Instantel Minimate Pro Series, Operator'S Manual, Page: 109 / 124

Minimate Pro Operator Manual
10
–7
Refer to the illustration above and follow the installation instructions below:
1. Using the Geophone Wall Mount as a template, orient the block as shown, and mark
the location of the two holes to be drilled.
2. Remove the Geophone Wall Mount, and drill two 12mm (.47 inch) diameter holes;
drill the holes to a depth of 89mm (3.50 inches).
3. Place a nut on the end of each wedge anchor bolt to protect the threads, and using a
hammer, securely drive each bolt into place. Ensure that at least 32mm (1.25 inches)
of each of the wedge anchor bolt threads extend from the wall.
4. Remove the nuts from the wedge anchor bolts, and reposition the Geophone Wall
Mount. Secure it using two washers, the two nuts previously removed, and a deep-
throat socket with a ratchet.
5. Position the Geophone (not included in the kit) on top of the Geophone Wall Mount,
aligning the through-hole of the geophone with the mount; secure it using the bolt,
washer, and wing nut. Ensure that the arrow on the ISEE Geophone is pointing in
the direction of the Event. Hand-tighten the wing nut – DO NOT use a wrench or
pliers to tighten the wing nut, as this may damage the Geophone.
6. Ensure that the Geophone is securely attached to the Vibration port on the
Minimate Pro .
7. Press the Sensor Check key on the Minimate Pro to ensure that the sensor is
properly attached.
10.4.3. Geophone Theory of Operation
This section describes how
Instantel’s
Geophones operate. A Geophone measures ground
vibrations. The actual mechanism inside the Geophone is called a transducer. Geophones have
either one transducer, called Uniaxial Geophone, or three transducers, called Triaxial Geophones.
a. Geophone Operation
Functionally, a geophone sensor is a coil of wire suspended around a magnet. The magnet is free
to move in a field of magnetic flux lines. By Lenzs' Law, induced voltage is proportional to the
speed at which flux lines are traversed. Induced coil voltage is therefore proportional to the
relative velocity of the coil to the magnet. In practice, it does not matter whether the coil or the
magnet moves. Only the motion and speed relative to each other are important.