JB/T 9008.2-2015 English PDF (JB/T9008.2-2015)

JB/T 9008.2-2015: Electric wire rope hoists - Part 2: Testing method
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JB/T 9008.2-2015
JB
MACHINERY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 53.020.99
J 80
Record No.: 51509-2015
Replacing JB/T 9008.2-2004
Electric Wire Rope Hoists – Part 2: Testing Method
ISSUED ON: OCTOBER 10, 2015
IMPLEMENTED ON: MARCH 01, 2016
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 4
1 Scope ... 6
2 Normative References ... 6
3 Basic Requirements for Test ... 7
4 Test Content and Method of Electric Hoist ... 8
4.1 General inspection ... 8
4.2 Inspection of insulation ... 9
4.3 Inspection of grounding protection ... 9
4.4 No-load test ... 9
4.5 Voltage-drop test and voltage-rise test ... 10
4.6 Determining the braking sliding amount ... 10
4.7 Measurement of the lifting and descending speed ... 10
4.8 Measurement of the noise of the lifting mechanism ... 11
4.9 Current and voltage test ... 13
4.10 Safety brake test ... 13
4.11 Static load test ... 13
4.12 Dynamic load test ... 13
4.13 Function test of load lifting limiter ... 14
4.14 Operating mechanism test ... 14
4.15 Appearance coating quality ... 15
4.16 Energy efficiency test ... 15
4.17 Service life test ... 15
5 Test Content and Method of the Motor ... 17
5.1 General inspection ... 17
5.2 No-load test ... 17
5.3 Blocked rotor test ... 17
5.4 Withstand voltage test of the winding to the casing ... 17
5.5 Determination of the static braking torque of the motor ... 17
5.6 Determination of the motor noise ... 18
5.7 Inter-turn insulation test ... 18
5.8 Rotor dynamic balance test ... 18
5.9 Motor load test ... 18
5.10 Determination of the maximum torque ... 19
5.11 Short-time over torque test ... 19
5.12 Measurement of no-load axial magnetic pulling force of cone rotor motor 19
5.13 Thermal test (temperature rise) ... 19
5.14 Voltage-rise test and voltage-drop test ... 19
5.15 Casing protection performance test ... 20
5.16 Energy efficiency test ... 20
Appendix A (Normative) The Number of Cycles per Hour, the Number of Starts
per Hour, the Duration of the Load, the Cycle Period, the Mode of Operation,
the Test Load and the Total Use Time of the Motors at Different Working Levels
of the Lifting Mechanism ... 21
Electric Wire Rope Hoists – Part 2: Testing Method
1 Scope
This Part of JB/T 9008 specifies the basic test requirements and the test contents and
methods of each test for electric wire rope hoists.
This Part is applicable to electric wire rope hoists (hereinafter referred to as electric
hoists) that use or lift molten metal in a general environment. The electric hoists that
are used in other environments can be referred to.
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 document.
GB/T 1032-2012 Test Procedures for Three-Phase induction Motors
GB/T 4942.1-2006 Degrees of Protection Provided by the Integral Design of
Rotating Electrical Machined (IP Code) - Classification
GB/T 5972 Cranes - Wire Ropes - Care, Maintenance, Installation, Examination
and Discard
GB/T 9239.1 Mechanical Vibration - Balance Quality Requirements for Rotors in
a Constant (Rigid) State - Part 1: Specification and Verification of Balance
Tolerances
GB/T 9286 Paints and Varnishes - Cross-Cut Test
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 22719.1 Interturn Insulation of Random-Wound Winding for AC Low-Voltage
Electrical Machines - Part 1: Test Methods
GB/T 22719.2 Interturn Insulation of Random-Wound Winding for AC Low-Voltage
Electrical Machines - Part 2: Test Limits
GB/T 30028 Energy Efficiency Test Methods for Electrical Hoists
GB/T 29562.3 Energy Efficiency Test Procedures of Motors for Crane - Part 3:
Conical Rotor 3-Phase Asynchronous Motors
JB/T 9008.1 Electric Wire Rope Hoists - Part 1: Types and Basic Parameter,
Specification
3 Basic Requirements for Test
3.1 In addition to the test methods specified in this Part, other advanced and reliable
test methods are allowed to be adopted.
3.2 The test power supply shall be consistent with the design power supply of the
electric wire rope hoist. The sinusoidal distortion rate of the voltage waveform shall not
exceed 5%; and the difference between the frequency of the test power supply and
the rated frequency shall be within ±1%.
3.3 Measuring instruments and measuring tools shall be qualified and within the validity
period of the verification. The selection of accuracy grade and range shall be able to
meet the technical requirements of the test piece; and the specific requirements are
as follows:
a) The accuracy of the voltmeter shall be no less than Level-0.5;
b) The accuracy of the ammeter shall be no less than Level-0.5;
c) The accuracy of the three-phase wattmeter shall be no less than Level-1;
d) The accuracy of the transformer for measuring instrument shall be no less than
Level-0.2;
e) The reading error of the tachometer is within ±1 r/min; and the accuracy of the
digital tachometer and slip rate measuring instrument shall be no less than 0.1%
± 1 character;
f) The accuracy of the torque measuring instrument (including dynamometer and
sensor) shall be no less than Level-0.5;
g) The accuracy of the dynamometer shall be no lower than Level-1.0;
h) The allowable deviation of the thermometer is ±1°C;
i) The allowable deviation of the test load is ±1%;
j) When the test instrument uses a computer automatic test system, the accuracy
c) Start the lifting mechanism to lower the hook; rotate the drum for two revolutions;
and check whether the wire rope can be discharged from the drum freely.
4.5 Voltage-drop test and voltage-rise test
Before the voltage-drop test, adjust the voltage at the motor terminal to 90% of the
rated voltage; make the rated load start for three times in the air, with a total stroke of
about 2m. And then raise the two-speed electric hoist slowly again, and check whether
the electric hoist starts and operate normally.
Before voltage-rise test, adjust the voltage at the motor terminal to 110% of the rated
voltage; make the rated load start for three times in the air, with the total stroke is about
2 m. And then raise the two-speed electric hoist slowly again, and check whether the
electric hoist starts and operate normally.
4.6 Determining the braking sliding amount
There are many methods to measure the braking sliding amount, two methods are
recommended. When there is an objection, Method-1 shall be used as the arbitration
method.
Method-1: Under the conditions of rated voltage, rated frequency and rated load, use
a reflective laser displacement sensor to continuously detect the position of the load.
When the load drops to a certain position at the rated speed; a stop signal is given;
and the test system marks the load position. After the load is stopped steadily, the test
system marks the end position of the load braking; and the system calculates the
difference between the two, which is the brake sliding amount. Measure three times
continuously and take the average value.
Method-2: Under the conditions of rated voltage, rated frequency and rated load, use
a steel wire rope with a diameter of 1mm. One end is tied to a small mound; and the
other end is connected with a fixed micro switch (with normally-closed contact). The
normally-closed contact is connected to the descending road controlled by a contactor.
The mass of the mound shall be sufficient to make the switch act and cut off the
descending circuit. During the measurement, the mound is placed on the load. When
the load drops to a certain position at the rated speed, the mound is separated from
the load. At this time, the descending circuit is immediately cut off, and the load starts
to slide down immediately. The vertical distance between the mound and the load is
the sliding amount; continuously measure for 3 times, and take the average value.
4.7 Measurement of the lifting and descending speed
Under the conditions of rated voltage, rated frequency and rated load, measure the
lifting and lowering speeds.
Lifting speed: When the lifting distance exceeds 0.5 m, use a stopwatch to measure
̅pA – average noise on the measured surface, in dB(A);
N – the total number of measuring points;
LpAi – noise measured at the ith point, in dB(A);
K1i – corrected value of the background noise at the ith point, in dB(A).
NOTE 1: When the change range of the value (LpAi - K1i) does not exceed 5.0 dB(A), the
arithmetic average can be used to replace the energy average; at this time, ,
its calculation error is no greater than 0.7 dB(A).
NOTE 2: When the difference between the actual measured noise and the background noise
is less than 3 dB(A), the measured value is invalid.
4.9 Current and voltage test
Under the conditions of rated voltage, rated frequency and rated load, test and record
the current and voltage during lifting.
4.10 Safety brake test
Under the conditions of rated voltage and rated frequency, start the working brake of
the electric hoist. After the electric hoist lifts the rated load to a suitable height,
disconnect the lifting power supply and check whether the safety brake can reliably
support the rated load.
4.11 Static load test
Under the conditions of rated voltage and rated frequency, the electric hoist lifts the
rated load to a height of 100 mm~200 mm from the ground; and then gradually, slowly
and steadily loads to 1.25 times the rated load, and the hanging time shall be no less
than 10 min.
After unloading, visually inspect whether there are cracks, permanent deformation,
paint peeling, damage, loose connections, and other abnormal phenomena for all parts.
4.12 Dynamic load test
Under the conditions of rated voltage, rated frequency and test load are 1.1 times the
rated load, the hoisting mechanism shall operate continuously in accordance with the
cycle period of Appendix A corresponding to the design reference working level, and
shall be no less than 30 min.
For the electric hoist with operating mechanism, the electric hoist runs continuously for
10 cycles; and the single-way running distance of each cycle shall be no less than 2
m.
After unloading, visually inspect whether there are cracks, permanent deformation,
paint peeling, damage, loose connections, and other abnormal phenomena for all parts.
NOTE: For electric hoist equipped with load lifting limiter, when carrying out static load test and
dynamic load test, the load lifting limiter shall be unprotected before the test.
4.13 Function test of load lifting limiter
Under the conditions of rated voltage, rated frequency and rated load, check whether
the electric hoist can lift normally.
Increase the actual lifting load to 110% of the rated lifting load; directly lift the load; and
check whether the load lifting limiter can cut off the lifting power supply and stop lifting.
At this time, measure the lifting distance of the load and check whether the lifting
mechanism can do the descending movement.
4.14 Operating mechanism test
4.14.1 Operating test
Under the rated voltage and rated frequency, the electric hoist shall reciprocate on the
track for no less than 2 times, and the stroke shall not be less than 2m each time when
there is no load and under rated load.
4.14.2 Determining the operating speed
Under the conditions of rated voltage, rated frequency and rated load, the test shall be
carried out on the track. The track shall be flat, and the static deflection in the middle
of the track shall be less than L/1000 (L - the distance between the fulcrums of the
track).
During the test, mark two points on the track that are no less than 2 m apart. When the
electric hoist operates normally to one mark, it will start timing; and when it operates
to the other mark, it will stop timing. The operating speed is calculated by calculation,
and it is repeatedly measured for four times and take the average value.
4.14.3 Climbing test of operating mechanism
Under the conditions of rated voltage, rated frequency and rated load, the electric hoist
will reciprocate three times on a track with a slope of 1/200, each one-way stroke is at
least 2 m, and check whether it can work normally.
If the test is performed on a horizontal track, a force shall be applied in the opposite
direction of operation, the magnitude of which is equal to 1/200 of the sum of the mass
of the hoist and the rated load.
2 – lowest position for the descending of the test load.
Figure 2
4.17.3 Under the rated voltage and rated frequency of the hoisting mechanism, the
service life test shall be carried out according to the working cycle and total service
time of appendix A as per the working level and test load determined by the test plan.
In the single-speed electric hoist test, the load shall fall to the ground once every twelve
cycles; in the two-speed electric hoist test, the load should fall to the ground once every
four cycles; after every sixteen cycles, the load shall be lifted directly after the load has
fallen to the ground. During the test, the change in load duration caused by the falling
to the ground of the load is negligible.
If the motor has reached a thermally stable state during the test, the motor can be
tested through improving the load duration and the number of starts under thermally
stable conditions through external cooling, so that achieve the purpose of shortening
the test time.
4.17.4 During the test, perform normal maintenance according to the requirements of
the instruction manual, and make the following inspection records:
a) When operating for 1h, test and record the noise and brake sliding amount,
resp...