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012-03760E
Coulomb Balance
5
Setup
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Note Threading the Torsion Wire:
The
Torsion Balance is shipped to you with the wire
already threaded. However, if it ever breaks,
you can thread it using the spare wire that is sup-
plied. See the procedure at the end of this manual.
Torsion Balance Setup
➀
One of the conductive spheres is not attached when the
Coulomb Balance is shipped. To attach it, just slip the
stem of the sphere
over
the fiber glass rod of the
pendulum assembly.
➁
Slide the copper rings onto the counterweight vane, as
shown in the bottom of Figure 3. Then release the
packing clamp that holds the counterweight vane, as
shown in the top of Figure 3. Adjust the position of the
copper rings so the pendulum assembly is level.
➂
Reposition the index arm so it is parallel with the base
of the torsion balance and at the same height as the
vane.
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Important:
When storing the torsion balance,
always clamp the counterweight vane to protect the
torsion wire. When you do this, be sure to adjust the
height and angle of the index arm so that you can
clamp the vane without pulling on the torsion wire.
➃
Adjust the height of the magnetic damping arm so the
counterweight vane is midway between the magnets.
➄
Turn the torsion knob until the index line for the degree
scale is aligned with the zero degree mark.
counterweight
vane
1. Loosen the top
thumbscrew
2. Loosen the side
thumbscrew and
rotate the index
arm so it is parallel
with the base of the
Coulomb Balance.
Then tighten the
thumbscrew.
packing
clamp
Releasing the packing clamp
degree scale
torsion knob
lateral support
bar
Figure 3. Setting Up the Coulomb Balance
magnetic
damping arm
Index arm
support tube
torsion wire retainer
pendulum
assembly
counterweight
vane
copper rings
copper rings
support
tube
lateral support bar
Figure 4. Zeroing the Torsion Balance