CEMB USA ER100-i (B) - Manual (Page 57)

57
Use and Maintenance Manual Rev. 12-2012
ENGLISH
Decreases the value
Increases the value
Confirms the default parameters
Goes back to the main menu screen
Goes to the setup screen 2/3
Return to main screen
Setup
BPC (Best Possible Correction) Provides the best possible solution for reduction of vibrations noticeable in the
vehicle.
Many elements affect the vibration perceived in the vehicle due to wheel unbalances:
▪ Residual static unbalance
▪ Residual dynamic (or torque) unbalance
▪ Wheel weight (the heavier the wheel, the less the unbalance will make it vibrate)
▪ Wheel diameter (on which the application radiuses of the counterweights depend)
Comparison between conventional balancing and the BPC method
CONVENTIONAL BALANCING:
▪ Given a set tolerance of 5g, a wheel is considered balanced also with a residual unbalance of 4.9g per plane in
approximately the same angular position. This means that a static unbalance of 9.8 grams is tolerated, even
though the static unbalance is deemed the main cause of vibrations noticeable by the driver.
▪ The balancing tolerance for all wheel types, not taking any unbalance of 10g into account, produces different
vibrations on a 13” or a 22" wheel. The residual vibrations are inversely proportional to the wheel weight.
▪ The angular position of the residual unbalances is not taken into account.
BALANCING USING THE BPC METHOD:
▪ With this method, the balancing tolerance value is reprocessed based on the wheel dimensions and the permissible
residual static and torque unbalances, which are numerically different (greater torque unbalance than static
unbalance is permitted).
▪ The tolerance no longer refers to the correction planes but is UNIQUE and indicates the residual vibration limit
value permissible on the wheel.
▪ An indicator on the screen provides information on the residual vibration obtained after balancing with respect
to the maximum tolerable vibration.
▪ Bymeans of complex mathematical calculations, it indicates how many and where correction weights should be
added for the best possible reduction of the vibrations noticeable by the driver. This means that the customer
receives the best possible service.
No alternative method can be more accurate, using moderate weights with steps of 5g.
The machine also measures by HOW MUCH the “noticeable vibration” in the vehicle has been reduced with respect to the
conventional method, indicating the percentage reduction, i.e. by how much it has improved with respect to conventional
machines.
Less vibration, more satisfied customers!
Display pitch: This represents the unbalance display pitch and varies based on the unit of measure
selected. Selecting 5g (1/4 oz) enables display of the correction values on the two sides
such as to set the static unbalance value to 0 (theoretical).
It is advisable to set this function for normal use of the machine, as it improves the bal-
ancing quality. The computer makes a complex calculation which allows cancelling the
residual static unbalance by varying the value and the position of the counterweights fixed
in steps of 5 grams (1/4 oz).
Tolerance: This is the unbalance threshold below which OK appears on the screen instead of the
unbalance value at the end of the spin.
Default parameter setting: Resets the default machine settings.