Some standard content:
Machinery Industry Standards of the People's Republic of China
Centrifugal Stove Blower
Subject Content and Scope of Application
This standard specifies the performance requirements and test methods for centrifugal stove blowers. JB 5881-91
replaces JB2575-79
JB2576-79
This standard is applicable to single-phase and three-phase centrifugal stove blowers for household and similar purposes under general environmental conditions ( Hereinafter referred to as hair dryer). This standard does not apply to hair dryers used under other special conditions. Reference standards
2
GB 4706. 1
GB4214
GB2828
GB2829
GB 191
GB1236|| tt || JB3189 | | tt | | JB5880 | ||Batch-by-batch inspection, counting, sampling procedures and sampling tables, periodic inspection, counting, sampling procedures and sampling tables, packaging, storage and transportation icons
Ventictor aerodynamic performance test method
Daily appliance product model||tt ||Safety requirements for centrifugal stove hair dryers
General rules for packaging of household appliances
3.1 Hair dryers are classified according to the single-phase or three-phase closed asynchronous motor they are equipped with, and the specifications are divided according to the inner diameter of the air outlet. 3.1.1 Capacitor-operated single-phase AC hair dryers are represented by CZR. 3.1.2 Other types of single-phase AC hair dryers are represented by CZQ. 3.1.3 Three-phase AC hair dryer is represented by CZT. 3.1.4 The hair dryer is a centrifugal AC hair dryer. From the inlet direction, it is divided into two types: left-hand and right-hand, represented by KZ and LY respectively. Its basic parameters and dimensions should comply with the provisions of Table 1. Table 1
rated voltage
rated frequency
gauge
grid
recommended impeller diameter
rated voltage
rated color Rate
Gauge
Grid
Recommended impeller diameter
V
Hz
mm
V
Hz | | tt | tt||105
330
45
150
120
370
220
50||tt| |60
200
135
400
380
50
75
250
75
250
380
50
90
290
1992-1001 implementation
3.2 product code||tt ||4 Technical requirements
4.1 Usage environment
4.1.1 The ambient air temperature does not exceed +50℃; 4.1.2 The altitude does not exceed 1000m;
JB 5881-91||tt ||Specification code (according to Table 1)
Type code, (centrifugal left/right-hand) according to Article 3.1.4 Model series code, according to Article 3.1
Group code (hair dryer)
Category code
4.1.3 The maximum relative humidity of the surrounding air is 90% (when the temperature is 25℃). 4.2 Installation dimensions
The installation dimensions, air outlet center height and connection method of the hair dryer should comply with the requirements in Table 2 and Figure 1. Picture
1
11
Out of the wind
Caliber
30
45
60
75
90
105
120
135
holes
number
2
2|| tt||2
A
4
4
4
Installation ruler
hole
A||tt ||80
120
160
200
240
270
300
310
Output air volume, full pressure
4.3
B
distance
M
70
80
%||tt ||140
160
180
200
215
110
120
130
150
IB588191
Table 2
Air outlet
Aperture
d
7
9bzxz.net
11
11
11
13
13
14
center high
H
30
45
55
65
80
90
105
110
Connection method
Direct
Direct
Direct
Direct
Flange
Flange
Flange
Flange
D
30
45
60
75
90
105
120
135
Air outlet connection size
F
40
55
75||tt| |90
110
125
140
145
When the hair dryer is running at full speed at rated voltage and frequency, the air volume and full pressure should not be less than The provisions of Table 3. Table 3
Gauge
Grid
mm
Air volume
m/s
Full
Pressure||tt| |Pa
30
8.33×
10-3
98
45
3.33×
10-2
294
Power factor and full efficiency
4.4
60
7.50×
10~2
539| |tt||75
14.16×
10-2
784
90
23.33x
10-2||tt ||980
105
33.33×
10-2
1078
120
45x
10-2
1176
G
10
12
12
14
mm
L|| tt||125
145
160
190
135
58.33×
10-2
1274| |tt||The power factor and full efficiency of the hair dryer when running at full speed at rated voltage and rated frequency shall not be lower than those specified in Table 4. Table 4
Air outlet inner diameter
mm
Type
No.
Full efficiency
%
Power factor|| tt||Air outlet inner diameter
mm
No.
Type
Full efficiency
%
Power factor
4.5
Noise
CZQ
5
0.55
30
90
CZT
38|| tt||0.81
CZR
8
0.82
CZQ
10
0.64
45
105
CZT
39
0.85
CzR
15
0.85| |tt||CzQ
20
0.70
60
120
CZT
40
0.86||tt ||CZR
25
0.88
CZQ
30
0.72
75
CZR
35
0.90
135
CZT
41
0.86
CZT
36
0.78| |tt||When the hair dryer operates at full speed at rated voltage and rated frequency, its A-weighted maximum noise sound power level should not exceed the requirements in Table 5. 12
Air outlet inner diameter
mm
Noise level A
dB
4.6 General structure
30
63| |tt||45
73
JB 5881-91
Table 5
60
85
75
88
90
93
105
95
120
97
4.6.1 Hair dryer fasteners and other devices should comply with the corresponding provisions of national standards, and their wearing parts should be easy to replace. 4:6.2 The installation structure of the hair dryer should be able to prevent loosening or wear caused by repeated impacts. 4.6.3 The assembly of the hair dryer impeller should be firm, reliable and well balanced. 4.7 Appearance | |tt | Obvious spots, wrinkles, bubbles, cracks, damage and adherent dirt shall not appear bubbles or rust after the damp heat test. 4.7.2 The nameplate and markings of the hair dryer should be durable. After type testing, they should not be deformed or fall off, and the pattern and writing should still be clear. 4.8 Lifespan
4.8.1 The hair dryer should still operate normally after 5000 hours of continuous use under normal conditions. 5 Test methods
The air volume test of the hair dryer should be carried out at an indoor air temperature of 20 ± 5°C. The remaining tests can be conducted indoors where the temperature is not higher than 40°C and there is no external air flow or thermal radiation. 5.1 Test instruments and meters
5.1.1 The accuracy of voltmeters, ammeters, power meters, and frequency meters used for type testing should not be lower than level 0.5, and for IED testing, the accuracy should not be lower than level 1.0.
5.1.2 The allowable error of the instrument used to measure temperature is ±0.5°C. 5.1.3 The instrument used to measure humidity has an accuracy of 1%. 5.1.4 The instrument used to measure time has an accuracy of 0.1s. 5.1.5 The instrument used to measure the rotational speed should be non-contact and its accuracy should be ±1r/min. 5.1.6 The measuring range of the compensated micro-pressure gauge or U-shaped differential pressure gauge used to measure wind pressure is 0~1960Pa, and its accuracy is 4.9Pa. 5.1.7 The C-Z type Pitot tube (dynamic pressure tube) used for measuring dynamic pressure should have a calibration curve. 5.1.8 For measuring tools used for general inspection, the error shall not be greater than 0.02mm. 5.2 Test voltage and frequency
The test shall be conducted at the rated voltage and rated frequency. The test power supply, voltage and frequency shall not exceed ±1% of the rated value. 5.3 Transportation packaging inspection
Before opening the packaging box, you must check whether the packaging and packaging boxes comply with the provisions of Articles 7.1 and 7.2 of this standard. 5.4 General inspection
Mainly check whether the manufacturing and assembly quality, nameplate, logo, etc. of the hair dryer comply with the relevant provisions of this standard. The inspection content is as follows: 5.4.1 The installation dimensions of the hair dryer should comply with the provisions of Article 4.2 of this standard. 5.4.2 The appearance inspection of the hair dryer shall comply with the provisions of Article 4.7.1 of this standard. 5.4.3 The general structural inspection of hair dryers should comply with the provisions of Article 4.6 of this standard. 5.5 Atmospheric condition measurement
5.5.1 The atmospheric pressure gauge should be placed at the location specified in Article 5.5.2. It should not be affected by the heat transfer of any high-temperature object, and should be prevented from being affected by direct sunlight and atmospheric convection.
During the test, the interval between each measurement should be 30 minutes. 13
JB 5881-91
5.5.2 The thermometer is placed in front of the air inlet of the hair dryer and measures the atmospheric temperature in the area where the speed is zero. When the difference between the average temperature of the temperature field and the maximum temperature exceeds 1℃ , the temperature field should be measured and its average value should be taken. 5.6 Measurement of air volume and full pressure characteristics
5.6.1 Test conditions
5.6.1.1 Use the duct type air outlet test device shown in Figure 2 to measure the air volume and wind pressure at the outlet end of the hair dryer, D in Figure 2 is the inner diameter of the air duct. 10.75D
0.75D
1.5D
Ground
1
Test hair dryer
5—Porous rectifier grid;||tt| |2
Connector,
0.5D
5
Figure 2
4
Test tube,
3| | tt | It is composed of device, rectification device and tapered connecting pipe. 5.6.1.3 The test pipe shall be a circular pipe. The cross-sectional area of ??the test pipe shall be the same as the area of ??the air outlet of the hair dryer as much as possible. If they are different, they shall be connected by an additional tapered connecting pipe as shown in Figure 3.
5.6.1.4 The test pipeline adopts convergent or diverging connecting pipes, and the ratio of the two cross-sectional areas does not exceed 0.7~1.3. 5.6.1.5 The tapered convergence angle of the connecting pipe should be less than 30°, and the diverging shape should be less than 14. Diffusion
Figure 3
Convergence
5.6.1.6 The inner wall of the test pipeline should be smooth and smooth, free of dust and wrinkles, and the length of the pipeline should comply with the requirements in Figure 2. 5.6.1.7 The test pipeline should be equipped with holes for measuring static pressure and dynamic pressure, and the holes should meet the following requirements. The holes for measuring static pressure are drilled on the pipe wall of the same cross-section evenly distributed along the circumference. The holes must be perpendicular to the pipe wall at the junction of the inner wall surface of the pipe a.
It must be smooth and burr-free, and the inner diameter of the hole is 3mm. Weld a short conduit for easy connection at the static pressure hole on the outer wall of the pipeline. The inner diameter of the short conduit should be consistent with the diameter of the hole for measuring static pressure, as shown in Figure 4, and then use a three-way T-shaped pipe and a connecting pipe as shown in Figure 5 As shown, they are connected to each other and connected to the pressure gauge. The inner diameter of the tee pipe used should also be consistent with the static pressure aperture. The connecting pipe should be a plastic pipe that can be put on the short conduit without leaking.
14
Short conduit
Inner side of the pipe
Picture 4
JB5881-91
Picture 5
Connect to the pressure gauge
b． To install the holes for the dynamic pressure pipe, drill two holes at 90° intervals along the circumference on the same cross-section wall perpendicular to the pipeline according to the specified positions on the pipeline to facilitate the installation of the dynamic pressure pipe, and make sure that the pipe head is placed when the dynamic pressure pipe is placed. The full pressure hole is on the measuring surface. 5.6.1.8 The size and shape of the rectifier grid (see Figure 6) shall comply with the following regulations. The pitch t of the rectifier grid (square) should be 1/4 to 1/12 of the inner diameter D of the test pipeline. b. The axial length 1 of the rectifier grid should be greater than or equal to approximately 3 times the grid pitch. Figure 6
5.6.1.9 The surface of the conical flow regulator should be smooth and the cone angle should be 60°. 5.6.2 Test procedure
5.6.2.1 Before the test, the hair dryer to be tested shall run at rated voltage and frequency for at least 1 hour. 5.6.2.2 Install the hair dryer under test according to Figure 2 and make it operate stably. During the test, the voltage variation range should not exceed ±1% of the rated value, but when reading the input power, it must be the rated voltage value. 5.6.2.3 Use a conical flow regulator to block the air outlet of the test pipeline, and use a pressure gauge to measure the static pressure on the pipe wall and the static pressure at the outlet. At this time, the dynamic pressure is zero, and the static pressure is the total pressure P. , while measuring its input power and rotational speed, and recording the ambient temperature, relative humidity, and atmospheric pressure. 3P-
5.6.2.4 Adjust the position of the conical flow regulator so that the static pressure readings of the pressure gauge are -4
10
P and when there is no throttle, the The dynamic pressure
P, 4
tube is located at the six o'clock position in Figure 7. It measures the dynamic pressure and the corresponding static pressure, simultaneously measures the input power and rotation speed, and records the ambient temperature, relative humidity, and atmospheric pressure. .
5.6.2.5. When measuring dynamic pressure, the straight pipe of the dynamic pressure pipe must be perpendicular to the pipe wall. The elbow nozzle of the dynamic pressure pipe should be forward to the direction of air flow and parallel to the axis of the air duct. The parallel deviation shall not be greater than 5°. The measurement position and number of points should be Meet the requirements of Figure 7. 15
5.6.2.6 Adjust the dynamic pressure tube and take the reading after 2 minutes. 5.6.2.7 Calculation of air volume and total pressure
a.
JB 5881--91
abg
Figure
96
abs8
Ignore air humidity and compressibility, calculate the average air flow velocity V and air flow Q on the measurement plane. V
Pa
2Pa
o
,m/s
Pa+ NPa+ NPas + VPa + VPas + NP0 = 3. 485 × 10m(P + P's
273 + t
pis
6
P'si + P's2 + P'ss + P's4 + P'ss + P's6 .6
In the formula: P. Standard atmospheric pressure, Pa;
Pp--dynamic pressure on the measuring plane, Pa
didg points,
-on the measuring plane air density, kg/m
p
P's - pipe wall static pressure, Pa;
t
air volume
where: Q-
S
D
b.
-temperature.
yuan D2
-air volume, m/s;||tt| |-Test pipe measurement plane area, m2
Test pipe diameter, m.
Blower static pressure P,
QV.S
, m2
P,P\+Pr, Pa
P = 0. 02
where: Pr——wind friction pressure loss, Pa; L
The length from the measuring point to the hair dryer outlet, m.
Hair dryer full pressure P
c.
L
D
Pd, Pa
|tt||P-Pa+Ps,Pa
5.6.2.8 Determination of full efficiency
16
t
+center#center
Lu zero
(1)
(2)
(3)
(4)
fee
(5)||tt ||(6)
(7)
coffee
(8)
fee
(9)
where: — Full efficiency,
Q-air volume, m*/s
P——full pressure, Pa;
N power when corresponding to P, W
5.7 speed measurement
QP
N
JB 5881—91
Uses non-contact tachometer to directly measure the hair dryer spindle speed. 5.8 Input power, current, and power factor measurement (10).
Use the test instrument specified in 5.1.1 to directly measure parameters such as current, voltage, power factor and power. At this time, the hair dryer is in a free blowing state
5.9 Hair dryer characteristic curve
According to the hair dryer performance test results, the aerodynamic performance of the standard air intake state at a given speed is converted, and the hair dryer characteristic curve is drawn as shown in Figure 8.
ad
Y'N
Figure 8
5.9.1 Performance data conversion
Q,m/s
Standard air intake The state refers to the pressure P. 101325Pa, the temperature is 293K and the relative humidity is 50% atmospheric density P. =1.2kg/m air volume
pressure
power
efficiency
Q. = Q n.
n
+m'/s
P. P(\)(), Pa
N,-- N(no)\(P.
), kw
n
= n||tt| |In the formula: the footnote "o" represents the parameters under the standard air intake state, Q, P, N, n, and β are the values ??measured during the hair dryer performance test. The applicable range of the above formula \
0. 5~~ 2. 0
n
The speed of the fan during inspection, r/min
5.9.2 Characteristic Curve Drawing| |tt||(11)
(12)
(13)
Draw the relationship between the pressure, power, and efficiency of the hair dryer in the standard air intake state with the flow rate as P. OneQ,N.一Q,n. A Q equal-set of curves, as shown in Figure 8.
5.10 Noise measurement
5.10.1 Test conditions
5.10.1.1 The noise test environment is a semi-anechoic chamber. Tests in other environments should comply with the regulations of GB4214. 17
JB 5881—91
5.10.1.2 Place the hair dryer on the ground in the center of the semi-anechoic chamber, and pad the bottom of the hair dryer with a 20~30mm thick elastic cushion (the area is not larger than 1.2 of the fan projection times)
5.10.2 Test method
Place the microphone at each test point 1, 2, 3, and 4 shown in (Figure 9). Use a sound level meter (A-weighted) to measure the noise and read the sound pressure level value of the noise. The logarithmic average of the four-point noise is calculated according to the following formula. (If the difference in noise value between any two points of the four noise points is less than 5dB, the arithmetic mean of the four noise points can be taken as the average sound pressure level noise of the machine). L, 10lg (≥100 1n), dB
ni=
where: Lp—average sound pressure level (A-weighted), dB; Lpi
n||tt| |-The noise sound pressure level measured at point i (A-weighted), dB; the total number of measurement points.
4
2.
900
Figure 9
5.10.3 Calculation of sound power level in semi-anechoic chamber
Lw = Lr + 101g
s
gS.
where: Lw-
~ sound power level, dB;
L average sound pressure level, dB,
S. ——Basic area, S. =1m2;
S——hemispheric envelope surface, S=2 yuan R2.
, dB
5.10.4 The sound power level when the half-envelope area of ??the hair dryer is S=2 yuan R2, R=1m. Lw=Lr+10lg2xR2=Lp+8(dB), dB
Test rule
6
18
X
(14)||tt ||(15)
(16)
A temperature.
Yuan D2
-air volume, m/s;
-test pipe measurement plane area, m2
test pipe diameter, m.
Hair dryer static pressure P,
QV.S
, m2
P,P\+Pr, Pa
P = 0. 02|| tt||In the formula: Pr——Wind friction pressure loss, Pa; L
The length from the measuring point to the outlet of the hair dryer, m.
Hair dryer full pressure P
c.
L
D
Pd, Pa
Special quantity, special quantity||tt ||P-Pa+Ps,Pa
5.6.2.8 Determination of full efficiency
16
t
+center#center
Lu Ling| |tt||(1)
(2)
(3)
(4)
Fee
(5)
(6)
(7)
coffee
(8)
charge
(9)
where: - full efficiency ,
Q-air volume, m*/s
P——full pressure, Pa;
N power when corresponding to P, W
5.7 Speed ??measurement|| tt||QP
N
JB 5881—91
uses a non-contact tachometer to directly measure the hair dryer spindle speed. 5.8 Input power, current, power factor measurement (10)
Use the test instrument specified in 5.1.1 to directly measure parameters such as current, voltage, power factor and power. At this time, the hair dryer is in a free blowing state.
5.9 Hair dryer characteristic curve
According to the hair dryer performance test results, convert it into the aerodynamic performance of the standard air intake state at a given speed, and draw the hair dryer characteristic curve as shown in Figure 8.
ad
Y'N
Figure 8
5.9.1 Performance data conversion
Q,m/s
Standard air intake The state refers to the pressure P. 101325Pa, the temperature is 293K and the relative humidity is 50% atmospheric density P. =1.2kg/m air volume
pressure
power
efficiency
Q. = Q n.
n
+m'/s
P. P(\)(), Pa
N,-- N(no)\(P.
), kw
n
= n||tt| |In the formula: the footnote "o" represents the parameters under standard air intake state, Q, P, N, n, β are the values ??measured during the hair dryer performance test. The applicable range of the above formula \
0. 5~~ 2. 0
n
The speed of the fan during inspection, r/min
5.9.2 Characteristic Curve Drawing| |tt||(11)
(12)
(13)
Draw the relationship between the pressure, power, and efficiency of the hair dryer in the standard air intake state with the flow rate as P. 1Q,N.一Q,n. A Q equal-set of curves, as shown in Figure 8.
5.10 Noise measurement
5.10.1 Test conditions
5.10.1.1 The noise test environment is a semi-anechoic chamber. Tests in other environments should comply with the regulations of GB4214. 17
JB 5881—91
5.10.1.2 Place the hair dryer on the ground in the center of the semi-anechoic chamber, and pad the bottom of the hair dryer with a 20~30mm thick elastic cushion (the area is not larger than 1.2 of the fan projection times)
5.10.2 Test method
Place the microphone at each test point 1, 2, 3, and 4 shown in (Figure 9). Use a sound level meter (A-weighted) to measure the noise and read the sound pressure level value of the noise. The logarithmic average of the four-point noise is calculated according to the following formula. (If the difference in noise value between any two points of the four noise points is less than 5dB, the arithmetic mean of the four noise points can be taken as the average sound pressure level noise of the machine). L, 10lg (≥100 1n), dB
ni=
where: Lp—average sound pressure level (A-weighted), dB; Lpi
n||tt| |-The noise sound pressure level measured at point i (A-weighted), dB; the total number of measurement points.
4
2.
900
Figure 9
5.10.3 Calculation of sound power level in semi-anechoic chamber
Lw = Lr + 101g
s
gS.
where: Lw-
~ sound power level, dB;
L average sound pressure level, dB,
S. ——Basic area, S. =1m2;
S——hemispheric envelope surface, S=2 yuan R2.
, dB
5.10.4 The sound power level when the half-envelope area of ??the hair dryer is S=2 yuan R2, R=1m. Lw=Lr+10lg2xR2=Lp+8(dB), dB
Test rule
6
18
X
(14)||tt ||(15)
(16)
A temperature.
Yuan D2
-air volume, m/s;
-test pipe measurement plane area, m2
test pipe diameter, m.
Hair dryer static pressure P,
QV.S
, m2
P,P\+Pr, Pa
P = 0. 02|| tt||In the formula: Pr——Wind friction pressure loss, Pa; L
The length from the measuring point to the outlet of the hair dryer, m.
Hair dryer full pressure P
c.
L
D
Pd, Pa
Special quantity, special quantity||tt ||P-Pa+Ps,Pa
5.6.2.8 Determination of full efficiency
16
t
+center#center
Lu Ling| |tt||(1)
(2)
(3)
(4)
Fee
(5)
(6)
(7)
coffee
(8)
charge
(9)
where: - full efficiency ,
Q-air volume, m*/s
P——full pressure, Pa;
N power when corresponding to P, W
5.7 Speed ??measurement|| tt||QP
N
JB 5881—91
uses a non-contact tachometer to directly measure the hair dryer spindle speed. 5.8 Input power, current, power factor measurement (10)
Use the test instrument specified in 5.1.1 to directly measure parameters such as current, voltage, power factor and power. At this time, the hair dryer is in a free blowing state.
5.9 Hair dryer characteristic curve
According to the hair dryer performance test results, convert it into the aerodynamic performance of the standard air intake state at a given speed, and draw the hair dryer characteristic curve as shown in Figure 8.
ad
Y'N
Figure 8
5.9.1 Performance data conversion
Q,m/s
Standard air intake The state refers to pressure P. 101325Pa, the temperature is 293K and the relative humidity is 50% atmospheric density P. =1.2kg/m air volume
pressure
power
efficiency
Q. = Q n.
n
+m'/s
P. P(\)(), Pa
N,-- N(no)\(P.
), kw
n
= n||tt| |In the formula: the footnote "o" represents the parameters under the standard air intake state, Q, P, N, n, and β are the values ??measured during the hair dryer performance test. The applicable range of the above formula \
0. 5~~ 2. 0
n
The speed of the fan during inspection, r/min
5.9.2 Characteristic Curve Drawing| |tt||(11)
(12)
(13)
Draw the relationship between the pressure, power, and efficiency of the hair dryer in the standard air intake state with the flow rate as P. OneQ,N.一Q,n. A Q equal-set of curves, as shown in Figure 8.
5.10 Noise measurement
5.10.1 Test conditions
5.10.1.1 The noise test environment is a semi-anechoic chamber. Tests in other environments should comply with the regulations of GB4214. 17
JB 5881—91
5.10.1.2 Place the hair dryer on the ground in the center of the semi-anechoic chamber, and pad the bottom of the hair dryer with a 20~30mm thick elastic cushion (the area is not larger than 1.2 of the fan projection times)
5.10.2 Test method
Place the microphone at each test point 1, 2, 3, and 4 shown in (Figure 9). Use a sound level meter (A-weighted) to measure the noise and read the sound pressure level value of the noise. The logarithmic average of the four-point noise is calculated according to the following formula. (If the difference in noise value between any two points of the four noise points is less than 5dB, the arithmetic mean of the four noise points can be taken as the average sound pressure level noise of the machine). L, 10lg (≥100 1n), dB
ni=
where: Lp—average sound pressure level (A-weighted), dB; Lpi
n||tt| |-The noise sound pressure level measured at point i (A-weighted), dB; the total number of measurement points.
4
2.
900
Figure 9
5.10.3 Calculation of sound power level in semi-anechoic chamber
Lw = Lr + 101g
s
gS.
where: Lw-
~ sound power level, dB;
L average sound pressure level, dB,
S. ——Basic area, S. =1m2;
S——hemispheric envelope surface, S=2 yuan R2.
, dB
5.10.4 The sound power level when the half-envelope area of ??the hair dryer is S=2 yuan R2, R=1m. Lw=Lr+10lg2xR2=Lp+8(dB), dB
Test rule
6
18
X
(14)||tt ||(15)
(16)
n. A Q equal-set of curves, as shown in Figure 8.
5.10 Noise measurement
5.10.1 Test conditions
5.10.1.1 The noise test environment is a semi-anechoic chamber. Tests in other environments should comply with the regulations of GB4214. 17
JB 5881—91
5.10.1.2 Place the hair dryer on the ground in the center of the semi-anechoic chamber, and pad the bottom of the hair dryer with a 20~30mm thick elastic cushion (the area is not larger than 1.2 of the fan projection times)
5.10.2 Test method
Place the microphone at each test point 1, 2, 3, and 4 shown in (Figure 9). Use a sound level meter (A-weighted) to measure the noise and read the sound pressure level value of the noise. The logarithmic average of the four-point noise is calculated according to the following formula. (If the difference in noise value between any two points of the four noise points is less than 5dB, the arithmetic mean of the four noise points can be taken as the average sound pressure level noise of the machine). L, 10lg (≥100 1n), dB
ni=
where: Lp—average sound pressure level (A-weighted), dB; Lpi
n||tt| |-The noise sound pressure level measured at point i (A-weighted), dB; the total number of measurement points.
4
2.
900
Figure 9
5.10.3 Calculation of sound power level in semi-anechoic chamber
Lw = Lr + 101g
s
gS.
where: Lw-
~ sound power level, dB;
L average sound pressure level, dB,
S. ——Basic area, S. =1m2;
S——hemispheric envelope surface, S=2 yuan R2.
, dB
5.10.4 The sound power level when the half-envelope area of ??the hair dryer is S=2 yuan R2, R=1m. Lw=Lr+10lg2xR2=Lp+8(dB), dB
Test rule
6
18
X
(14)||tt ||(15)
(16)
n. A Q equal-set of curves, as shown in Figure 8.
5.10 Noise measurement
5.10.1 Test conditions
5.10.1.1 The noise test environment is a semi-anechoic chamber. Tests in other environments should comply with the regulations of GB4214. 17
JB 5881—91
5.10.1.2 Place the hair dryer on the ground in the center of the semi-anechoic chamber, and pad the bottom of the hair dryer with a 20~30mm thick elastic cushion (the area is not larger than 1.2 of the fan projection times)
5.10.2 Test method
Place the microphone at each test point 1, 2, 3, and 4 shown in (Figure 9). Use a sound level meter (A-weighted) to measure the noise and read the sound pressure level value of the noise. The logarithmic average of the four-point noise is calculated according to the following formula. (If the difference in noise value between any two points of the four noise points is less than 5dB, the arithmetic mean of the four noise points can be taken as the average sound pressure level noise of the machine). L, 10lg (≥100 1n), dB
ni=
where: Lp—average sound pressure level (A-weighted), dB; Lpi
n||tt| |-The noise sound pressure level measured at point i (A-weighted), dB; the total number of measurement points.
4
2.
900
Figure 9
5.10.3 Calculation of sound power level in semi-anechoic chamber
Lw = Lr + 101g
s
gS.
where: Lw-
~ sound power level, dB;
L average sound pressure level, dB,
S. ——Basic area, S. =1m2;
S——hemispheric envelope surface, S=2 yuan R2.
, dB
5.10.4 The sound power level when the half-envelope area of ??the hair dryer is S=2 yuan R2, R=1m. Lw=Lr+10lg2xR2=Lp+8(dB), dB
Test rule
6
18
X
(14)||tt ||(15)
(16)
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