Metrix 440 - Page 5

Doc# 90018-031 • REV L (April 2016) Page 5 of 16
4.3 ChoosingMounngOrientaon
The vibraon switch can be mounted in the vercal or horizontal orientaon (or anything in
between) without a change in its sensivity. Ideally, the mounng orientaon will be chosen
by measuring the vibraon levels in both direcons with a vibraon meter and then select-
ing the direcon in which the highest vibraon occurs. This will typically be horizontal, since
most machine structures are less rigid horizontally than vercally.
4.4 NumberofPointsperMachine
Anywhere from one to four switches are used per machine (depending on how crical the
machine is to the process or how expensive it is), one on each end of the motor and one on
each end of the compressor, fan, pump or whatever is being driven. If there is a gear box in
between, one may be used here also.
It is quite common to use only one switch. In this case, it is best to mount on or near the
driven bearing. For example, if you have a motor and large fan with a bearing on each end
of the fan, the fan bearing on the motor side would be the driven bearing. It will usually see
the highest forces and have the highest vibraon level.
4.5 MounngatotherLocaons
When it is not possible to mount the switch directly on the bearing housing, the switch can
be located elsewhere, keeping in mind that it is usually machinery vibraon that is being
measured (not bracket, piping, or other vibraon). Do not mount the switch in locaons
where very lile machinery vibraon is transmied, as the switch will be less sensive to
damaging changes in machinery vibraon levels. Again, it is desirable to survey the machine
with a vibraon meter. If the level at the intended locaon is not aenuated by more than
about 50% relave to the levels directly on the bearing housing, it will probably be sasfac-
tory. However, alarm and shutdown sengs should then be reduced proporonately as well.
4.6 MounngSurface
Choose or fabricate a solid (rigid) surface (on the equipment being monitored) to mount
the vibraon switch or transducer. This will ensure transfer of the vibraon to the vibraon
transducer, while not introducing erroneous vibraons. In addion, the surface presented to
the base of the unit should be at. Fasten using sturdy hardware at all places provided.
4.7 TemperatureConsideraons
The switch is designed to dissipate internal heat by conducon through its base. Hence, it is
important to keep the mounng surface below the switch max temperature limit of 140°F. If
the equipment being monitored is going to exceed this limit, consideraon should be given
to either using one of the remote transducers, or thermally isolang the switch. To ensure
accurate switch performance, a warm up me of 5 minutes is recommended.
4.8 ElevaonConsideraons
The reduced atmospheric pressure at elevaons more than 2,000 meters (~6600 feet) above