1、BRITISH STANDARD BS 4819-2: 1989 Resistance welding water-cooled transformers of the press-package and portable types Part 2: Specification for portable transformers UDC 621.314.21:621.791.763BS4819-2:1989 This British Standard, having been prepared under the directionof the Welding Standards Policy
2、 Committee, waspublished under the authorityof the Board ofBSIandcomes into effect on 29September1989 BSI 11-1999 First published as BS4819July1972 First revision as BS4819-2 The following BSI references relate to the work on this standard: Committee reference WEE/26 Draft for comment 88/70774 DC IS
3、BN 0 580 17521 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Welding Standards Policy Committee (WEE/-) to Technical Committee WEE/26, upon which the following bodies were represented: Association of Supervisory and Executive Enginee
4、rs British Non-ferrous Metals Federation British Steel Industry British Telecommunications plc Copper Development Association Electricity Supply Industry in England and Wales Health and Safety Executive Society of British Aerospace Companies Limited Society of Motor Manufacturers and Traders Limited
5、 Welding Institute Welding Manufacturers Association (BEAMA Ltd.) Coopted members Amendments issued since publication Amd. No. Date of issue CommentsBS4819-2:1989 BSI 11-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Service conditions 1 3.1 Ge
6、neral 1 3.2 Altitude 1 3.3 Temperature of the cooling media 1 4 Design and construction 1 4.1 General 1 4.2 Rating 1 4.3 Primary circuit 2 4.4 Secondary circuit 2 4.5 Electromechanical stress 2 4.6 High voltage 2 4.7 Insulation resistance 2 4.8 Protection against ingress of dust and liquids 2 5 Test
7、s 2 5.1 Type tests 2 5.2 Routine tests 3 6 Testing 3 6.1 Temperature rise at thermal rating 3 6.2 Short circuit secondary current using standard load 3 6.3 Electromechanical stress 3 6.4 No-load primary current 3 6.5 Open circuit secondary voltage 3 6.6 Water pressure 4 6.7 Water flow 4 6.8 High vol
8、tage 4 6.9 Insulation resistance 4 6.10 Protection against dust and ingress of liquids 4 7 Measurement of temperature 5 7.1 Temperature test conditions 5 7.2 Winding temperature at end of test 5 8 Safety 6 9 Nameplate 6 Appendix A Relationship between transformer operating dutycycleandinputkVA on an
9、y specified tapping 7 Appendix B Calculation of permissible duty cycle from the thermal rating 8 Figure 1 Secondary standard resistance load for portable weldingtransformer 4 Figure 2 Transformer operating duty cycle and input kVA 7 Table 1 Limits of temperature rise 2 Table 2 Maximum values for no-
10、load power (S o ) and no-load current (I 10 ) 5 Publications referred to Inside back coverBS4819-2:1989 ii BSI 11-1999 Foreword This revision of BS4819 has been prepared under the direction of the Welding Standards Policy Committee. It forms one of a series of standards dealing with resistance weldi
11、ng equipment. It supersedes BS4819:1972, which is withdrawn. In this edition BS4819 has been divided into two Parts dealing with press package transformers and with portable transformers respectively. This was done so that subsequent revisions could be made to one part without affecting the other, p
12、articularly in view of the international input into the requirements on press package transformers. This Part has been prepared to meet the needs of manufacturers and users for standardizing the dimensional requirements and method of rating transformers for portable spot welding guns. A British Stan
13、dard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover,
14、 an inside front cover, pages i and ii, pages1 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4819-2:1989 BSI 11-1999 1 1 Scope This P
15、art of BS4819 specifies the requirements, methods of test, service conditions and rating of single-phase, mains frequency resistance welding water-cooled transformers of the portable type having a primary voltage of660V or less. NOTEThe titles of the publications referred to in this standard are lis
16、ted on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions apply. For other relevant terms the definitions in BS499-1 apply. 2.1 duty cycle the time that the load is applied, expressed as a percentage of the integrating period NOTE 1The terms “dut
17、y factor” and “duty cycle” are synonymous. NOTE 2In this standard the word “load” should be considered in a restricted manner. It refers to a constant electrical load without periods of pre-heat, post-heat and slope-control. 2.2 integrating period the sum of one load period and one no-load period 2.
18、3 thermal rating the maximum electrical input, in kVA, at a duty cycle of50% with a1min integrating period, without exceeding the specified temperature NOTEFor the thermal rating at other duty cycles, seeAppendix A. 2.4 portable transformer a transportable water-cooled transformer consisting of a pr
19、imary and secondary winding, electrically isolated from each other, used to supply welding current to, but remote from, a portable spot welding gun or guns 2.5 rated secondary current the current, calculated by dividing the thermal rating by the maximum open circuit secondary voltage, obtainable by
20、series connection of the secondary windings 2.6 rated primary current the current calculated by dividing the thermal rating by the rated primary voltage 2.7 rated primary voltage the voltage applied directly to the transformer primary winding NOTEThis voltage is not necessarily the same as the suppl
21、y voltage. 3 Service conditions 3.1 General This British Standard is applicable when transformers are used under the conditions given in3.2 and3.3. 3.2 Altitude The height above sea level at which the transformer is intended to work in ordinary service shall not exceed1000m. 3.3 Temperature of the c
22、ooling media The temperature of the cooling water flowing shall be less than30 C at the inlet and the ambient air temperature shall be less than40 C. 4 Design and construction 4.1 General The transformer shall be of the double wound type, the primary winding being electrically isolated from the seco
23、ndary winding by means of reinforced insulation in accordance with BS2754. Live parts shall be so insulated or supported that they do not come into electrical contact with one another or with any earthing conductor or metal parts exposed to personal contact. Live parts shall be so enclosed that no p
24、erson can inadvertently come into contact with any live part that can normally attain a potential in excess of55V above earth potential. Covers for the guarding of live parts shall be effectively secured in position in such a way that their removal requires the use of a tool. All exposed conductive
25、parts, with the exception of the secondary winding, shall have a common electrical connection for earthing purposes. 4.2 Rating 4.2.1 The thermal rating shall be not less than that stated on the nameplate. The standard rating shall be75,100,150 or200kVA at the highest secondary voltage. The maximum
26、observable temperature rise used to determine the thermal rating shall not exceed that given inTable 1.BS4819-2:1989 2 BSI 11-1999 Table 1 Limits of temperature rise 4.2.2 The transformer shall be capable of supplying rated secondary current at50% duty cycle without exceeding the observable limiting
27、 temperature rise. On taps other than that producing the maximum secondary voltage, a reduction in the current rating in direct proportion to the open circuit secondary voltage shall be permitted. The temperature rise of the tap switch or tapping links shall not exceed the value given inTable 1. 4.3
28、 Primary circuit 4.3.1 If the transformer is provided with a primary tapping switch or link, the tappings shall be numbered progressively with the highest secondary voltage being associated with the highest numbered tap. 4.3.2 The no-load primary current at rated primary voltage shall be as specifie
29、d in6.4. 4.4 Secondary circuit 4.4.1 The secondary circuit shall consist of two separate windings, that can be connected in series or in parallel as required. The maximum open circuit secondary voltage at rated primary voltage shall be within the following limits: a) 75 kVA transformers: 16 V to 19
30、V b) 100 kVA transformers: 19 V to 22 V c) 150 kVA transformers: 22 V to 25 V d) 200 kVA transformers: 25 V to 28 V 4.4.2 The open circuit secondary voltage on the lowest tap setting shall be not more than75% of that attainable on the highest setting. 4.4.3 The secondary standard load current, when
31、measured in accordance with6.2, shall be not less than: a) 75 kVA transformers: 18000 A b) 100 kVA transformers: 20500 A c) 150 kVA transformers: 25500 A d) 200 kVA transformers: 29000 A 4.4.4 The secondary sections shall have a cooling system designed to operate with inlet water at a temperature no
32、t exceeding30 C and a rate of flow of4.5L/min for transformers up to and including150kVA and8L/min for200kVA transformers, and shall withstand the water pressure test specified in6.6 and the water flow test specified in6.7. 4.5 Electromechanical stress The transformer shall withstand the test specif
33、ied in6.3. 4.6 High voltage The transformer shall withstand the high voltage proof test specified in6.8. 4.7 Insulation resistance The transformer shall have an insulation resistance of at least20M7 when new. 4.8 Protection against ingress of dust and liquids The transformer shall have a minimum deg
34、ree of protection corresponding to the designation IP53, as specified in BS5490, when tested in accordance with6.10. 5 Tests 5.1 Type tests The type tests shall be for the purpose of verifying the essential performance characteristics of the transformer and normally made only once to establish desig
35、n characteristics. Type tests shall include the following: a) temperature rise at thermal rating (see6.1); b) short circuit secondary current using standard load (see6.2); c) electromechanical stress (see6.3); d) no-load primary current (see6.4); e) open circuit secondary voltage (see6.5); f) water
36、pressure (see6.6); g) water flow (see6.7); h) high voltage (see6.8); i) insulation resistance (see6.9); Part Method of determination Maximum temperature rise for insulation classifications A E B F H C C C C C Primary winding Resistance 70 85 95 115 140 Embedded detector 70 85 95 120 145 Secondary wi
37、nding Thermometer 65 80 90 110 130 Embedded detector 70 85 95 120 145BS4819-2:1989 BSI 11-1999 3 j) measurement of temperature (clause7); k) protection against ingress of dust and liquids (see6.10). 5.2 Routine tests The routine tests shall be for the purpose of detecting equipment with manufacturin
38、g defects. Routine tests shall include testsd) toi) of5.1 inclusive. 6 Testing 6.1 Temperature rise at thermal rating The flow of cooling water during the test shall be4.5L/min for transformers up to and including150kVA and8L/min for200kVA transformers. With the tap switch or links set so as to give
39、 the highest secondary voltage, connect the secondary windings in series. Test the transformer, at rated primary voltage and rated primary current for a50% duty cycle based on a1min integrating period. Alternatively, provided that the maximum allowable temperature is not exceeded, test the transform
40、er at reduced primary voltage at an equivalent duty cycle, using the “Pf is a constant” rule (seeAppendix B). Continue the test until either: a) the temperature rise attains a steady state value; or b) data are available to show that the temperature would not exceed the requirements ofTable 1 if the
41、 test were prolonged until a steady state value were obtained. The temperature rise above the ambient so determined shall not exceed the appropriate value specified inTable 1. 6.2 Short circuit secondary current using standard load 6.2.1 The secondary standard resistance load shall be a wrought high
42、 conductivity copper bar, as shown inFigure 1, bolted to the terminals. This standard load shall be maintained between15 C and25 C to keep its resistance relatively constant. 6.2.2 Determine the short circuit secondary current using the standard load, with the two secondary windings connected in ser
43、ies. Take measurements with that part of the primary winding in circuit for the test at the maximum temperature attained during the thermal rating test. Apply a test voltage of the value required to cause a current at least equal to the rated primary current upon the transformer primary winding, wit
44、h the tap switch or tapping links set to the tap that produces the highest secondary voltage. Calculate the secondary standard load current from the following formula: The short circuit secondary current using the standard load calculated above shall be not less than the appropriate value given in4.
45、4.3. 6.3 Electromechanical stress 6.3.1 Connect the transformer to the rated supply voltage with the transformer tap switch on the tap that produces the highest secondary voltage and the secondary loaded so as to allow6times the rated primary current to flow in the primary circuit. Subject the trans
46、former to the above load for10min at a1.5% duty cycle. 6.3.2 The transformer shall withstand the test specified in6.3.1 without mechanical damage. 6.4 No-load primary current The no-load primary current, at rated primary voltage, shall not exceed the values given inTable 2. 6.5 Open circuit secondar
47、y voltage The open circuit secondary voltage shall be within 2.5% of the declared value at each tap setting at rated primary voltage. Rated primary voltage () 2 (Measured primary current at test voltage) Text voltage ()(Maximum no-load secondary voltage) -BS4819-2:1989 4 BSI 11-1999 6.6 Water pressu
48、re 6.6.1 Fill, close and pressurize the cooling system to7 bar 1) . Seal. 6.6.2 The pressure shall be held, without failure, for10min. 6.7 Water flow 6.7.1 Measure the inlet pressure required to ensure a flow of cooling water of4.5L/min or8L/min, as appropriate (see4.4.4). Measure the flow in both d
49、irections. 6.7.2 To maintain this flow the highest pressure required in either direction shall not exceed0.5bar 1) . 6.8 High voltage 6.8.1 General. The high voltage test shall be carried out within1h of the completion of the water tests specified in6.6 and6.7. The high voltage test shall be carried out with a single phase alternating voltage of sinusoidal form and at rated supply frequency. The high voltage
