I have never used a "ground ring" except in the context of a ground grid on double-sided PCB's. A "ground ring" alone, as suspected by buzzp, is a jim-dandy loop antenna that both emits and receives external RFI noise. If buzzp keeps it for other reasons mentioned by the group, it should be...
I have used parts count MTBF's with considerable success in predicting warranty return rates. The MTBF predictions have fallen within the 90% chi-square confidence band of the actual return rate. If appropriate derating is used (90% of junction temperature, voltage and current ratings and 50%...
BS EN standards are almost inevitably verbatum restatements of the IEC standard. The only standard I have ever encountered that takes exception to the IEC standard is UL 60601-1.
Thanks again!
Because of the nebulous border between EN61010 and EN60204, I have been addressing the requirements of EN60204 in my EN61010 analyses. Obviously I do not want to risk killing our products by needlessly overspecifying the requirements.
From what I can tell, EN50178 does not...
My employer, a manufacturer of pumps and pump drives for laboratory and industrial process use, has been self-certifying to the Low Voltage Directive using EN61010, as have our competitors. Since our products "control one or more output quantities" (Article 1.1.1.b) and are "used...
See IEC 60812, available from:
http://www.iec.ch/
Also helpful:
MIL-STD-1629 (FMEA - Obsolete)
MIL-HDBK-338 (Component Failure Mode Frequencies)
MIL-HDBK-217 (Component Failure Rates)
Copies can be downloaded for free from:
http://assist2.daps.dla.mil/quicksearch/
Standards used to assess compliance with the EU EMC Directive (EN 50081-1 & -2, EN 61326-1, and EN60601-1-2) distinguish between Heavy Industrial Locations, which must meet CISPR 11/16/22 Class A emission levels, and Light Industrial Locations, which must meet more stringent Class B emission...
Check the turn-off characteristics of the opto-triac. These are quite slow and may conduct through line cross, causing the SCR or Triac to prematurely turn on during the next cycle.
Corcom is good and is readily available through distribution. Delta and Schaffner have lower priced units, but you get what you pay for. TRI-MAG in Visalia, CA, has a good line, but you have to deal with them direct, they may not have it in stock, and you will need a charge card.
In sizing...
Argh! That should be "inertia", not "motor back-EMF". The armature inductance together with the armature inertia acts like an LC filter. Sorry.
In a DC motor, the armature, in conjunction with the motor back-EMF, acts like an LC filter, with the motor speed proportional to the average of the rectified applied voltage. Consequently, a common means of controlling the speed of a DC motor is to replace the bridge rectifiers with SCR's...
Unfortunately, trial and error is the only reliable way. Everytime I think I have a handle on the problem, the very next project throws everything I've ever learned about EMC out the window. The EMC test house should have a large variety of EMC line filters on hand to help the selection. Do a...
