Technical data are subject to change without notice.
© Copyright SPM 2002-04. 71650.B
SPM Instrument AB • Box 504 • S-645 25 Strängnäs • Sweden
Tel +46 152 225 00 • Fax +46 152 15075 • info@spminstrument.se • www.spminstrument.se
Measuring points, examples
The following two pages show measuring points and possible adapter or transducer installations.
How to install measuring equipment is described in the SPM installation manual.
Through hole for long adapter
Figure A shows how a measuring point beneath a fan cover can be reached with a long adapter,
through a hole in the cover.
Adapter with lock nut
In figure B, the fan cover is fastened directly to the motor shield, which is also the bearing housing.
One of the cover's holding screws can be replaced by an adapter with lock nut.
Bearing housings beneath brackets
Consult machine drawings and identify the bearing housing before selecting a measuring point.
In figure above, showing a pump, the bearings are placed in two separate housings inside the
bearing bracket. Measuring point 2, placed below and opposite to the pump outlet (load direc-
tion!) can be reached with a long adapter through an opening in the pump shield.
The bearing pair at measuring point 1 can be reached with a long adapter through a clearance hole
in the bracket. The hole must be large enough to allow bearing adjustment and still prevent
metallic contact between bracket and adapter.
Multiple bearings in one housing
If there are several bearings in the same housing, they are normally treated as a single bearing. In
The figure above shows the bearing arrangement for a vertical pump. It is not possible to
distinguish between the shock pulses from the paired bearings in point 1.
There is also a risk for cross talk between point 1 and point 2, which means that the shock pulses
from the bearing in worst condition are picked up in both points. Check signal strength with the
probe. Use one measuring point only if readings are identical in both points. This point (x) can be
placed halfway between points 1 and 2.
A
B
1
2
SPM measuring points and transducers 15
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