Doosan heavy-duty machines are renowned for their exceptional performance and durability in various industries. To ensure optimal functioning, regular maintenance is crucial. One vital aspect of maintenance is the calibration of the Variable Back-Off (VBO) system, which requires a thorough pump EPPR valve check. In this article, we will guide you through the step-by-step process of conducting this essential inspection.
Preparations:
Doosan Data Monitoring System DMS-5 DMS-3 Free Download
Doosan Diagnostic Tool
Pump EPPR valve check
*Calibration judgement
3.1. Measure the input & output current of the pump EPPR valve in certain condition
Ex. DX350LC-7, Normal outputs of pump EPPR valve (Please refer the shop manual to check the exact value
on each model)
Not in operation: 300 ±30 mA
Pilot operation: up to 750 ±30 mA
Relief pressure up operation: 800 ±30 mA
3.2. Check the physical condition of the EPPR valve
3.2.1. Assembly condition
3.2.2. External damage
3.2.3. Short circuit
Ex. DX350LC-7(Please refer the shop manual to check the exact value on each model)
3.3. Measure the resistance of the EPPR valve
3.3.1. Measure the resistance of the valve coil: If the measurement is infinite, this indicates an
open circuit of the coil in the valve.
3.3.2. Measure the resistance of the valve coil: If the measurement is 0Ω, this indicates a short
circuit of the coil in the valve.
More topics for Doosan,please refer to: Doosan Trouble Repair
Conclusion:
Regular maintenance, including the calibration of the VBO system, is vital for the optimal performance and longevity of Doosan heavy-duty machines. The pump EPPR valve check is an integral part of this maintenance routine. By following the step-by-step guide provided in this article, operators can ensure that the EPPR valve operates smoothly and efficiently, contributing to the overall reliability and productivity of the machine.
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