The performance criterion for surge in light industrial immunity is B. This 'allows' some degradation of performance within specified tolerance. For a power supply, this may imply that you can monitor the output using a meter. However, because a power supply is used for some other device, it may be advisable to monitor the output with a 'recording' device such as an oscilloscope or a datalogger. In this way, you can determine the duration and amplitude of any excursions of the output. This will allow you to specify, for a potential customer, exactly what he can expect during this environment.
The use of a "type of LED" may be a latching device, that will turn on the LED, only if the variation exceeds a certain amount of time. This may be acceptable, but you don't know the voltage characteristics of the excursion. So, you can provide results in the following ways: - multimeter - the output doesn't have a permanent change, or one that is detectable by the test engineer - no details - LED with time comparator - the output exceeded a threshold (dropout) for longer than a programmed time - no detail - recorder - details (depending on bandwidth of measuring device) of the amplitude and time duration of the anomaly The bottom line (as usual!) is how much money you want to spend vs. the quality of the data you want to present. Because the standards allow the user to define performance, a power supply manufacturer can simply say that it passes as long as the output voltage change is not perceptible on an analog meter. Customers seeking to buy a power supply may not agree, but this is a competitive issue, not a regulatory one. Bob Martin, PE, NCE Sr. Technical Manager Intertek Testing Services (978)263-2662 fax(978)263-7086 r...@itsqs.com The opinions expressed are my own and not necessarily those of my employer. -----Original Message----- From: peterh...@aol.com [mailto:peterh...@aol.com] Sent: Monday, March 08, 1999 1:08 AM To: emc-p...@majordomo.ieee.org Subject: Surge immunity Hello all, Please could someone advise me how to monitor the performance of a component level power supply such as open frame type during a surge immunity test? I.e what instrument is used to observe the output of the power supply during the test? I have been told by an EMI lab that they use normal multimeter whereas another lab uses a type of LED. Are these really the correct way of monitoring the performance A, B and C as described in the standard? Thanks Peter --------- 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, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
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