ADASH Ltd.
Adash 4900 – Vibrio M
Further technical and contact information can be found at www.adash.com
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Standards for vibration measurements
Using a standards is occasional topic in vibration diagnostics. Because there are a lot of different
types of machines it is impossible to determine the critical limits of vibrations for wide range of
machines. Its reliability would be low then. It would happen, you will repair machine, which do not
require it. The standards should be rather determined for a narrow range of machines.
A4900 - Vibrio M contains Adash limit values and ISO 10816 limit values. Adash limits are not
rewritten from any existing standard. It’s a result of 20 years of Adash engineering team experiences.
It’s difficult to invent critical value definition which would be simple (that means not many parameters
such as speed, power, bearing type, machine type and so on) and reliable.
On the figures below is clear how we derived limit values. Three levels of machine condition are
defined: GOOD, ALERT (Machines lays in this range are not acceptable for a long period operation,
they could be operated till time when could be repaired) and DANGER (Vibration values in this range
are considered as very dangerous an they can cause a damage of the machine). The corresponding
colours are taken from traffic lights - green, yellow and red.
All limit values are related to the speed value. The low speed machine should generate lower vibration
then higher speed machine.
In the graphs area you found three particular areas. GOOD condition is the space up to the yellow line
that means operation without restriction. The space above yellow but under red line is an ALERT
condition. Possible to operate the machine but have to be more checked. It’s necessary to determine
the source of worse condition and plan repair (for instance change the bearing) or maintenance
(balancing, alignment). The space above red line is an DANGER condition and the machine should
not be operated. First figure contains the values for overall machine condition and you search
unbalance, misalignment, and mechanical looseness above all. They are called “overall” because we
can measure them on most of the measuring points. Second figure contains the limit values of a roller
bearing condition. This condition is local and can be measured only on appropriate bearing house.
Work with figures is simple. It’s necessary to know the speed. Instrument determines it automatically
or user can enter it manually. On the bottom horizontal axis you should find the point which
corresponds with speed. Above this point you will find an intersection with orange and red graph.
Projections to the vertical axis will determine limit values for yellow or red state. If the measured value
is lower than yellow the condition is GOOD – green. If the value is above yellow but under red then the
condition is ALERT – yellow. If the value is higher then red graph then the condition is DANGER – red.
