I read in sci.electronics.design that Spehro Pefhany wrote (in ) about 'How to clean relay contacts?', on Fri, 4 Feb 2005:
The AN/APN1 included a moving-coil-driven differential variable capacitor, used to produce the FM signal. People used them to make primitive sweep generators. The acorn tubes were also handy for that project.
Contactors also have arc quenching features built in. And seriously large contact-contact spacing when open (the 2 pairs of contacts helps too) unlike most relays. It was always fun designing relays into circuits with a given creepage & clearance - open up the relay, and look at the tiny gap between contacts - often 0.5mm to 1mm.
Cheers Terry
No problem. We used to encounter this in the amateur radio service on a regular basis before the advent of solid state switching.
Run the armature to some low voltage, say 12 volts. Get a couple of 25 to
50 watt 12 volt bulbs (automotive lamps work well). Connect the bulbs, one to the NC terminals and one to the NO terminals. Toggle the relay a few times. If the resistance is now within specifications, you've cleaned the contacts. If not, you might want to consider the trick using the coil voltage for the bulbs and connecting the relay up as a buzzer and letting it go for five minutes or so.Jim
No problem. We used to encounter this in the amateur radio service on a regular basis before the advent of solid state switching.
Run the armature to some low voltage, say 12 volts. Get a couple of 25 to
50 watt 12 volt bulbs (automotive lamps work well). Connect the bulbs, one to the NC terminals and one to the NO terminals. Toggle the relay a few times. If the resistance is now within specifications, you've cleaned the contacts. If not, you might want to consider the trick using the coil voltage for the bulbs and connecting the relay up as a buzzer and letting it go for five minutes or so.Jim
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