RM-3WE (THREE WAY) ACCELEROMETER

GENERAL

The RM-3WE accelerometer measures and permanently records, for period of 30, 60, and 90 days,

the magnitude, time of shock (impact) and vibration on three axis: vertical, lateral, longitudinal.

The RM-3WE may be used interchangeably to monitor all modes of transportation and record handling

errors. It is an excellent accelerometer for laboratory testing.

The RM-3WE records directly in G forces and will indicate not only from which axis the force occurred but also

from which direction on that axis: left side or right side, front or back, and top or bottom (acceleration and

deceleration).

The electric chart drive mechanism allows the accelerometer to record the time, within an accuracy of

0.5 sec. per day.

Damping, other than friction (coulomb damping) must be used in mechanical accelerometers where accurate

acceleration measurement is required and where input frequencies cannot be controlled.

One example of this is monitoring rail car movement while the accelerometer is mounted directly to the car

itself.

Basically, pneumatic damping controls the performance of the accelerometer on a definite 65% of critical

damping curve will not experience resonant build-up. A friction damped unit performs on a 0.1% of critical

damping and a resonant build-up resulting in an infinite error, is possible.

APPLICATIONS

RAIL & TRUCK

Records magnitude, time of occurrence of all in-transit impacts and vibration as well as the total running and

down time of each trip.

Lateral (X) Axis records the amount of rough motion from side to side.

Longitudinal (Y) Axis records the forces involved during coupling (switching), sudden starts and stops,

“slack action”, and the condition of the draft gears.

Vertical (Z) Axis records the amount of up and down oscillation and shock that the vehicle or lading

experiences. This is an important aspect of interpreting potential damage.

Lading can theoretically leave the floor of a vehicle at any reading in excess of -1G.

X-Y-Z: the records of the three axis will indicate a combination of good or bad data, the condition of

the vehicle suspension system, excessive speeds, excessive deflection in structural systems, and the

total overall quality of vehicle handling.

PRODUCT HANDLING

Records the quality of, or lack of product handling, either manual or mechanical. When the accelerometer,

set at a comparatively low G level, is placed within a package, it will indicate which side or end the package

was dropped and when it was dropped in this position. This is helpful in determining whether or not

instructions such as “this end up” are being followed.

All records may be vectored in order to determine exact magnitude and direction of shocks to packages.

Approximate drop heights may be determined by duplicating accelerometer records in the laboratory.

LABORATORY

To correlate actual damage occurring in-transit with similar lading damage as it is reproduced on the conbur

tester, the vibration (shake table) tester and by drop tests. The instrument records the degree of severity

of package testing and thereby allows repeated test to be run on an equally severe and controlled basis.

GENERAL SPECIFICATIONS

Each accelerometer is manufactured to customer specifications. This is done by offering standard units with a

selection of G ranges from plus or minus 2G to plus or minus 50G for each axis, chart speeds of 3/8” per hour

(90 day), ¾” per hour (60 day), 1-1/2” per hour (30 day), 3” per hour (14 day), and 6” per hour (7 day),

faster chart speeds are available upon request.