Noisey MEM switch

Definitely not to be recommended but 55 years ago when I was an apprentice this was a common fault in the factory where I worked, cured albeit short term by sticking a layer of insulating tape to one side of the laminations. Instant result and happy workers who had been plagued by the noise. I never did find out how long this bodge would last and the factory is now a supermarket so never will know.

Phil

Edited By Philip Rowe on 11/11/2018 16:58:32

I know this is an old thread but readers might find this interesting.

In a former career we had technical vehicles with electronic transmission equipment running on standard single phase 240VAC mains, (from a trailer generator). There was a 36V DC battery back-up system to maintain the equipment in the event of a mains failure.

The 36V back-up supply had a relay so that if the mains disappeared, the relay would switch on the 36V and keep the electronics alive. On one particular van this relay always buzzed and frankly was a pain. By tapping the relay, you could sometimes quieten it.

About 5 years later myself and a colleague were stripping out and refitting the electronics in this particular van. When we came to the 240VAC power board, we discovered that the line conductor feeding the 240VAC from the tailboard connector into the van electrics had cracked completely through just above the soldered joint, but the wire was just touching together.

So, all those hours putting up with a buzzing relay ! The cracked line conductor obviously sometimes made a good contact, other times a poor contact, or a diode effect, causing the relay to try to switch on every cycle of the mains, and this caused the 50Hz buzz !! Oddly, the cracked wire passed line voltage and current very well - we would have noticed a drop in mains voltage or current limiting.

So, as someone in the thread did suggest, faults like these might point to a problem in the mains supply rather than the buzzing item itself.

Worth checking all connectors and switches in the mains path. Both the internal wire joints and the external plug and socket pins

Edited By John Doe 2 on 13/01/2022 10:20:32

Edited By John Doe 2 on 13/01/2022 10:23:23

As ever, coming in late, My NVR switch started to buzz.

Removal /strepping disclosed no problem. Refitting with the screws TIGHT cured the problem!

Possibly, if the problem is loose laminations, MAYBE painting the laminations with varnish (But not over the pole faces ) will help matters.

Howard.