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Problem/Question (November 17, 1998):
I am looking for different methods of determining the projected life of incandescent lamps in a non-destructive manner. The test is to evaluate prototype and production lamps. Any information is grately appreciated.

Thanks in advance

Contact Name: Kevin Deighton
Phone: 310-326-4700
E-mail: kdeighton@pelican.com

Company Name and Address:
Pelican Products
Torrance, CA

Solution/Answer: Can you help?

The discussion thus far:

(January 31, 1999): Nondestrucive testing of incandescent lamps is an interesting problem. Let us first find out on what possible factors life depends. Inherent factors resident with the product due to design, manufacturing, QC etc. The external factors are voltage fluctuations and environmental factors. After study of these one can evolve a test method. Current drawn will be an indicator. Current will increase as end of life nears. This excludes failures due to vibration and shock.

Would like to have views of others.

Contact Name: Dattatraya Vishnu Petkar
India
Email: dvpetkar@bom4.vsnl.net.in

(October 13, 1999): The question regading condition monitoring of incandescent lamps posed on the " help " line of SRE came to my notice recently. Here is my contribution to the discussion.

The failure mechanism of incandescent lamps is as follows : There are local constrictions in cross section of the filament caused by manufacturing imperfections. Locations close to the filament terminations are more vulnerable. The operating temperature of the filament is higher at such constrictions. The differences are small but sufficient to cause higher rates of sublimation of tungsten from such spots. As this process continues, the constriction becomes worse and this establishes a vicious cycle of acclerating degradation which culminates in the burning out of the lamp sooner or later. Sooner if the lamp voltage is high , later if the voltage is low. The average life obtained at rated voltage depends on the precision and uniformity of the cross section of the tungsten filament.

The temperature differences at constrictions are very small under steady state conditions due to the conduction of heat along the length of the filament. However, in the starting phase ( lasting a few milliseconds) when a lamp is switched on, the temperature differences are higher. In fact this is the reason why all incandescent lamp burn-outs occur when they are switched on.... a fact noted by most house-holders. This suggests a possible non-destructive method for condition monitoring of incandescent lamps.

Pass a measured pulse of current through the lamp being tested. The pulse should be strong enough to bring the whole filament to red heat. Look at the filament through an infra-red camera with a storage-type display.The number and intensity of hot spots in the filament may give a reliable indication of the imminence of failure. Test parameters and display norms can be established after making tests on lamps of different ages in service and correlating the data with the actual life obtained in service after these tests.

I am not aware of any instrument manufacturer who has developed and marketed such a device. If there is someone out there who has already a device like this or who is prepared to develop it, or if there is any other device based on any other principle which can achieve the same result, he may get in touch with the correspondent who posed the original question and also with me because it interests me too.

Contact Name: A. A. Hattangadi
India
Email: nakul@one.net.au

Problem/Question (November 10, 1998):
I work in a research group and I am interested in applying a new model for probability estimation in the reliability area. I want to test it on systems (electronic, electrical or mechanical systems) and it would be very helpfully for my work if you can help me with two problems I am having. The first is that I don have failure statistics for systems and don't know where to get good samples of failures, and the second is to decide which validity criteria to use for the results I reach.

I have already tested my model using software failures and the validity criteria I used in that case was the total amount of failures predictive capability, but I think it wouldn't be a good criteria in systems reliability.

Thank you in advance, and have my apologize if I disturb you.

Contact Name: Ing. Jonas Pfefferman
Phone: None given
E-mail: jpfeffr@fi.uba.ar

Company Name and Address:
Universidad de Buenos Aires
Buenos Aires, Argentina

Solution/Answer: Can you help?

Problem/Question (October 22, 1998):
I have an interesting problem with reliability projection where one of the customers is asking for use of the AMSAA growth model where little or no detailed rel data is available (off-shore partner). Point Estimates have a significantly lower value than the required R, while 'fixes' have testing with little or no statisitical significance. Anyone have any experience, ideas or comments on how or if the AMSAA growth models would work under these conditions.

Contact: Russell W. Morris
Phone: 425-393-9373
E-mail: russell.w.morris@boeing.com

Company Name and Address:
The Boeing Company
Kent, WA

Solution/Answer: Can you help?

Problem/Question (October 20, 1998):
I work in the Air Force and am trying to determine if there is a conversion factor or formula for MTBF (Mean Time Between Failures expressed in hours for avionics equipment) and the Mean Time Between Maintenance (Inherrent).

If there is an expressed relationship or formula for this I would appreciate any comments or inputs.

Please call me at 937-255-7777, ext 3215 if you would need more details or information. My E-Mail address is rhunt@afit.af.mil.

Contact: Major Ron Hunt
Phone: 937-255-7777, ext 3215
E-mail: rhunt@afit.af.mil

Company Name and Address:
US Air Force Institute of Technology
Wright Patterson Air Force Base, OH

Solution/Answer: Can you help?

The discussion thus far:

(March 14, 1998): Dear Major Ron Hunt, I am not able to understand your question properly. However I am attempting to do so. System Availabilty depends on MTBF and MTBM by the relation:

Contact Name: Dattatraya Vishnu Petkar
India
Email: dvpetkar@bom4.vsnl.net.in

Problem/Question (September 29, 1998):
I would like to let you know that, I work at PT. Persero Pelabuhan Indonesia II as IT (Information Technology) Dept.

As IT Dept. I always need some books in English edition freely to support my job and study.

You know that my country have big economy problem. everything is very expensive.

In the next year (1999) I'll study at University of Indonesia to get Electrical Engineering. So in the next year I'll learn some subjects, as follows : Basic of Electrical, Basic of Electronic & Digital, and about Computer & Control.

To support my work and study, would you kindly send me some books or catalog and data sheet books about those subjects. For example:

- Electronic & Digital Standards
- Electrical Standards
- Telecommunications Standards
- Information about ASQ
- Working with the ISO 9000 Network, ISO 14000, etc

Besides, I would be very happy if you could send me also some IEEE Standards Catalog.
Thank you very much for your kindness and I am looking forward to receive the books.

Always remain with
Kind regards,

Contact Name: Arif Hendrawan
Phone: 62-21-4301447 ext. 622
Fax: 62-21-4350548
E-mail: senthot@hotmail.com

Company Name and Address:
Bagian Pemasaran dan Datin
Unit Terminal Petikemas PT. Persero Pelabuhan Indonesia II
Jl. Sulawesi Ujung No. 1 Tanjung Priok Jakarta 14310
Indonesia

Solution/Answer: Can you help?

Problem/Question (August 29, 1998):
Does anyone have any experience on accelerated life temperature testing of electronic components (both active and passive), printed circuit boards (PCBs) and solder joints on PCBs?

Contact: Izhar Ahmad
Phone: 713-972-6664
E-mail: izhar.ahmad@waii.com

Company Name and Address:
Baker Hughes
Houston, TX

Solution/Answer: Can you help?

The discussion thus far:

(August 31, 1998): Reference your query regarding solution /answer. I had established Reliability Evaluation Laboratory and managed the same for nearly two decades back in India. For some personal work I am here for some time. Hope will be able to help you.

Before conducting accelerated testing at higher temperatures one will have to see that failure mode does not change. It is essential to see that components, PCBs, soldered joints are qualified firstly by conducting environmental tests, bearing in mind the environment to which the parts are subjected during the life time. It will be interesting to have detailed discussions.

Do write back.

Contact Name: D. V. Petkar
Phone: 203-372-9781
c/o MayankM@worldnet.att.net
3165 Main Street
Bridgeport, CT 06606-4225

(September 3, 1998): These components and PCBs are intended for sub-surface (Oil Well) operation. These circuit boards will be housed in pressure housing and will be installed at a depth greater than 20K feet. Minimum target for operational duration is 5 years at 150 deg C continuous.

I can be reached at 713-972-6664. Thanks for our interest and help.

Izhar

(September 11, 1998): Sorry I could not contact you as I was out of station. Your requirement for reliability is nearly similar to that of submarine repeater system. Submarine repeater life expectancy is 30 years as maintenance is externally costly. I have some more questions as follows:

1. Have you designed the system for life of 500 yr. to have practically no chance of failure in 5 years?
2. Have you taken into account stress factors and high temperature environment stress factor in predicting the reliability?
3. Have you used screened hi-rel qualified components?
4. Have you carried out Failure Mode, Effect and Criticality Analysis (FMECA)?
5. Are failure modes of components and parts under simulated laboratory conditions and field conditions analysed?
6. Is redundancy used? Is the redundancy parallel or voting? Systematic design and analysis will only guarantee reliability.

I am available on phone 203-372-9781.

D. V. Petkar

Problem/Question (August 27, 1998):
Does anyone have any experience on life testing of AC Motor used in Desk/Stand Fan? For example, I would like to guarantee my customers for one year and how I can prove to my customers regarding to the above?

Contact: SH Kong
Phone: 609-5483958
E-mail: kong.sh@softhome.net

Company Name and Address:
MEC Electrical Components Sdn. Bhd.
MEC City, 26300
Kuantan, Pahang, Malaysia

Solution/Answer: Can you help?

Problem/Question (August 14, 1998):
Does anyone know where I can get a copy of:

Title: "Mathematical aspects of Reliability centered Maintenance"
By: Resnikoff, H.L
Publisher: Dolby Press, Los Altos Califonia (1978)

Contact: Gerard Borg
Phone: 61-2-9767-7352
E-mail: gborg@agl.com.au

Company Name and Address:
Australian Gas Light Company
NSW 2194
Australia

Solution/Answer: Can you help?

Problem/Question (July 28, 1998):
Does anyone have any experience on accelerated life testing of MWIR and LWIR HgCdTe or InSb detectors? In particular, I am looking at the long-term stability of both contacts and passivation layers, and their impact on detector responsivity and noise.

The main focus has been (i) to develop fabrication technologies for improving long-term stability, (ii) to develop appropriate accelerated test procedures for identifying the degradation mechanisms, and (iii) to develop device models capable of predicting long-term reliability from accelerated life tests. Unfortunately, the way we perform these accelerated life tests have come under some scrutiny and I would like to get other peoples inputs and experiences on the subject.

Contact: Sean Keefe
Phone: 805-562-2102
E-mail: smkeefe@mail.hac.com

Company Name and Address:
Raytheon Systems Company
Santa Barbara, CA

Solution/Answer: Can you help?

The discussion thus far:

(August 17, 1998): It will be interesting to evolve a reliable accelerated testing plan for the products. I am presently here for a few months for some personal work. Hope will be able to help in the development of reliable accelerated testing methods.

Environmental Testing as per IEC standards is proof testing of the product. In fact these tests are accelerated tests done at maximum environmental stresses likely to be encountered by the product during its life. The product in question has connection reliability problem. Vibration accompanied by Low temperature will be a good screen test. However, without knowing the present test plans it will be difficult to suggest any improved program.

Contact Name: D. V. Petkar
Phone: 203-372-9781
c/o MayankM@worldnet.att.net
3165 Main Street
Bridgeport, CT 06606-4225

(August 17, 1998): Thanks for the input, to which product line were you referring to, regarding the accelerated life test?

(August 19, 1998): My mail was in response to your query dated 28 July as appeared in Can You Help of SRE bulletin regarding MWIR and LWIR HgCdTe or InSb detectors. You seem to have accelerated testing procedure with which you are not happy. Your focus on development of (i) fabrication technologies (ii) test procedures for identification of degradation mechanisms and (iii) models for reliability prediction are challenges.

Contact stability seems to be your critical problem. You must have identified the environmental factors which degrade the contact. If not one needs to identify these and their stress/strain relationship. If the degradation factors are known what is the stress level and contact life & noise characteristics relation to stress level. One need to go in detailed planning and experimentation with single and/or combined environment testing under step stress conditions before one goes for reliability testing.

I have given my views based on my experience in managing an independent Reliability Evaluation Laboratory for testing electronic items from devices, components to products and systems for nearly two decades.

Hope to hear from you more.

Contact Name: D. V. Petkar
Phone: 203-372-9781
c/o MayankM@worldnet.att.net
3165 Main Street
Bridgeport, CT 06606-4225

Problem/Question (July 22, 1998):
I need to know what the status is of the IEEE P1413 Manual is that will replace the MIL-HDBK-217 Spec. I would also like to know how I can get a draft copy as soon as they become available so that I can get started writeing software for it.

Contact: Bailey L. Hall
Phone: 541-471-0195
E-mail: baileyh@a1pro.net

Company Name and Address:
Ktech Engineering
1599 SE "N" Street, G106
Grants Pass, OR 97526

Solution/Answer: Can you help?

Problem/Question (June 25, 1998):
Eastman Chemical's Longview site employs 300+ maintenance personnel. We are looking for a process to analyze each maintenance function by critical equipment. The result of the analysis will be to redeploy our resources (people, equipment, etc...) by function rather than by Operating area.

Do you have such a process or interest in helping to develop such a process?

Contact: Bernie Beethe
Phone: 903-237-6214
E-mail: bernie@eastman.com

Company Name and Address:
Eastman Chemical Company
Longview, TX 75607

Solution/Answer: Can you help?

The discussion thus far:

(August 17, 1998): It was interesting to see the Question. I am here for some personal work and will be here for a few months. Think I will be able to help in the development of appropriate and optimal Maintenance Program. My views are as follows:

Maintenance-Corrective or Preventive-is required to maximise the system Availability. The system Availabilty depends on:

1. Failure rates of components
2. Failure mode
3. Effect of failure on system and its Criticality

What need be done is detailed FMECA-Failure Mode, Effect and Criticality Analysis of the systems and subsystems. In addition following information:

1. Type of System-Hazardous or otherwise;
2. Requirements of Availability in terms of MTBF;
3. Requirements of Maintainability-MTTR;
4. Requirements of Safety in terms of safe and unsafe failure rates;
5. Availabilty of information on Failure Rates;
6. Familiarity of the staff with Reliability Technology at a minimum is required to evolve a optimal Maintainability Program.

Contact Name: D. V. Petkar
Phone: 203-372-9781
c/o MayankM@worldnet.att.net
3165 Main Street
Bridgeport, CT 06606-4225