Skip to product information
1 of 12

PayPal, credit cards. Download editable-PDF and invoice in 1 second!

GB/T 5171.21-2016 English PDF (GBT5171.21-2016)

GB/T 5171.21-2016 English PDF (GBT5171.21-2016)

Regular price $605.00 USD
Regular price Sale price $605.00 USD
Sale Sold out
Shipping calculated at checkout.
Quotation: In 1-minute, 24-hr self-service. Click here GB/T 5171.21-2016 to get it for Purchase Approval, Bank TT...

GB/T 5171.21-2016: Small power motors -- Part 21: General test methods

This Part of GB/T 5171 specifies terms and definitions, symbols involved in general test methods for small power motors, basic requirements for the test, test preparation, temperature rise test, efficiency determination, as well as locked-rotor test and other test methods.
GB/T 5171.21-2016
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 29.160.30
K 20
Small power motors - Part 21: General test methods
ISSUED ON: AUGUST 29, 2016
IMPLEMENTED ON: MARCH 01, 2017
Issued by: General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions, symbols ... 6
3.1 Terms and definitions ... 6
3.2 Symbols ... 8
4 Basic requirements for test ... 11
4.1 Test ambient conditions ... 11
4.2 Test power ... 11
4.3 Use of measuring instruments... 12
5 Test preparation ... 20
5.1 Determination of insulation resistance ... 20
5.2 Determination of cold-state winding temperature ??1 and cold-state winding resistance R1 ... 21
6 Temperature rise test ... 21
6.1 Overview ... 21
6.2 General description ... 21
6.3 Determination of cooling medium temperature at the end of temperature rise test ... 22
6.4 Temperature measurement methods for motor winding and other parts ... 22 6.5 Temperature rise test method ... 23
6.6 Calculation of winding working temperature ??2 ... 26
6.7 Calculation of winding temperature rise ???? ... 27
6.8 Corrected to reference cooling medium temperature ... 27
7 Determination of efficiency ... 28
7.1 Overview ... 28
7.2 Direct method (method A) ... 29
7.3 Loss analysis method (method B) ... 31
7.4 Calculation of AC motor power factor ... 41
8 Locked-rotor test ... 41
9 Other test items ... 42
9.1 Dimension inspection ... 42
9.2 Short-time over-torque test ... 46
9.3 Determination of maximum torque ... 46
9.4 Determination of minimum torque ... 47
9.5 Determination of moment of inertia ... 49
9.6 Magnetic stability inspection of permanent magnet motors ... 50
9.7 Determination of noise ... 50
9.8 Determination of vibration ... 51
9.9 Electric strength test ... 51
9.10 Repeat electric strength test ... 52
9.11 Inter-turn insulation electric strength test ... 52
9.12 Leakage current test at working temperature ... 53
9.13 Accidental overcurrent test ... 55
9.14 Over-speed test ... 55
9.15 Protection level test ... 56
9.16 Damp heat test ... 56
9.17 Other ambient tests ... 56
9.18 Other safety tests ... 56
9.19 Operating time limit test ... 56
Annex A (normative) Correction methods for instrument loss ... 60
Annex B (normative) Determination of correction value Tc of dynamometer torque reading ... 62
Annex C (normative) Specification for selection, preparation, arrangement, installation and connection of thermocouples ... 63
Annex D (informative) Test report template for loss analysis method (method B) ... 66
Bibliography ... 68
Small power motors - Part 21: General test methods
1 Scope
This Part of GB/T 5171 specifies terms and definitions, symbols involved in general test methods for small power motors, basic requirements for the test, test preparation, temperature rise test, efficiency determination, as well as locked-rotor test and other test methods.
This Part is applicable to the products defined in GB/T 5171.1.
The special test items and methods of various types of small power motors that are not specified in this Part need to be supplemented in the test method standards for this type of small power motors.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 755, Rotating electrical machines - Rating and performance
GB/T 1958, Geometrical Product Specifications (GPS) - Geometrical
tolerance - Verification
GB/T 2423 (all parts), Environmental testing - Part 2: Test methods
GB/T 2828.1, Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 4942.1, Degrees of Protection Provided by the Integral Design of
Rotating Electrical Machined (IP Code) - Classification
GB/T 5171.1, Small Power Motors - Part 1: General Technical Requirements 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 12113-2003, Methods of measurement of touch current and protective [GB/T 2900.25-2008, definition 411-53-28]
3.1.5 locked-rotor test
a test to determine the locked-rotor torque and the locked-rotor current, when the motor is energized and the rotor is blocked
[GB/T 2900.25-2008, definition 411-53-32]
3.1.6 over-speed test
a test carried out on the motor to determine whether the motor rotor can meet the specified overspeed requirements
[GB/T 2900.25-2008, definition 411-53-39]
3.1.7 short-time over-torque test
a test to determine the ability of the motor to withstand the specified over-torque multiples within a specified time
[GB/T 2900.27-2008, definition 9.7]
3.1.8 accidental over-current test
a test to determine the ability of the motor to withstand the specified overcurrent multiples within a specified time
[GB/T 2900.27-2008, definition 9.9]
3.1.9 operating time limit test
a test to determine the normal operation period that the manufacturer
guarantees to the user under the specified conditions
[GB/T 2900.27-2008, definition 9.12]
3.1.10 no-load test
a test without effective mechanical output on the shaft when the motor is running
3.1.11 line-to-line resistance
the arithmetic average of the resistance between the terminals of each two- phase power supply connection of a multi-phase AC motor
NOTE 1: For Y-connection three-phase motors, the phase resistance is 0.5 times the line- to-line resistance. For ??-connection three-phase motors, the phase resistance is 1.5 times Pc - Constant loss (W);
Pfe - Iron consumption (W);
Pfw - Friction and wind resistance loss (W);
Pfw0 - Friction and windage loss (W) at synchronous speed;
Pk - Locked-rotor input power (W);
PLL - Additional load loss (W);
PLr - Stray loss (W);
Pr - Rotor winding loss (W);
Pr,?? - Rotor winding loss (W) corrected to 25??C reference cooling medium temperature;
Ps - Stator winding loss (W);
Ps,?? - Stator winding loss (W) corrected to 25??C reference cooling medium temperature;
PT - Total loss (W);
P0 - No-load input power (W);
P1 - Input power (W);
P1,?? - Input power (W) corrected to 25??C reference cooling medium temperature; P2 - Output power (W);
P2c - Corrected output power (W);
p - Number of pole pairs;
Q - Gravity of code and container (N);
R - Winding resistance;
Rll,0 - Interpolated winding resistance (??) during no-load test (each voltage point);
R0 - Winding resistance (??) during no-load test;
R1 ?€? Cold-state winding resistance (??);
R2 - In the temperature rise test, the winding resistance measured after the n - Harmonic order (does not include the multiples of 3 and 3 for three-phase AC motors);
k=13.
When conducting temperature rise and efficiency tests, the voltage tolerance of the AC power supply for the test shall not be greater than 0.5%. The frequency fluctuation of the AC power supply shall be within ??0.1% of the rated frequency. The average power supply frequency shall be within ??0.1% of the test frequency. 4.2.2 Three-phase AC power supply
For three-phase AC power supply, in addition to meeting the requirements in 4.2.1, the negative sequence component of the three-phase voltage system shall be less than 0.5% of the positive sequence component, and the influence of zero sequence component shall be eliminated. The negative sequence
component of the measuring current system can be used to replace the
negative sequence component of the measuring voltage system. The negative sequence component of the current system shall not exceed 2.5% of the
positive sequence component.
4.2.3 DC power supply
The DC power supply equipment used in the test shall not exceed 0.5% of the nominal source voltage and the output voltage tolerance of each output under half-rated load. For each output, within the specified load range and under the most unfavorable supply voltage, the load regulation rate is not more than 0.2%. 4.3 Use of measuring instruments
4.3.1 General
The ambient conditions during the test shall be within the range recommended by the equipment manufacturer. If applicable, temperature corrections shall be made to the measured values according to the manufacturer's equipment
instructions.
Digital measuring instruments shall be used whenever possible.
Since the accuracy of analog measuring instruments is usually expressed as a percentage of full scale, the range of the measuring instrument selected during the test shall be as small as possible as the actual value. The observation value shall be within one-third of the instrument range to the full-scale range. The range of the measuring instrument, especially the current sensor, shall be adapted to the power of the motor being tested.
Parasitic loads shall be minimized through shaft alignment adjustments and the use of flexible couplings.
4.3.4 Measurement of rotating speed
4.3.4.1 General
The indication error of the speed measuring instrument shall be less than ??0.1% of the speed range or less than 1r/min. Take the one with the smallest error between the two.
For asynchronous motors, the induction coil method or flash method can also be used to measure the slip rate to replace the speed measurement.
The measurement methods of motor speed (slip rate) mainly include:
- Digital speed (or slip) measuring instrument;
- Induction coil method;
- Measuring slip ratio by speed measuring instrument;
- Digital frequency meter;
- Stroboscopic test method.
If the induction coil method or the stroboscopic test method is used to directly measure the slip rate, the power supply shall be the power supply for the tested motor. It is not recommended to use direct mechanical contact method that affects the running state of the motor.
4.3.4.2 Digital speed (or slip rate) measuring instrument method
Install a photoelectric reflective mark, transmissive grating disc or magneto- electric induction device that does not generate significant load when the motor rotates on the rotating shaft. Transform the speed signal into pulse signal by photoelectric sensor or magnetoelectric sensor. The measuring instrument directly displays the speed (or slip rate) of the tested motor.
4.3.4.3 Induction coil method
For asynchronous motors, a multi-turn coil with iron core can be placed on the motor casing. And connect with magnetoelectric galvanometer or cathode
oscilloscope. During the test, use a stopwatch to measure the time t (s) required for the full swing of the galvanometer pointer or the oscilloscope waveform for N times. The slip rate s is calculated according to formula (3).
thermometers and alcohol thermometers), semiconductor thermometers, and non-embedded thermocouples or resistance thermometers.
When used to measure the temperature of the parts of the motor, the
thermometer shall be close to the surface of the measured point. To measure the temperature of the surface of the contact point, the heat conduction from the measured point to the thermometer shall be as good as possible. Use thermal insulation material to cover the temperature measurement part of the thermometer, so as to avoid the influence of the surrounding cooling medium. When used to measure the temperature of parts with strong alternating or moving magnetic fields, mercury thermometers shall not be used.
4.3.6.3 Thermocouple method
This method is recommended for the measurement of surface temperature of motor parts. It is not recommended to use this method to measure the
temperature of the winding.
When using a thermocouple to measure the temperature of the winding, it shall consider: because the thermocouple reading lags behind the temperature
change of the winding, when the motor is powered off, the temperature of the thermocouple may continue to rise. Therefore, the temperature of the motor winding shall record its maximum temperature. The temperature may be
reached after power failure.
The specifications for the selection, preparation, arrangement, installation and connection of thermocouples are shown in Annex C.
4.3.6.4 Resistance method
The resistance method determines the temperature of the winding based on the relationship that the resistance of the winding increases correspondingly after the temperature rises. What it measures is the average temperature of the winding.
Resistance method includes direct measurement method and live
measurement method (see 6.5.3 and 6.5.4).
4.3.7 Determination of winding resistance
4.3.7.1 General
Winding resistance R can be determined by appropriate methods such as
double-arm bridge, single-arm bridge or DC voltmeter-ammeter method.
For permanent magnet DC motors, R is the total resistance of all coils that load When measuring the winding insulation resistance, if the beginning and end of each winding circuit have been led out of the casing, then the insulation group of each winding circuit to the casing and the windings shall be measured separately. If the winding has been connected inside the motor, when only the wire end is drawn out, measure the insulation resistance of the wire end to the casing.
For capacitor motors, the capacitor shall be connected to the secondary winding circuit (unless otherwise agreed).
After the insulation resistance measurement is over, the winding shall be discharged to the ground.
5.2 Determination of cold-state winding temperature ??1 and cold-state
winding resistance R1
Put the motor indoors for a period of time. Use a thermometer to measure the temperature of the end of the motor winding or the iron core. When the
difference between the measured temperature and the temperature of the
cooling medium does not exceed 2K, then the measured temperature is the temperature of the cold-state winding ??1. If the temperature of the winding end or the iron core cannot be measured, the temperature of the casing is allowed to replace it.
While measuring the cold-state winding temperature ??1, measure the cold-state winding resistance R1, see 4.3.7.
6 Temperature rise test
6.1 Overview
The purpose of the temperature rise test is to determine the temperature rise of windings and certain parts of the motor that are higher than the temperature of the cooling medium when the motor is running under specified load conditions. The temperature measurement method is selected according to 4.3 and the relevant provisions of this Clause.
6.2 General description
Measures shall be taken during the test to minimize the change in the
temperature of the cooling medium.
The tested motor shall be protected to block the influence of airflow generated by other machinery or the surrounding environment on the tested motor.
Generally, a very slight airflow is enough to cause a large deviation in the results of the temperature rise test. Environmental conditions that cause rapid changes 6.5 Temperature rise test method
6.5.1 Determination of load
6.5.1.1 Overview
The motor shall be able to run under its rated load or less than its rated load. The motor that can run at multiple speeds shall be able to run at the minimum, intermediate and maximum speeds with a rated load. During this process, all parts of the motor shall not reach too high temperature.
For voltage regulating motors that work in a voltage range and motors with multiple working conditions, the temperature rise test shall be carried out under the most unfavorable conditions that may occur in normal use.
For motors with thermal protector or thermal fuse without fixed installation position, during rated load temperature rise test and no-load temperature rise test, the installation position of the motor shall be such that the thermal protector or thermal fuse is in a position with the highest possible temperature (usually in the upper position of the motor winding). During the test, the thermal protector or thermal fuse is not allowed to operate.
6.5.1.2 Motors with clear rated operating point
This kind of motors use direct method. Apply a rated load to the motor under test through a dynamometer (or a load motor with a torque measuring
instrument). Test under rated frequency and rated voltage.
For single-phase asynchronous motors running with capacitors, the
temperature rise test shall be assessed at the point of maximum loss. The maximum loss point is determined by testing among the rated point, the no-load point, and the intermediate speed points of the above two points.
For capacitor-running asynchronous motors and dual-value capacitor
asynchronous motors, the temperature rise at no load shall also be measured. 6.5.1.3 Motors with actual load
This type of motor has actual load during normal operation, and these actual loads have a greater impact on the temperature rise of the motor. Therefore, when the temperature rise test is performed, it is necessary to carry the actual load and perform the test at the rated frequency and rated voltage.
6.5.2 Duration of various motor temperature rise tests
6.5.2.1 Maximum continuous rating (or S1 working system) motor
The test shall be continued until all parts of the motor reach a thermally stable 6.5.2.6 Locked-rotor temperature rise test
For single-phase asynchronous motors with capacitor start and resistance start, the locked-rotor temperature rise test shall also be carried out.
The tested motor shall quickly block the rotor in the hot state or after the temperature rise test is over. Apply a rated voltage. Maintain 5s. Immediately measure the resistance of the primary and secondary windings to obtain the temperature rise of the windings.
6.5.3 Determination of the winding resistance R2 and temperature of each part of motor after the motor is stopped
After the temperature rise test is over, the power shall be cut off immediately. Carefully arrange the test procedures and the appropriate number of test personnel. Measure the winding resistance readings and the temperature of each part of the motor as soon as possible.
From the moment of power failure, if the winding resistance and temperature are measured within 15s after the power is cut off, then use this resistance value to calculate the winding temperature rise. The measured temperature of each part of the motor does not need to be corrected.
If it cannot be measured within 15s, additional readings shall be taken as soon as possible at intervals of 20s~60s. Plot these readings as a function of time. Use extrapolation to correct to the moment of power failure. That is, measure resistance R or temperature ?? and corresponding time t. There shall be no less than 5 points. Draw R=f(t) or ??=f(t) curve on graph paper or semi-logarithmic graph paper, as shown in Figure 3. The extension curve intersects the vertical axis. Its intersection point is the resistance value or temperature value at...

View full details