Hello to All;
Many years ago Alpha used a very nice QSK sequencing circuit for the Alpha 77,
NOT 77DX,D,SX, just the plain 77 ( 1971). It used a RJ1a and a reed-relay,
a couple of diodes and a resistor. It was powered with 55 volts. Worked very
good and I have the diagram. I have used it for years at 1.5 kW and no problems.
73 de Price W0RI
On Sunday, August 30, 2015 7:01 PM, Tom W8JI <w8ji@w8ji.com> wrote:
> I'm not sure goosing the pull-in voltage is always a good idea. It may
> shorten the initial closing time a bit, but (depending on the relay)
> it can aggravate contact bounce, doing more harm than good. It also
> stresses the relay.
Done properly, it doesn't hurt a thing. The proper way is to use current
limiting.
It is safe to run 50 volt supplies on most 12 volt relays, but there is a
point of diminishing returns on speed. The high initial voltage ramps up the
magnetic field faster, but it does not cause excessive heat or current. This
is because the relay starts at near zero mA from inductance.
None of this matters, though. Using a relay on make for protection is a bad
idea. The de-active state should be used for protection, and the active
energized state used to allow RX.
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