HARDWARE MANUAL Document reference MAMPS-HW/E
VM600 machinery protection system (MPS) Edition 18 - March 2022
7-18
Shaft relative expansion
PROCESSING MODES AND APPLICATIONS
7.9.2 Double shaft taper method
(1) Description
Two probes are used in this configuration, with each probe facing one side of a double shaft
taper (see Figure 7-13). This solution is simple and effective, allowing large measuring
ranges if the taper angle is small (for example, for a taper angle of 5°, the measuring range
is increased about nine-fold).
This method allows the measuring range to be extended by a factor of 1 / sinα:
ΔL = ΔG1 / sinα =
−ΔG2 / sinα
=> 2ΔL = (ΔG1
− ΔG2) / sinα
=> ΔL = (ΔG1
− ΔG2) / 2sinα
finally,
ΔL = [ (GAP1
− GAP1
i
) − (GAP2 − GAP2
i
) ] / 2sinα
where GAP
i
is the initial gap value.
Figure 7-13: Two proximity probes mounted near a shaft fitted with a double taper