---------- From: Paul Paroff To: Darrell Locke Subject: RE: Correlating sine sweep with random vibration List-Post: emc-pstc@listserv.ieee.org Date: Friday, January 21, 2000 9:22AM
To add my voice to the many, there is no agreed upon correlation between sine sweep and random vibration. A paper written by Phil Rogers of Unholtz-Dickie Corp. and Shams Jawaid of Quantum Corp. to be presented at next week's RAMS conference may shed some light on the difference. The authors measured Grms vs time in miliseconds while the pneumatic table (as found in HALT chambers) was set to 1 G. The graph shows that to achieve a time averaged value of 1 G the table is exposed to up to 50 G spikes at approximately 30 ms intervals. So there doesn't seem to be the true equivalent of a sine sweep. I do agree with your opinion that if something can survive at 60 G on a random vibe table it should pass a 1 G sine sweep. However, you may have to go to an outside lab to satisfy your customer's requirement. Or, if budget is an issue, I bet you could swap some HALT chamber time for some ED shaker time with a neighboring company. Paul Paroff Reliability Engineer Advanced Input Devices ---------- From: Darrell Locke To: Paul Paroff Subject: FW: Correlating sine sweep with random vibration List-Post: emc-pstc@listserv.ieee.org Date: Thursday, January 20, 2000 2:59PM Any thoughts for Doug? DL ---------- From: POWELL, DOUG To: EMC-PSTC (E-mail) Subject: Correlating sine sweep with random vibration List-Post: emc-pstc@listserv.ieee.org Date: Thursday, January 20, 2000 2:11PM Hello all, As a part of the safety testing of our products we have a requirements for a vibration test. EN50178 (originally DIN VDE 0160) has a 1G sine sweep test that forces us to go to a nearby environmental test lab. Where we can find a voice-coil vibration table. The cost for one large one of these is prohibitive for my company. My question: Is it possible to correlate the sine sweep with random vibration and show compliance to the standard? A more economical solution for us would be to use one of several HALT/HASS chambers we have in-house. Intuitively, it seems that testing products at 60 G's or more, over a wide spectrum, should exceed the 1G sinusoid. But so far, everyone I know indicates there is no way to do this. By the way, I do understand some things about the dwell time and resonance's. Still I would like to hear your inputs on this... -doug ================================== Douglas E. Powell Regulatory Compliance Engineer Advanced Energy Industries, Inc. mailto:doug.pow...@aei.com http://www.advanced-energy.com ================================== --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
