[AMPS] Relays hanging up

[Tom Rauch]

I've never seen a DC relay hang up from residual magnetism.

The reason is the core material is intentionally a type that does not 
retain magnetism. If it is magnetized, it will simply magnetize again.

The reason most relays hang-up is because they weld into position 
from hot switching.

Lack of receive is more commonly caused by high resistance in 
the contacts, which is generally caused because the contacts are 
high current contacts designed to wipe when normal current 
passes through the contact. Running a 20 ampere relay at nearly 
zero amperes will almost certainly insure the relay will become 
unreliable over a period of time.

That is a constant fight when using conventional high current relays 
to switch receiving lines.

 
73, Tom W8JI
w8ji@contesting.com

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