IEEE 1478-2001 pdf download IEEE Standard for Environmental Conditions for Transit Rail Car Electronic Equipment
4.1.4 Vibration Equipment shall withstand the Table 1 vibration environments in all shipping, storage and operating modes without damage, degradation, or abnormal operation. To verify that the equipment can withstand the operating environment vibration tests shall be performed according to the following procedures:
a) The equipment shall be subjected to sinusoidal cycling along each of the three mutually perpendicu- lar axes. Each cycle shall consist of a sine sweep from 5 Hz to 1000 Hz and back to 5 Hz for condi- tions E1, E2 and E3 of Table 1 and from 5 Hz to 200 Hz and back to 5 Hz for conditions E4 and E5 of Table 1. During each sine sweep, the frequency of applied vibration shall be swept over the spec- ified range logarithmically. Sweep times shall be 12 minutes for the 5 Hz–200 Hz–5 Hz range and 17 minutes for the 5 Hz–1000 Hz–5 Hz range. These sweep times are equivalent to a logarithmic sweep rate of approximately 0.9 octave per minute. Twenty (20) complete sine sweep cycles shall be applied along each of the three mutually perpendicular axes. Test durations for each axis shall be 4 hours for the 5 Hz–200 Hz–5 Hz sweep case and 5 hours 40 minutes for the 5 Hz–1000 Hz–5 Hz sweep case. Input vibration levels shall be as specified in Table 1. Each sine sweep consists of a con- stant displacement input over the initial low frequency range, followed by a constant acceleration input over the remainder of the frequency range up to the peak frequency.
b) Exploratory Sine Sweep: It is recommended that an exploratory sine sweep test be conducted during the design phase to identify equipment resonances and potential problem areas. This test should be conducted at a vibration level of 1.3 mm peak-to-peak displacement (5–14 Hz) and an acceleration input of 5m/s 2 peak over the remaining frequency range for the appropriate conditions where the equipment is applied as specified in Table 1.
c) Equipment Mounting Technique: The equipment shall be attached directly to the vibration exciter or transition table. For large equipment items that do not conveniently fit the vibration exciter or transi- tion table, a rigid fixture shall be used to connect the equipment item to the exciter or transition table. The rigid fixture shall be capable of transmitting the vibration conditions specified herein. The input control sensing device(s) shall be rigidly attached to the vibration table, or fixture if used, as near as possible to the attachment point(s) of the test item. Equipment that is normally vibration-isolated in service shall use the service isolators when mounted for the vibration tests.
d) Test tolerances: The tolerances for the test conditions shall be as follows: Vibration Frequency: ± 2 percent or ± 0.5 Hz for frequencies below 25 Hz Vibration Amplitude: ± 10 percent
e) In the sweep test, sufficient number of accelerometers shall be used to identify vibration characteris- tics of those units or subassemblies, which are susceptible to the vibration, representative of other units, and/or critical to performance of the equipment.
IEEE 1478-2001 pdf download
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