[AMPS] Relays hanging up
Sat, 12 Aug 2000 06:48:17 -0700
>> >> When we did that we could hear virtuallu hundreds
>> >> of relays clickking off held by residual magnetism.
>Well he "says" it was residual magnetism. I guess we have to
>believe somehow he knows that's what it was, and not weak
>springs or other mechanical problems.
Because the relay stopped hanging up when I reversed polarity.
>> >Mechanical non-mercury wetted relays in a telephone switching
>> >What a system. No wonder the materials in the relay magnetic
>> >parts were poor!
>> Ä ''poor''? All relay armatures contain iron. Hello. If the spring
>> isn't strong enough, it can hang up. >........
>That's right. With a weak enough spring, the relay won't have any
The relay did not hang up after I reversed the magnetic field.
>But if the iron is soft it should also have no flux storage.
All types of iron can be magnetized.
> If it does
>have flux storage, it would take a damn big hammer to
>"demagnetize" the metals in the relay.
>I haven't seen ANY amplifier relays stick from "residual
>magnetism". I suspect the most common flaws...dirt or other
>contaminants....contact welding from hot switching...are written off
>to "sticking relays from residual magnetism".
The contacts were not welded, Tom. Reversing the polarity fixed the
>I'm not saying it can't happen, just if the iron is too hard the relay is
>toast. It will immediately fail over and over again.
- Rich..., 805.386.3734, www.vcnet.com/measures.
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