流測定専用,電力測定不可
0.2級
形名
Model
2261
2261 02 *
2261 03 *
コード
Code
01110 V
一次
Primary
10/15/30/50/100/250/300/500/750/1500 A
10/15/30/50/100/250/300/500/750/1500 A
500 A (500 AT)
0.5/0.75/1/1.5/2/3/5/7.5/10/15/20/30/50/75/100 A
Note 1: The maximum line voltages are as follows.
2241: 3450 V
2242: 6900 V
2244 (2243*): 250 V
Note 2: The instruments also have the following characteristics.
250~1500 Aの測定範囲は貫通式
2241 and 2242: Equipped with screw terminals for the 10 A, 15 A, 30 A, 50 A and 100 A
Note 3: 2243*: Class 0.1 instrument
Note 4: 2244:For current measurements only. Cannot be used for power measurements.
一次
Primary
220/440/2200/3300 V
15/30/50/75 V
100/200/300/500 V
3300/6600 V
二次
Secondary
5 A
5 A
5 A
5 A
750 A and 1500 A measuring ranges.
二次
Secondary
定格負担
Burden
15 VA
15 VA
15 VA
15 VA
定格負担
Burden
15 VA
150 V
150 V
110 V
15 VA
15 VA
IM 2041-01
— 16 —
Printed in China
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