Setup, Torsion balance setup – PASCO ES-9070 COULOMB BALANCE User Manual

Page 9

012-03760E

Coulomb Balance

Setup

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.

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

support

tube

lateral support bar

Figure 4. Zeroing the Torsion Balance