[Prev][Next][Index][Thread]
coupling question
Like many others my coil is constantly
changing as my knowledge and ability grows.
My knowledge of Tesla coils has grown by leaps
and bounds since finding this list and other
Internet sources.
One of the major changes I made was the addition
of a decent RF ground.I didn't have one at first because
none of the outdated plans that I had seen ever showed one.
I had the bottom of the secondary tied to the bottom turn
of the primary. As I moved up in power overcoupling became
a problem. I had lots of corona and arcing between the primary
and secondary. Raising up the secondary cured the problem. I
experimented with various heights until I found the best spot.
Then I added the RF ground. I disconnected the secondary from the
primary and attached the secondary base lead to RF ground. I left the
primary floating. All works well this way. Maybe a little more
spark and tuning is definitly sharper. After moving up to about
1KVA I was playing with the coupling trying for (what else?) more
spark. I found that even dropping the secondary down all the way
into the primary I got no arcing or corona. No indication at
all of overcoupling. Nothing changed except for adding the ground
connection to the secondary and removing the common connection from
primary to secondary. Has the coupling changed or is this floating tank coil
more forgiving. It does seem that the "sweet" spot is the same as
before. Anybody got any insight on this? I'm not looking for a
complete course on coupling. Just enough info so I can sleep nights.
Mike Hammer
mhammer-at-midwest-dot-net