GB 28736-2019 PDF in English
GB 28736-2019 (GB28736-2019) PDF English
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| GB 28736-2019 | English | 130 |
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Minimum allowable values of energy efficiency and energy efficiency grades for welding machines
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| GB 28736-2012 | English | 90 |
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Minimum allowable values of energy efficiency and energy efficiency grades for arc welding machines
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Standards related to (historical): GB 28736-2019
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GB 28736-2019: PDF in English GB 28736-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.010
F 01
Replacing GB 28736-2012
Minimum allowable values of energy efficiency and
energy efficiency grades for welding machine
ISSUED ON: DECEMBER 31, 2019
IMPLEMENTED ON: JULY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 Energy efficiency grades of welding machine ... 5
5 Technical requirements ... 6
6 Test methods ... 9
Minimum allowable values of energy efficiency and
energy efficiency grades for welding machine
1 Scope
This Standard specifies the energy efficiency grades, minimum allowable
values of energy efficiency and test methods for arc welding machine and
resistance welding machine.
This Standard is applicable to the arc welding machine and resistance welding
machine that are designed for industrial and professional use, not exceeding
the voltage specified in GB/T 156.
The resistance welding machine to which this Standard applies specifically
refers to the resistance welding transformer which is finally installed with the
frame, the input circuit and the secondary circuit.
This Standard is not applicable to AC TIG arc welding machine, AC and DC TIG
arc welding machine, power frequency secondary rectification resistance
welding machine, seam welding machine, resistance butt welding machine,
flash butt welding machine, energy storage resistance welding machine,
inverter AC resistance welding machine, separately-sold resistance welding
transformer and mechanical equipment driven welding machine.
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/T 156, Standard Voltages
GB/T 2900.22, Electrotechnical terminology - Electric welding machine
GB/T 8118, The general specification for arc welding machines
GB/T 8366, Resistance welding - Resistance welding equipment -
Mechanical and electrical requirements
GB/T 14549-1993, Quality of Electric Energy Supply - Harmonics in Public
Supply Network
GB 15578, Safety requirements for resistance welding machine
GB/T 15579.1, Arc welding equipment - Part 13: Welding clamps
GB/T 25301, Resistance welding equipment - General specifications
applicable to all transformers
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T
2900.22, GB/T 8118, GB/T 15579.1, GB/T 8366, GB 15578, and GB/T 25301
as well as the followings apply.
3.1 minimum allowable values of energy efficiency for welding machines
The maximum guaranteed value of allowable efficiency of an arc welding
machine in the rated state, the maximum limit of short circuit loss allowed by a
resistance welding machine in the rated gear, under standard-specified test
conditions.
3.2 no-load loss for resistance welding machine
The active power when the secondary winding of a resistance welding machine
(where applicable, including a rectifier) is in an open circuit, and at the rated
gear position, the rated voltage of the rated frequency is applied to the primary
winding of the resistance welding machine and input to the resistance welding
machine.
3.3 short circuit loss for resistance welding machine
The active power input to a resistance welding machine when the secondary
winding of the resistance welding machine (where applicable, including a
rectifier) is in the best short circuit condition, and at the rated gear position, an
appropriate voltage at the rated frequency is applied to the primary winding of
the resistance welding machine, when the current flowing through the primary
winding is the continuous input current I1P of the resistance welding machine.
4 Energy efficiency grades of welding machine
The energy efficiency grade of welding machine is divided into 3 grades, where
grade 1 is the highest energy efficiency. The energy efficiency indicators of arc
welding machines at all grades shall comply with corresponding provisions in
Table 1 ~ Table 6. The energy efficiency indicators of resistance welding
machines at all grades shall comply with corresponding provisions in Table 7 ~
Table 10. If the nominal load duration of resistance welding machine is 50%,
temperature of 10°C ~ 40°C. Welding machines that use liquid cooling shall be
tested under the liquid cooling conditions specified by the manufacturer. The
energy efficiency of a welding machine shall be measured under the following
conditions:
a) Achieve thermal equilibrium under rated operating conditions;
b) An arc welding machine shall be adjusted to the rated maximum welding
current;
c) A resistance welding machine is at the rated capacity gear corresponding
to 50% load duration;
d) When the load duration is below 100%, at the midpoint of the load time;
e) Auxiliary equipment (such as wire feeder) is in no-load operation.
6.2 Measuring device
The measuring device shall meet the following requirements:
a) The measuring device shall meet the relevant standards and shall be
calibrated or verified at a prescribed interval.
b) The accuracy or precision of the electrical measuring device is grade 0.5
(± 0.5% of full scale), and the temperature measuring instrument is ±2K.
c) The measuring device shall meet the measurement requirements of the
measured parameters. Select a correct measurement device according to
the voltage and/or current waveform. The influence of at least the following
factors on the measurement results shall be excluded:
● Harmonics of input current of inverter welding machine;
● Frequency of inverter welding machine;
● Non-sinusoidal and/or non-periodic voltage and/or current;
● Large ripple factor DC voltage and/or current.
d) The measuring device of input power shall be a direct measuring device.
e) The load used to measure the arc welding machine shall be an actual non-
inductive constant resistance load with a power factor of not less than 0.99.
6.3 Power supply
6.3.1 Classification and parameters of power supply mode
Where,
Rs - Power supply impedance, in ohms (Ω);
U1no-load - Power input voltage when the welding machine is no-load;
U1load - Power input voltage when welding machine is load;
I1load - Input current of the welding machine under load;
I1no-load - Input current of the welding machine at no load.
When determining the impedance of the power supply, ensure that the
input voltage difference between no-load and load is more than 1%, and
all voltage regulation or voltage stabilization functions of the power supply
shall be turned off.
c) The input voltage of the welding machine shall be its nominal rated input
voltage value.
d) The input power frequency of the welding machine shall be the rated
frequency of its nominal input power.
e) The allowable unbalance of three-phase voltage shall not be greater than
±1.5%.
6.3.3 Variable frequency power supply
When measuring the energy efficiency of an inverter resistance welding
machine, it requires variable frequency power supply or power supply by
variable frequency controller of resistance welding machine. In addition to self-
power supply by inverter controller that supports the resistance welding
machine, the inverter power supply to the inverter resistance welding machine
shall meet the following requirements:
a) When the frequency is within ±1% of nominal frequency of resistance
welding machine, the voltage waveform shall be a full-rectangular
rectangular wave with alternating polarities with a duty cycle of not less
than 85%. The rise and fall times of rectangular waves must not exceed
1% of the cycle. The difference between the maximum value and the
minimum value of the rectangular wave amplitude must not exceed 5% of
the sum of the maximum and minimum values of the rectangular wave
amplitude;
U1no-load – U1load
I1load – I1no-load
b) When measuring the no-load current and no-load loss of the resistance
welding machine, it shall be able to provide the nominal rated input voltage
value at the nominal frequency of the resistance welding machine;
c) When measuring the short-circuit loss of the resistance welding machine,
it shall be able to provide continuous input current (I1P) at nominal
frequency of resistance welding machine.
6.4 Test site layout
6.4.1 Welding machine layout
When conducting the energy efficiency test on welding machines, the test site
layout of welding machines shall meet the following requirements:
a) A welding machine and its auxiliary equipment shall be arranged according
to the actual conditions of use;
b) In order to keep a welding machine in normal ventilation and heat
exchange, in addition to the support surface, there must be no shelter or
strong air convection within 1m from the periphery of the welding machine;
c) There must be no magnetically permeable material that affects the test
accuracy within 1m from the periphery of a welding machine;
d) When measuring the no-load current and no-load loss of a resistance
welding machine, the output end of the resistance welding machine is
open-circuit state;
e) When measuring the short-circuit loss of a resistance welding machine,
the output of the resistance welding machine is the best short-circuit state.
6.4.2 Input cable layout
When conducting the energy efficiency test on welding machines, the input
cable layout shall meet the following requirements:
a) Minimize the inductance due to input cable layout;
b) The input cable shall be folded into a harness with a length of no more
than 40cm.
6.4.3 Measuring device layout
When conducting the energy efficiency test on welding machines, the
measuring device layout shall meet the following requirements:
a) All input currents fed into an arc welding machine or resistance welding
machine can be measured;
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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