Adjustment Of Operating Setpoint - Robertshaw VIBRASWITCH EURO366G Instruction Manual

The Vibraswitch, Model EURO 366G, may be used in conjunction with the Vibraswitch Monitor, Model 563A. The monitor
is a solid-state electronic system designed to "sort-out" false signals received by the Vibraswitch so that Alarm and/or
Shutdown of the operating machine will not result from false, transient disturbances, but any continuous vibration level
which exceeds the Setpoint of the Vibraswitch will cause Alarm or/and Shutdown. Examples of transient disturbances are
the closing of pipeline check valves on pumping applications, the start-up of additional pumps on a line, and the initial
start-up of various operating machines. These disturbances may cause the Vibraswitch to "trip-out" if the vibratory shock
level is in excess of its setpoint. Please note that the Model 563A does not have CE or ATEX certification at this time.
4.2

ADJUSTMENT OF OPERATING SETPOINT

The operating setpoint for the Vibraswitch varies with the type of machine and its location (measurement point) on the
machine. The setpoint adjustments suggested in this instruction manual are for machines which are functioning in a
"good" or "normal" condition. This method follows the concept of vibration tolerance for the machine and in this case is
dependent upon an individual who is experienced in the operation of the machine to define the vibration as "normal",
"fair", "slightly rough", etc. These various degrees of machine vibration are, therefore, based on individual's physical per-
ception between normal and abnormal roughness while the machine is operating.
It is agreed that this method can lead to differences in the classification of degree of vibration between individual ob-
servers. It is Robertshaw's contention, and experience bears out this conclusion, that if the machine is operating satisfac-
torily as previously defined and the acceleration as measured by the Vibraswitch is within certain limits, the settings as
outlined in the instructions will offer protection to the machine and prevent catastrophic failure.
For example, assume that a relatively new machine which, in the experience of the operator, is operating as "smooth" or
"good" regarding vibration and the Vibraswitch measures this acceleration level to be 0.25 g above its static condition
(zero). Experiences suggests that a reasonable level for alarm conditions would be a minimum of twice this value or 0.5 g.
It must be acknowledged that such a definition or upper vibration limits (alarm condition) on the machine may not have
adequately defined the upper tolerance limit of the machine before major repairs or excessive machine damages occurs.
It does, however, define a limit which, in our experience, has proven to be safe. As the user becomes more adept in using
the Vibraswitch as a monitoring device, his experience may dictate an higher setpoint more in keeping with the experi-
ence he has gained on the particular machine.
The Model EURO 366G Vibraswitch is adjusted by a simple three-step procedure. In making these measurements the
cover must be removed to gain access to the Setpoint adjusting screw. (Ref. Figure 4-2.)
Zero Vibration Level Measurement
a.
With the equipment on which the Vibraswitch is mounted not operating, back off the Setpoint adjusting screw
counterclockwise (CCW) two turns and press the reset button. Then turn the Setpoint adjusting screw slowly clock-
wise until actuation occurs (the armature assembly is against the latch magnet, Figure 4-1). This is the zero vibra-
tion point, or actuating point, with the machine not operating. A mark should be made with a lead pencil or other
convenient means to permanently record this "zero vibration point". Subsequent measurements are made relative
to this point.
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