Latest Project
I'm currently building a device that puts a smooth bend in sapphire optical
fiber using oxygen - hydrogen torches (tiny) as the heat source.
The basic idea is to heat and soften the 30mm long fiber as it is held against a
fixed stop. As the fiber softens, the carrier rotates, bringing a fresh section
of fiber into the torch flames. The bending must be slow and steady in order to
keep the crystal fiber from breaking or bending suddenly. Its not a trivial
task. The fiber is used to deliver laser energy for dental and orthoscopic
surgery.
The first version built a few years ago used a precision weight to provide the
turning force for the carrier turntable. ( A 35mm film can with a calibrated
number of BBs ).
My present version is a little higher tech, using a shaded pole motor driven by
a variable transformer as a torque motor. The motor is stalled and provides a
very smooth and steady drive to the gear that drives the turntable. This may be
an unconventional use for a shaded pole motor. I've also used them as a smooth
drag device by applying DC to the windings. The feeling is similar to moving a
magnet down an aluminum or copper sheet. This viscous drag is always surprising
to ordinary people. Fun listening to them trying to explain what is happening.
Earle Rich
Mont Vernon, NH
fiber using oxygen - hydrogen torches (tiny) as the heat source.
The basic idea is to heat and soften the 30mm long fiber as it is held against a
fixed stop. As the fiber softens, the carrier rotates, bringing a fresh section
of fiber into the torch flames. The bending must be slow and steady in order to
keep the crystal fiber from breaking or bending suddenly. Its not a trivial
task. The fiber is used to deliver laser energy for dental and orthoscopic
surgery.
The first version built a few years ago used a precision weight to provide the
turning force for the carrier turntable. ( A 35mm film can with a calibrated
number of BBs ).
My present version is a little higher tech, using a shaded pole motor driven by
a variable transformer as a torque motor. The motor is stalled and provides a
very smooth and steady drive to the gear that drives the turntable. This may be
an unconventional use for a shaded pole motor. I've also used them as a smooth
drag device by applying DC to the windings. The feeling is similar to moving a
magnet down an aluminum or copper sheet. This viscous drag is always surprising
to ordinary people. Fun listening to them trying to explain what is happening.
Earle Rich
Mont Vernon, NH