MBE4000 APPLICATION AND INSTALLATION
8. Closest point x,y, z and (clearances to machine members).
9. Any external forces, such as belt and chain drives, their direction and position.
10. Any environmental conditions such as temperature highs and lows, chemical or oil
exposures, etc.
For common, non shock load applications the general procedure for self selection of mounts
has two possible methods:
□
Method A: Select a type of mount that supports the load from the supplier catalog and then
calculate its isolation capability.
□
Method B: Specify the isolation desired and calculate the mount characteristics required to
obtain this. Then select the mount from the catalog.
For more details and formulas to use in your calculations, refer to Barry Controls bulletin IOEM1,
or Lord Manufacturing bulletin PC2201o. The suitability of the selected mounts should still
be con
fi
rmed with the manufacturer. Detroit Diesel assumes no responsibility for the resilient
mounting system performance.
Method A
Select a type of mount that supports the load from the supplier catalog.
1. Determine the location of the CG of the engine and transmission package.
2. Calculate the reaction forces at each mount using the weight and the CG. Some mount
manufacturers include safety factors up to three times the mount load rating, to allow for
forces due to engine torque and rugged terrain, so weight only is normally suf
fi
cient to use
for this calculation. However, if the power package will be subject to low gear, high torque
operation, then the force due to torque must be added. Consult the manufacturer to be sure.
3. Refer to the mount tables in the catalog that suits the application and the environmental
conditions. There may be more than one suitable reference table.
4. From your table of choice, select a mount that is within the load range. There may be
several suitable mount models.
5. Using the de
fl
ection value (K) from the table or accompanying load vs. de
fl
ection charts,
and the weight (W) at the mounting point, calculate the natural frequency (Fn) of that
mount.
6. Determine what the prominent disturbing frequencies (Fi) of the input source are. The
engine is usually
fi
rst but consider other known disturbing orders as well as the terrain
(bumpy). If the engine speed varies, use the lowest speed setting as well as the normal
steady running speed. Calculate Fi/Fn. If it is greater than
the mount system is
in the isolation range. If Fi/Fn is less than
it is in the ampli
fi
cation range and may
All information subject to change without notice.
(Rev. 03/06)
11-7
7SA250 0603
Copyright © 2006 DETROIT DIESEL CORPORATION
