Metrix 440 - Mechanical Installation

Doc# 90018-031 • REV L (April 2016) Page 4 of 16
4. MECHANICAL INSTALLATION
4.1 Where to Mount the Switch
It is desirable to mount the electronic switch (or transducers for switches with external
transducer opon) on a bearing housing, since the forces generated by the rotang parts
through unbalance, misalignment, bearing wear, etc., are transmied to the machine’s cas-
ing through the bearings.
Most bearing housings are curved so it is necessary to aach a bracket with a at surface for
mounng the switch. If the machine has bolted end plates on the bearings or horizontally
split bearing housings, these bolts can be used to aach the bracket.
When bolt holes are not available or are not suitable, an alternave way is to weld an angle
iron bracket similar to that in the sketch, but oriented so as to straddle the bearing housing.
The best approach will typically be to mount a gusseted bracket, as shown below.
The guiding principle is to ensure that the bracket is suitably s such that machinery
vibraon is completely transmied through the bracket to the vibraon switch or sensor.
Problems can occur when the bracket is too compliant, and may allow bracket resonance
to amplify the actual machinery vibraon, resulng in false shutdowns or alarms. For many
applicaons, 3/8 Inch material (preferably steel) will be suitable.
4.2 SwitchSensiveAxis
The sensive vibraon “measuring” axis is perpendicular to the mounng base of the unit
(vibraon switch or transducer). Always mount the unit such that the desired vibraon of
the equipment being monitored will occur along this axis.
NOTE: Models using an external sensor will be sen-
sive along the sensor’s axis, not the switch’s axis.