MT/T 249-2019 English PDF (MT/T249-2019)

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MT/T 249-2019: YBSD series flameproof mining type double speed three-phases asynchronous motor
MT/T 249-2019
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MT
COAL INDUSTRY STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
Replacing MT/T 249-1997
YBSD series flameproof mining type double speed three-
phases asynchronous motor
ISSUED ON: DECEMBER 29, 2018
IMPLEMENTED ON: JULY 01, 2019
Issued by: State Administration of Coal Mine Safety
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Types and basic parameters ... 6
4 Technical requirements ... 7
5 Test methods ... 14
6 Inspection rules ... 16
7 Marking, packaging, transportation, storage ... 18
Appendix A (Informative) Installation dimension and tolerance of YBSD series
flameproof mining type double speed three-phases asynchronous motor ... 21
YBSD series flameproof mining type double speed three-
phases asynchronous motor
1 Scope
This standard specifies the type and basic parameters, technical requirements, test
methods, inspection rules, marking, packaging, transportation, storage of YBSD series
flameproof mining type double speed three-phases asynchronous motor (hereinafter
referred to as motors).
This standard applies to the driving motors of scraper conveyors, belt conveyors,
scraper loader, other similar machinery in coal mine underground working face.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB 755 Rotating electrical machines - Rating and performance
GB/T 1032-2012 Test procedures for three-phase induction motors
GB/T 1993 Cooling methods for rotating electrical machines
GB/T 2423.4 Environmental testing for electric and electronic products - Part 2: Test
method - Test Db: Damp heat, cyclic (12h + 12h cycle)
GB 3836.1-2010 Explosive atmospheres - Part 1: Equipment - General requirements
GB 3836.2-2010 Explosive atmospheres - Part 2: Equipment protection by
flameproof enclosures “d”
GB 3836.3-2010 Explosive atmospheres - Part 3: Equipment protection by increased
safety e
GB/T 4772.1 Dimensions and output series for rotating electrical machines - Part 1:
Frame numbers 56 to 400 and flange numbers 55 to 1 080
GB/T 4942.1-2006 Degrees of protection provided by the integral design of rotating
electrical machined (IP code) - Classification
GB 10068 Mechanical vibration of certain machines with shaft heights 56 mm and
higher-measurement evaluation and limits of vibration severity
GB/T 10069.1 Measurement of airborne noise emitted by rotating electrical
machines and the noise limits - Part 1: Method for the measurement of airborne
noise emitted by rotating electrical machines
GB/T 10111 Generation of random numbers and procedures applied to sampling
inspection for product quality
GB/T 22714 Test specifications of interturn insulation of form-wound winding for
AC low-voltage electrical machines
GB/T 22715 Impulse voltage withstand levels of form-wound stator coils for
rotating a. c. machines
GB/T 22719.1 Interturn insulation of random-wound winding for AC low-voltage
electrical machines - Part 1: Test methods
AQ/T 1043 Mining product safety signs
3 Types and basic parameters
3.1 Type
3.1.1 The motor shall be made of explosion-proof type for mining, according to the
provisions of GB 3836.1 and GB 3836.2. The explosion-proof mark is Ex d I Mb
[Translator: should be “Exd I Mb”].
3.1.2 The degree of protection of the overall structure of the motor shall comply with
IP54, which is specified in GB/T 4942.1-2006.
3.1.3 The cooling method of the motor is water-cooled or air-cooled, which shall
comply with the provisions of GB/T 1993. The cooling method is marked as IC3W7 or
IC411.
3.1.4 The installation dimension and tolerance of the motor shall be designed and
manufactured, according to the order agreement between the user and the manufacturer.
The deviation shall comply with the provisions of GB/T 4772.1 (refer to Appendix A).
3.2 Basic parameters
3.2.1 The rating of the motor shall be in accordance with the provisions of GB 755, with
the continuous duty system (SI) as the benchmark rating, OR other duty systems as the
water in the water channel. The temperature limit of the stator winding end shall not
exceed the provisions in Table 5.
4.13 The thermal insulation resistance of the motor's stator winding shall not be lower
than 0.38 MΩ (when the rated voltage is 380 V), 0.66 MΩ (when the rated voltage is
660 V), 1.14 MΩ (when the rated voltage is 1140 V) or 3.3 MΩ (when the rated voltage
is 3300 V).
4.14 The stator winding of the motor shall be able to withstand the power frequency
withstand voltage test of 1 min, to the casing and the windings, without breakdown.
The frequency of the test voltage is 50 Hz. The waveform is as close as possible to a
sine wave. The effective value of the test voltage is (2U + 1000) V (U is the rated voltage,
in volts).
4.15 The AC low-voltage motor shall be able to withstand the inter-turn impulse
withstand voltage test of the windings, which are required by formula (1). The tolerance
of the impulse voltage peak value is ±3.0%; the wave front time is 0.2 μs; the tolerance
is .
Where:
U'P - The peak value of the insulation impulse test voltage between turns of the
motor's stator winding, in volts (V);
K1 - The voltage coefficient, which takes 1.40;
K2 - The running coefficient, which takes 1.20;
UG - The power frequency withstand voltage test value (effective value) of the
insulation of the stator winding of the motor to the casing (ground), in volts (V).
4.16 For a motor, which has a rated voltage of 3.3 kV, the stator's forming coil shall be
able to withstand the surge voltage level test, which has a wave front time of 0.2 μs; the
impulse voltage test value (peak value) is 12 kV.
4.17 The stator winding of the motor shall be able to withstand the alternating damp
heat test, which has a severe level of 40 °C and a period of 12 d. After the test, the
insulation resistance shall be not less than 1.14 MΩ (at a rated voltage of 380 V), 1.98
MΩ (at a rated voltage of 660 V), 3.42 MΩ (at a rated voltage of 1140 V) or 9.9 MΩ
(at a rated voltage of 3300 V). Meanwhile, it shall be capable of withstanding the power
frequency withstand voltage test, without flashover breakdown. The effective value of
the test voltage is 0.85 times the value specified in 4.14; the flame-proof surface shall
not be corroded.
4.18 The noise value of the A-weighted sound power level, which is measured when
5 Test methods
5.1 The power supply for the motor test shall comply with the provisions of 4.2 in GB/T
1032-2012. The measuring instrument shall comply with the provisions of 4.3 in GB/T
1032-2012.
5.2 The degree of protection test of the overall structure of the motor shall be carried
out, in accordance with the provisions of GB/T 4942.1.
5.3 Appropriate measuring tools shall be used, for the inspection of the external
dimensions and installation dimensions of the motor and the flame-proof parameters.
5.4 The determination of motor efficiency and power factor shall be carried out, in
accordance with the provisions of Chapter 7, Chapter 8, Chapter 10, Chapter 11 in GB/T
1032-2012; the E1 method is preferred.
5.5 Determination of motor's locked-rotor torque multiples and locked-rotor current
multiples shall be carried out, in accordance with the provisions of Chapter 9 in GB/T
1032-2012.
5.6 The determination of the maximum torque of the motor shall be carried out,
according to the provisions of 12.1 in GB/T 1032-2012.
5.7 The determination of the minimum torque of the motor shall be carried out,
according to the provisions of 12.2 in GB/T 1032-2012.
5.8 The temperature rise test of the motor shall be carried out, according to the
provisions in Chapter 6 of GB/T 1032-2012.
5.9 The motor overspeed test shall be carried out, in accordance with the provisions in
12.8 of GB/T 1032-2012.
5.10 The motor's short-time over-torque test shall be carried out, in accordance with the
provisions of 12.4 in GB/T 1032-2012.
5.11 The overload test of the motor shall be carried out, under high-speed operation.
After the rated operation reaches a thermally stable state, continue to operate at 120%
of the rated output power for 20 minutes. Use the embedded thermometer, to measure
the temperature of the end of the stator winding.
5.12 During the water cut-off test of the motor, first run the rated motor to a thermally
stable state. Then cut off the cooling water source (keep the water in the motor's cooling
water channel). Continue to run at the rated value for 10 minutes. Use the embedded
thermometer method, to measure the stator's winding end temperature.
5.13 Determination of thermal insulation resistance of motor windings shall be carried
out, in accordance with the provisions of 5.1 in GB/T 1032-2012.
5.14 The power frequency withstand voltage test of the motor shall be carried out,
according to the provisions in 12.6 of GB/T 1032-2012.
5.15 The inter-turn impulse voltage test of AC low-voltage scattered-winding motors
shall be carried out, in accordance with the provisions of GB/T 22719.1. The impulse
voltage level test of the formed coil shall be carried out, in accordance with the
provisions of GB/T 22714.
5.16 The 3.3 kV forming coil winding's resistance to steep wave front impulse voltage
level test shall be carried out, according to the provisions of GB/T 22715.
5.17 The alternating damp heat test of the motor shall be carried out, in accordance with
the provisions of GB/T 2423.4.
5.18 Determination of motor noise shall be carried out, according to the provisions of
GB/T 10069.1.
5.19 The measurement of motor vibration shall be carried out, in accordance with the
provisions of GB 10068.
5.20 The three-phase unbalance degree test of motor's no-load current shall be carried
out, according to the provisions of Chapter 8 in GB/T 1032-2012. At the same time,
check the operation of the motor bearing and the direction of rotation. When checking
the direction of rotation, attention shall be paid to make the phase sequence of the power
supply consistent with the alphabetical sequence of the motor's outlet end.
5.21 During the water pressure test of the motor's cooling water channel, block the
water outlet of the water channel. Increase the water pressure of the water inlet, to the
required value of the test. Keep it for 5 minutes. Observe whether the water pressure
drops. At the same time, check whether there is leakage and whether the shell structure
is damaged OR whether the water channel is deformed.
5.22 The shell's static pressure test shall be carried out, according to the requirements
in 15.1.3 of GB 3836.2-2010. The shell pressure test and the internal ignition non-
transmission test shall be carried out, according to the requirements of Chapter 15 in
GB 3836.2-2010.
5.23 The impulse test of the motor's flameproof enclosure shall be carried out, in
accordance with the provisions in 26.4.2 of GB 3836.1-2010.
5.24 The torsion test of the insulating sleeve shall be carried out, according to the
provisions in 26.6 of GB 3836.1-2010.
5.25 The cable entry device's clamping test and mechanical strength test shall be carried
out, in accordance with the provisions of Appendix A in GB 3836.1-2010. The sealing
f) When requested by relevant state agencies.
6.3.2 Type inspection items are as shown in Table 9.
6.3.3 The samples for type inspection shall be selected from the products, which have
passed the exit-factory inspection, by the simple random sampling method, as specified
in GB/T 10111. The number of samples in batches of more than 20 units is two; the
number of samples in batches of less than 20 units is one. This project is judged as
qualified, after all type inspection items are qualified. If there is any nonconformance,
double sample is taken for inspection. If there are still unqualified items, the batch of
products is unqualified.
7 Marking, packaging, transportation, storage
7.1 The motor casing is marked with "Exd I Mb" embossed marking, painted in red, has
a safety sign "MA" in accordance with AQ 1043.
7.2 The material of the nameplate shall be chemically resistant material, such as bronze,
brass, or stainless steel. The scoring method shall be such, that the writing is not easily
erased, during the entire use of the motor.
7.3 The nameplate shall be installed on the obvious part of the main body of the motor.
The items, which shall be marked on the nameplate, are as follows:
a) The name of the manufacturer;
b) The name and model of the motor;
c) Flame-proof sign;
d) Degree of protection;
e) Work system;
f) Rated power;
g) Rated frequency;
h) Rated voltage;
i) Rated current;
j) Rated speed;
k) Heat resistance class;
l) Wiring method;
m) Cooling water flow;
n) Cooling water pressure;
o) Date of exit-factory and serial number;
p) Standard number;
q) Flame-proof certificate number;
r) Safety sign number;
s) Mass.
Note: The items m) and n) only need to be marked for water-cooled motors.
7.4 The motor's packing list, product instruction manual, product certificate shall be
provided to the user, along with each motor.
7.5 The flat key of the shaft extension of the motor shall be bound on the shaft. The
shaft extension, spigot, and flange shall be protected against rust AND have protection
measures.
7.6 When the motor leaves the factory and during storage, measures shall be taken to
prevent rust and freeze cracking, in the cooling water channel. The water in the water
channel shall be drained. The water inlet and outlet shall be equipped with sealing plugs.
7.7 The motor packaging shall be able to prevent moisture and damage, due to poor
packaging, within a year fro...