Forum: Reliability & Maintainability Questions and Answers
Posted by: Lanna Parkinson
Date posted: Mon May 13 18:59:00 US/Eastern 2002
Subject: How to define the mission time for a Ticket Vending Machine
A Ticket Vending Machine (TVM) is always in a hot standby state. It is operating when there is a transaction request. Does its mission time only include the ticket transaction time, or will the dormant time be included? Could someone recommend some reference information on reliability concepts about hot-standby component?
Thanks in advance. Lanna
Posted by: Robert Webb (firstname.lastname@example.org )
Organization:Ultra Electronics, Controls Division, UK
Date posted: Thu May 9 13:01:50 US/Eastern 2002
Subject: Dormancy factors
I am seeking advice on reliability of electronics taking into account dormant periods. Can credit be taken for periods of non-operation to improve the reliabilty prediction of equipment that is only operational for a certain percentage of an overall mission? In my particular example, the equipment would be powered in a 'sleeping' state and not driving any loads for the majority of the mission. I have a copy of your 'Reliability Toolkit' which contains factors obtained from RADC-TR-85-91, but is this still applicable in current thinking? Your advice would be much appreciated.
Regards Robert Webb
Posted by: Terry Davey (Terry.Davey@motorola.com )
Date posted: Thu May 9 6:24:29 US/Eastern 2002
Subject: Clifon Seusy Article on Phenominal Rel Growth
I'm trying to locate an article by Clifton Seusy of H-P called "Achieving Phenomenal Reliability Growth" on ALT using a FRACAS type approach which I believe was in a onference proceedings from the 1980's. I've tried searching the RAC Library (where I believe I originally located it), but in the absence of an author search I find myself swamped by irrelevant hits.
Does anyone have the full reference, please? TIA.
Posted by: Lanny Gerber (email@example.com )
Date posted: Tue May 7 18:11:44 US/Eastern 2002
Subject: Telecordia SR-332
Is the new telecordia SR-332 dramatically changed or have they just updated their tables to reflect current design trends. Can you tell me what are the current changes ? Is it worth adding to a prediction toolkit?
Posted by: Paul (firstname.lastname@example.org )
Organization:TOSL Engineering Limited
Date posted: Thu May 2 14:42:57 US/Eastern 2002
Subject: vibration analysis
In my vibration spectra for a class one motor, the 120Hz peak is located at 4.13X in the low frequency range. I'm getting a peak of 0.21mm/s at this 120 Hz peak on the non drive end of the motor... when I look at the high range frequency readings I'm seeing two peaks spaced at a distance of 4.13 apart....in the radial, tangential and axial directions of the motor..one of these peaks has a value of 3.75mm/s in the radial direction ...I think that the motor has an electrical problem...but I can't specifically identify the electrical fault...can you help me on this, mentioning anything you can on the level of 3.75mm/s if you can . Thank you