The issue has dealt with specific makes and models with and without RFI, but as PWM is by its nature an RFI generator we need to stop and think about how companies (any company) acquires the motors a
It is critically important to realize that it is EASY to build a PWM system without RFI if you simply pay attention to the fundamental laws of physics -- keep track of where the current flows, ALL of
I'm still trying to wrap my mind around building switching power supplies<:-)) But when a company contracts out motor controllers they are interested in performance and cost. One thing companies are
You are very correct. Maybe 4yrs ago my co op which consists of about 15 buildings in a few block radius upgraded its original elevator systems. The originals were just relay racks and motors, most w
Jim and others, I have taken several EMC compliance classes over the years and they always stress that there are 3 main issues that contribute to RFI. They are in no particular order: 1.) Signal rise
You nailed it! Today the FCC is run by lawyers & politicians neither of whom like to deal with engineers & technicians. Even noticed this bias among hams who are lawyers although to a much lesser deg
Larry, The issue of rise time may also be inflexible for some systems. While I have often encountered design situations in which rise time was considerably faster than required (the digit guys wanted
Dale, I agree in some instances but the discussion here has been for motors of significant size in appliances. Rise times when driving something such as a motor with a large mass is not that importan
Agreed on both counts. 73, Jim K9YC _______________________________________________ RFI mailing list RFI@contesting.com http://lists.contesting.com/mailman/listinfo/rfi
Larry, I agree about motors, in and of themselves, not being particularly sensitive to fast risetime needs. Yes, the driving waveform could be slowed down by appropriate filters, but I do urge cautio