Thursday, October 24, 2013

Methods of explosion protection for electrical equipment

METHODS OF EXPLOSION PROTECTION

Method                                                                                               Type of Protection

Designed to prevent any means of ignition arising            Ex e Increased Safety

Ex n or Ex N Non Sparking

Designed to limit the ignition energy of the circuit            Ex I Intrinsic Safety

Designed to prevent the flammable mixture reaching    Ex m Encapsulation

a means of ignition                                                                          Ex p Pressurisation

Ex o Oil Immersion

Ex nR or Ex N Restricted Breathing

Designed to prevent any ignition from spreading              Ex d Flameproof Enclosure

Ex q Powder Filling

 

Friday, October 18, 2013

Minimum terminal capacity for copper protective conductors (PE, PEN)

CROSS-SECTIONAL AREA OF PHASE CONDUCTORS S
MM2
MINIMUM CROSS-SECTIONAL AREA OF THE CORRESPONDING PROTECTIVE CONDUCTOR (PE, PEN) SPA
MM2
S ≤ 16
S
16 < S ≤ 35
16
35 < S ≤ 400
S/2
400 < S ≤ 800
200
800 < S
S/4
a Current in the neutral may be influenced where there are significant harmonics in the load.
Minimum terminal capacity for copper protective conductors (PE, PEN)
Source: IEC 61439-1 2011 Table 5

Friday, October 11, 2013

Guide to migration from IEC 60439 to IEC 61439 (XL3 Confugurable Assemblies IEC 60439 >>> IEC 61439)

This document only deals with  distribution enclosures for advanced users (authorised persons), i.e. parts 1 and 2 of the new standard. Part 3 of standard IEC 61439 discusses DBO (Distribution Boards intended to be operated by Ordinary persons) only up to 250 A. One of the new features of this standard is that the table in appendix D (checking the design) covered laterin this document does not apply in 61439-3.

In addition in its new version, standard 61439-3 takes account of domestic normative references.

 

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Saturday, September 14, 2013

Measurement of the insulation resistance

- the insulation resistance must be measured with amegohmmeter (external or with standalone source) at

a minimum voltage of 500 VDC

- the assembly being tested must be turned off and there must be no receiver devices connected

- all the breaking devices must be in position i (on)

- the voltage is applied between each circuit and the exposed conductive part

- it is possible to link all the poles: phases and neutral,except in tnC layout in which the pen conductor is considered to be linked to the exposed conductive part

of the assembly.Devices (measurement windings, instruments) which would not withstand the test voltage must have their supply terminals short-circuited.

the measurement conditions can influence the results obtained. measurements should not be carried out temperatures below dewpoint (condensation will

dampen the surfaces).

the insulation resistance decreases with the temperature.if repeated measurements have to be taken,the environmental conditions must be recorded. the period for which the voltage is applied also has a major influence, and measurement can be considered to consist of three sequences. at the start of measurement, the device charges the capacitor which represents the installation in relation to earth and the leakage current is at its highest.

 

LEGRAND POWER GUIDE

Friday, September 13, 2013

Automation Solution guide 2008 (Schneider electric)

Automation Solution guide 2008 (Schneider electric)

 

1 Automation solution guide 8

1.1 Introduction 10

1.2 The automation equipment 10

1.3 Automation architectures 12

1.4 Architecture definition 14

1.5 Choice of automated equipment 17

2 Electrical power supply 28

2.1 Introduction 30

2.2 Power supply to machinery 30

2.3 Standards and conventions 30

2.4 Power supply functions 32

2.5 Power supply to the control circuit 33

3 Motors and loads 36

3.1 Three phase asynchronous motors 38

3.2 Single-phase motors 42

3.3 Synchronous motors 43

3.4 Direct current motors commonly named DC motors 45

3.5 Operating asynchronous motors 47

3.6 Electric motor comparison 50

3.7 Types of loads 51

3.8 Valves and electric jacks 56

4 Starting and protection of motors 60

4.1 Asynchronous motor starting systems 62

4.2 Electrical braking of 3-phase asynchronous motors 69

4.3 Multifunction motor starter units 74

4.4 Motors protection 76

4.5 Motor losses and heating 77

4.6 Causes of faults and their effects 77

4.7 Protection functions 83

5 Motor starter units 82

5.1 Forward 84

5.2 The basic functions of motor starter units 84

5.3 Constitution and operation of contactor 95

5.4 Choosing a contactor 97

5.5 Motor starter and coordination 98

5.6 Advanced starter 103

5.7 Speed controllers 105

5.8 Structure and components of starters and electronic speed controllers 109

5.9 Power components 109

5.10 Controller – regulator for DC motors 113

5.11 AC drives for asynchronous motors 115

5.12 Voltage controller for asynchronous motors 121

5.13 Synchronous motor-speed controller 122

5.14 Stepper motor controllers 123

5.15 Additional functions of speed controllers 124

5.16 Speed controllers and energy assessment 126

5.17 Speed controllers and savings in power and maintenance 128

5.18 Choice table for motor starters 129

6 Data acquisition: detection 132

6.1 Introduction 134

6.2 Electromechanical limit switches 135

6.3 Inductive proximity detectors 136

6.4 Capacitive proximity detectors 138

6.5 Photoelectric detectors 140

6.6 Ultrasonic detectors 142

6.7 RFID -Radio Frequency IDentification-detection 144

6.8 Vision 147

6.9 Optical encoders 151

6.10 Pressure switches and vacuum switches 156

6.11 Conclusion 159

6.12 Technology selection guide 160

7 Personnal and machines safety 162

7.1 Introduction 164

7.2 Safety scope and definition 164

7.3 Industrial accidents 166

7.4 European legislation 178

7.5 Standard to be applied according design selected for the machine control 170

7.6 Standard EN/ISO 13849-1 Machinery safety - Safety-related parts 172

7.7 Standard EN 62021 Machinery safety - Functional safety 176

7.8 Certification and marking 180

7.9 Consideration of hazardous atmospheres 182

8 Human-machine interface 186

8.1 Human-machine interface setup 188

8.2 User needs specification 190

8.3 Choosing a solution 192

8.4 Discrete control and indicator units 194

8.5 Schneider Electric Discrete Control and Indicator Unit offer 197

8.6 Graphis screen display and terminal 198

8.7 Industrial and supervision PCs 200

8.8 The human/machine dialogue and supervision software 201

8.9 Control panels incorporated in the products 203

8.10 Conclusion 204

9 Industrial networks 206

9.1 Introduction 208

9.2 History 208

9.3 Market requirements and solutions 209

9.4 Network technologies 211

9.5 Networks recommended by Schneider Electric 213

9.6 Ethernet TCP/IP 214

9.7 Web services and Transparent Ready 217

9.8 Canopen bus 224

9.9 Ethernet and CANopen synergy 232

9.10 AS-Interface (AS-I) Bus 232

9.11 Conclusion 239

10 Data treatment and software 240

10.1 Définition 242

10.2 Introduction 242

10.3 Programming, configuration and languages 243

10.4 Application categories 244

10.5 UAG: Application generators 258

10.6 Definition of the main abbreviations used 262

11 Equipment manufacturing 264

11.1 Equipment design 266

11.2 Choice of supplier 267

11.3 Drafting diagrams and programs 268

11.4 Programming methodology 270

11.5 Choice of technology 271

11.6 Equipment design 272

11.7 Building an equipment 273

11.8 Mounting 276

11.9 Device fitting tools 277

11.10 Platform tests 278

11.11 Equipment commissioning 281

11.12 Equipment maintenance 283

12 Eco-design 286

12.1 Foreword 288

12.2 Concepts and main directives 289

12.3 Standards 290

12.4 Eco-design 291

12.5 Lifecycle 291

12.6 Main rules of eco-design 292

12.7 Conclusion 295

12.8 Applications 295

M Memorandum 298

M.1 Quantities and units of measurement 300

M.2 Average full-load currents of asynchronous squirrel cage motors 301

M.3 Electrical formulae 302

M.4 Calculation of starting resistances 304

M.5 Mechanical formulae 305

M.6 Fundamental formulae 306

M.7 Neutral connections 307

M.8 Driving machines 308

M.9 Conversion tables for standard units 310

7

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