standards and guidelines for communication sites - Radio And ...

More documents

Recommendations

Info

BATTERY SYSTEMS CHAPTER 6: POWER SOURCES 6.7.4 BATTERY SIZING Battery sizing can be straightforward or fairly complex, depending on the characteristics of the load being backed up. Stationary batteries (those used for fixed locations) are rated in Amp-Hours (AH). An 8-hour duration represents a rated amperage. The amp hour rating of stationary batteries is generally stated as the number of amps a battery can deliver for an 8-hour period. For example, 100 A for 8 hours is a 800 AH battery. If durations of other than 8 hours are desired, a correction factor must be applied. Table8-1 provides the correction factors for several durations. Note that new batteries do not deliver 100% of their rating. It takes several charge/discharge cycles to bring a battery plant to full capacity. Also, as a battery continues to age its capacity gradually falls to 80% of its initial rating, at which point it is considered to be at end of life. These characteristics should be considered when choosing batteries. TABLE 6-5 BATTERY RATING CORRECTION FACTORS The DC load for most digital systems can be assumed to be steady-state, as it does not vary (even during busy times). Multiply the load by the back-up duration, and apply the correction factor, if necessary. For example, given a load of 32 amps and a back-up duration of 4 hours, multiply the load (32) by the duration in hours (4) and the correction factor of 1.157. This means that a battery with at least a 148 amp hour rating will be required for this application. To calculate battery size, the power required and duration of each change must be known. Graph out the entire discharge profile. When the discharge profile is graphed, divide the discharge into blocks based on duration. 6.7.5 BATTERY RATING 1 Hour 2 Hours 4 Hours 6 Hours 8 Hours 1.763 1.378 1.157 1.061 1.0 Batteries shall be accurately sized to ensure they will maintain proper voltage for the required time duration. Use worst-case scenarios with respect to age/deterioration, lowest temperature, expected load, and the availability of alternate power generators. 6.7.6 MULTIPLE BATTERY STRINGS General practice stipulates that battery types, ratings, and service life shall not be mixed among a rack. If a site is expanded, then all fresh, similar batteries shall be installed and the old batteries removed. A mixture of batteries results in unequal current distribution and charging, and the probability of ongoing power system problems as batteries of different ages fail. 6-32 68P81089E50-B 9/1/05
STANDARDS AND GUIDELINES FOR COMMUNICATION SITES BATTERY SYSTEMS Floor loading, growth, and system load are a few of the factors that determine the number of strings of batteries required. All battery backup systems require maintenance. Some of the maintenance operations require the batteries to be off-line. Because there is no way to predict a short duration power interruption, a minimum of two strings of batteries is strongly recommended. This will ensure some amount of battery backup should an interruption occur during battery maintenance. Too many strings of batteries also presents a problem. Should a fault occur in one cell in one string of batteries, diagnosing and locating the fault becomes more difficult as the number of strings increases. To protect the battery plant from a catastrophic failure of a single string of batteries, overcurrent protection is necessary for each individual string in the plant. The sizing of this protection should be as follows: System amp capacity/Number of battery strings -1 = Required protection Manufacturer recommendations for the maximum number of strings varies widely. Motorola recommends that the power system be initially designed for a minimum of two strings and a maximum of six strings of batteries when the system is fully implemented. This will allow some margin for excess growth should the system exceed the anticipated load of a fully implemented system. 6.7.7 BATTERY CHARGING Batteries that have been discharged to a state below full charge must be fully recharged within 24 hours. During this process considerable charging current may flow and flooded cell batteries will give off a higher level of gas than during normal float charge. A float charge must be maintained to keep the battery in a fully charged state. Over or under charging of batteries will cause an increased need for battery maintenance and may greatly shorten the service life of the battery. It is important that the charging system is properly adjusted per the manufacturer's specifications. Overcharging and undercharging alarms shall be installed to ensure that battery charging problems are detected quickly. 6.7.8 BATTERY TEMPERATURE REQUIREMENTS Battery performance and service life are significantly affected by operating temperature. For full-rated performance and maximum service life, the battery temperature should be maintained close to 24° C (75° F). The battery operating time is reduced as the temperature falls; conversely, the operating time is increased as the temperature rises. However, when batteries are subjected to elevated temperatures the service life of the battery is reduced. Reference temperature is often overlooked in rating batteries. Battery manufacturers typically use 22.2° C (72° F) as the reference temperature. A battery operated at 0° C (32° F) produces 30% capacity, but lasts for 130% or more of the rated life. Conversely, a battery operated at 38° C (100° F) produces 130% battery capacity, but may last less than 1 year. NOTE: If building codes do not allow batteries within the same compartment as the climatized radio equipment enclosure, outdoor battery pedestals may have to be protected from direct sunlight or elevated to prevent their burial in snow during winter (where applicable). 68P81089E50-B 9/1/05 6-33
Page 1 and 2:
© 2005 MOTOROLA, INC. ALL RIGHTS R
Page 3 and 4:
TABLE OF CONTENTS Chapter 1. Introd
Page 5 and 6:
STANDARDS AND GUIDELINES FOR COMMUN
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
CHAPTER 1 INTRODUCTION 1 This manua
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
CHAPTER 2 SITE DESIGN AND DEVELOPME
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
CHAPTER 3 COMMUNICATION SITE BUILDI
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
CHAPTER 4 EXTERNAL GROUNDING (EARTH
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
CHAPTER 5 INTERNAL GROUNDING (EARTH
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248: STANDARDS AND GUIDELINES FOR COMMUN
Page 267 and 268: CHAPTER 6 POWER SOURCES 6 6.1 LOCKO
Page 297: STANDARDS AND GUIDELINES FOR COMMUN
Page 311 and 312: CHAPTER 7 SURGE PROTECTIVE DEVICES
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
CHAPTER 8 MINIMIZING SITE INTERFERE
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
CHAPTER 9 EQUIPMENT INSTALLATION 9
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Page 401 and 402:
Page 403 and 404:
Page 405 and 406:
APPENDIX A ELECTROMAGNETIC ENERGY I
Page 407 and 408:
Page 409 and 410:
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Page 417 and 418:
Page 419 and 420:
Page 421 and 422:
Page 423 and 424:
Page 425 and 426:
Page 427 and 428:
Page 429 and 430:
Page 431 and 432:
Page 433 and 434:
APPENDIX B SOIL RESISTIVITY MEASURE
Page 435 and 436:
Page 437 and 438:
Page 439 and 440:
Page 441 and 442:
Page 443 and 444:
Page 445 and 446:
Page 447 and 448:
Page 449 and 450:
Page 451 and 452:
Page 453 and 454:
Page 455 and 456:
Page 457 and 458:
Page 459 and 460:
Page 461 and 462:
Page 463 and 464:
Page 465 and 466:
Page 467 and 468:
APPENDIX C PROTECTING AGAINST ELECT
Page 469 and 470:
Page 471 and 472:
APPENDIX D GROUNDING (EARTHING) ELE
Page 473 and 474:
Page 475 and 476:
Page 477 and 478:
Page 479 and 480:
Page 481 and 482:
Page 483 and 484:
Page 485 and 486:
Page 487 and 488:
Page 489 and 490:
Page 491 and 492:
Page 493 and 494:
Page 495 and 496:
Page 497 and 498:
APPENDIX E GENERAL CONVERSIONS AND
Page 499 and 500:
Page 501 and 502:
Page 503 and 504:
APPENDIX F R56 COMPLIANCE CHECKLIST
Page 505 and 506:
Page 507 and 508:
Page 509 and 510:
I NDEX Index Index AC power cabling
Page 511 and 512:
Page 513 and 514:
Page 515 and 516:
Page 517 and 518:
show all

standards and guidelines for communication sites - Radio And ...

Create successful ePaper yourself

Delete template?

Save as template?