Usage:
BG-2455C (6TN, ACM) ASPHALT PAVER
Problem:
The problem becomes worse as the machine warms up. This typically occurs at speeds above 100 fpm in the pave mode and is not usually evident in the travel mode. The problem can be identified by measuring the current going to the suspected EDC. If the machine pulls to the left during forward travel, place the meter in series with the left forward EDC. With the machine oil temperature under 100°F, run the machine at maximum pave speed. The meter should read between 83 and 92 mA. Now warm the machine up. If there is a PCP problem, as the machine warms warms up, the current at maximum speed will increase. If the current reaches 100-103 mA, the machine will start to pull. As the machine temperature increases, the speed at which the current reaches 100-103 mA will decrease and the machine will start to pull at lower speeds.
The chart above is taken from an AP-1055B that is initially traveling straight. Notice that before 203 seconds, the Left and Right Desired Motor RPM, Left Motor RPM, and Right Motor RPM are the same. Also, before 203 seconds the right EDC current is 64 mA and left EDC is 96 mA.
At 203 seconds the desired speed increases. This causes the EDC currents to increase to 68 mA on the right EDC and 100 mA on the left EDC. The increase in EDC current causes a corresponding increase in left and right motor RPM. The left and right motor RPM are very close up to 213 seconds, this indicates the paver is traveling straight.
At 213 seconds there is another increase in desired speed. This desired speed increase causes an increase in right EDC current to 72 mA and a corresponding right motor RPM increase to 2660. The desired speed increase does not create an increase in left hand EDC current because the current is already at the maximum of 100 mA. Due to this, the left motor speed becomes less than the desired speed and less than the right motor speed. This indicates the machine is drifting or pulling to the left.
At 231 seconds there is another increase in the left and right desired motor speed. This causes an even larger difference in the left and right motor speeds. On the machine this would be seen as a harder drift or pull to the left.
Following are the EDC wire numbers and pin locations:
Solution:
Remove the suspect EDC and replace the 1G-9335 PCP with a PCP having a date code of 9834 or later. The date code is stamped in the aluminum block opposite the side with the wires. Reinstall the EDC and mechanically null it. Perform propel calibration C12 and retest machine performance.
The solution is effective with AP-1055B (8BM00122-00425) and BG-2455C (6TN00115-00142, ACM00246-00247).
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