Mean Time Between Failures

Table 1. 5520 MTBF (front-to-back airflow)
Ambient Temp = 25°C 5520-24T 5520-24W 5520-24X 5520-12MW-36W 5520-48T 5520-48W 5520-48SE
System base

(all boards, modules excluded)

 545,928 480,404 633,004 392,662 506,767 417,304 531,218
Complete system - A

(system base+full fans+1 PSU)
One 2000W PSU 185,080 174,532 179,138
One 1100W PSU 212,906 199,067 205,081
One 715W PSU 218,879 204,272 210,617
One 350W PSU 270,711 193,198 236,070 169,687
Complete system - B

(system base+ full fans+2 PSUs)
Two 2000W PSU 123,936 119,115 121,243
Two 1100W PSU 150,232 143,607 146,293
Two 715W PSU 156,248 148,663 151,992
Two 350W PSU 184,380 193,198 167,627 169,687
Note

Note

5520-24X and 5520-24T models have 2 fan slots; All other models have 3.
Table 2. 5520 MTBF (back-to-front airflow)
Ambient Temp = 25°C 5520-48T-BASE 5520-24T-BASE 5520-24X-BASE 5520-48SE-BASE
System base

(without PSU and fans)

 506,767 545,928 633,004 531,218

(system base+3 fans+1 PSU)
One 350W PSU 334,974 343,304

(system base+3 fans+2 PSUs)
Two 350W PSU 353,898 363,209

(system base+2 fans+1 PSU)
One 350W PSU 409,290 455,433

(system base+2 fans+2 PSUs)
Two 350W PSU 437,901 491,140
Table 3. 5520 MTBF (AC and DC power supplies)
Ambient Temp = 25°C 5520-48T-ACDC 5520-24T-ACDC 5520-24X-ACDC 5520-48SE-ACDC
System base

(without PSU and fans)

 634,091 697,627 717,424 618,066

(system base+3 f-b fans+1 PSU)
One 550W AC PSU 317,110 331,806 335,188 313,314
One 550W DC PSU 303,810 317,273 320,363 300,323

(system base+3 b-f fans+1 PSU)
One 550W AC PSU 297,612 310,520 313,480 294,266
One 550W DC PSU 317,057 331,749 335,128 313,262

(system base+3 f-b fans+2 PSUs)
Two 550W AC PSUs 355,926 374,545 378,860 351,150
Two 550W DC PSUs 344,636 362,064 366,094 340,156

(system base+3 b-f fans+2 PSUs)
Two 550W AC PSUs 339,289 356,168 360,067 334,947
Two 550W DC PSUs 355,877 374,492 378,805 351,103
Table 4. 5520 MTBF (AC and DC power supplies cont.)
Ambient Temp = 50°C 5520-48T-ACDC 5520-24T-ACDC 5520-24X-ACDC 5520-48SE-ACDC
System base

(without PSU and fans)

 251,134 286,740
9036817-00 Rev. AU