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Old 9th Oct 2018, 10:07 pm   #6
Argus25
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Miniature relay Suppressor

Quote:
Originally Posted by cathoderay57 View Post
Thanks for the replies. I have some spare Class X2 0.1uF 275v AC caps. Is one of those across the contacts likely to do the job?

Cheers, Jerry
One experiment you could do, after you have used it for a year, depending on how often the motor goes on & off, is to check the uF value of the X2 capacitor. In this application (if it is a typical metalized paper type) you will probably find the uF capacity has dropped down, because with each snubbing event the film is often slowly destroyed. I have given up on these now and I would simply use a 0.1uF 1000V or 1500V DC rated poly or MKP cap as the snubber, or a 1200V 0.1uF capacitor rated for use in a colour TV's line output stage as a tuning capacitor , is a very good choice as they have a very low ESR. These caps will all be bigger and bulkier than the X2 cap but they won't degrade with time. A 1000V rated oil filled capacitor is also a good choice.
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