Boltek EFM-100, Installation And Operator'S Manual

Page: 19 / 46

C H A P T E R 2 - I N S T A L L A T I O N
13
Power Connector
Connect the black cable from the field mill’s power connector to the EPM-1 Power
Module’s field mill power connector. The cable supplies 12VDC to the field mill and
carries the analog output signals back to the EPM-1. See the Lightning Hazard caution in
the EPM-1 Analog Output section of this manual.
Fiber Optic Connector
Connect the orange fiber optic cable from the field mill’s fiber optic connector to the
EFA-10’s fiber optic connector. The fiber optic cable carries electric field data from the
field mill to the EFA-10 and ultimately to your computer. See the detailed drawings of the
fiber optic connector and note the keyway and locking tabs on the connectors. Orient the
key and locking slots properly on the male connector before attempting to insert the male
connector into the female connector.
Ground Connector
Connect the connector end of the green ground wire to the field mill ground connector.
The other end of the green ground wire connects to the field mill mount’s ground
connection. When mounting the field mill it is important to properly ground the field mill
and the field mill mount. The field mill is grounded through the green ground wire. The
field mill mounting hardware (mast and/or tripod) needs to be grounded though suitable
sized copper ground wire to your building central ground point. See Grounding Detail
for more information.
Sensitivity Connector
The sensitivity connector accepts a sensitivity plug to reduce the sensitivity of the field mill.
Several different values are provided so you can choose an appropriate value for your
installation. See
Chapter 1: Intensification of Electric Field for a description of why
this is necessary.
Figure 14: Sensitivity Plugs
With no plug installed the field mill has a relative sensitivity of 1.0
Sensitivity plugs reduce the sensitivity to compensate for the enhanced electric field of a
field mill mounted above the surface of the ground. Lower numbers represent lower
sensitivities. For example, the 0.25X plug will reduce the sensitivity to ¼ of the field mills
normal sensitivity.
Fortunately most installations won’t require a precisely calculated correction factor. On a
clear day simply choose the sensitivity jumper which produces field values closest to the
normal fair-weather electric field of 0.1 kV/m. If electric field readings during