How to troubleshoot the failure of starting the oil and gas recovery equipment? Direct answer: Check from the periphery to the core in order - on the power side, check the air switch and fuse in the distribution box; on the control side, check the emergency stop button and interlock signal; on the core side, check the controller status and executing components. Most startup failures occur in the first two levels, and the actual burning of the motor is rare. Without complex equipotential instruments on site, the first two levels of troubleshooting can be completed using a multimeter and observing indicator lights. If a problem is found at this level, deal with it at this level. For cross-level issues, contact the manufacturer. Bringing records when reporting the repair can save a lot of back-and-forth. This article clarifies the order and key points.
General investigation sequence: from the outside to the inside
The design logic of the sequence follows a cost-inversion approach: the more peripheral checks are simpler and safer, while the closer to the core, the more instruments and experience are required for judgment. Troubleshooting begins with the power supply, checking the indicator lights on the distribution box, the position of the air switch, and the status of the fuse; then it moves to the control, checking whether the emergency stop, door limit, and process interlock signals are in place; next, it focuses on the controller, checking the power-on self-test, fault codes, and output indications; finally, it examines the end-point execution components, checking whether the motor, pump, and valve are stuck. The disadvantage of skipping levels is misjudgment: if the controller reports an overload, the root cause may simply be a stuck valve, and directly replacing the controller would be both costly and ineffective in solving the problem. Following the sequence, each level of troubleshooting has a basis.
What should be checked on the power supply side
When examining the power supply side, focus on four points: whether the main air switch of the distribution box is in the closed position, whether the branch air switches have tripped, whether the fuses are blown, and whether the voltage is within the required range for the equipment. After a trip, do not rush to close it immediately. First, test whether there is a short circuit on the insulation and load sides. Repeatedly forcibly closing the switch can expand the fault area. Phase loss is a hidden killer: when one phase of three-phase power is missing, the motor will only hum and not rotate. After a short period of time, the windings will burn. If you smell a burning odor or hear continuous humming, you must immediately power off. Low voltage can also cause insufficient starting torque, manifested as tripping immediately after engagement. This is especially common in sites with long-line power supply. By comparing the voltage at the beginning and end, you can confirm this issue.
What is the focus of control and interlocking inspection
Control side view emergency stop and interlocking: If the emergency stop button is pressed and not reset, the maintenance door limit is not in place, or the process interlocking conditions are not met (such as upstream valves not being opened, tank pressure not within the starting range), the starting circuit will be disconnected. The common feature of such issues is that the indicator light status does not match the on-site action: the panel displays ready, but pressing the start button has no response, most likely because a certain interlocking condition has not been met. Checking the interlocking list one by one is more efficient than making global guesses. Before checking buttons and junction boxes in explosion-proof areas, confirm that the power is off, open the junction box cover, and follow hot work management procedures. Do not disassemble them in an oil and gas environment without protection.
Controller and execution component
After the controller is powered on, check the self-test process: if the screen cannot enter self-test, check the power supply and communication lines; if the self-test stops at a fault code, refer to the manual to understand the meaning of the code. Common issues such as overload, phase loss, and communication interruption are clearly indicated. Use a multimeter to measure the output side to see if the start command is sent to the contactor coil. If there is a command but no action, it is a problem with the contactor or wiring. If there is no command, it is a problem with the controller or input circuit. Check the execution components at the end: whether the motor barring gear is stuck, whether the pump body is blocked by crystallization, and whether the valve is stuck due to rust or condensate adhesion. Before dismantling and inspecting the execution components, power off and tag out. After restoration, jog the rotation direction first, and then proceed to continuous operation.
Inspection records and repair requests
| Investigation level | What are you looking at? | Common root causes | Can it be handled on-site |
|---|---|---|---|
| Power stage | Air switch safety voltage | Trip phase loss and low voltage | Most can be handled on-site |
| Control level | Emergency stop interlock signal | Emergency stop not reset, interlock missing condition | Can be processed on-site |
| Controller level | Self-check fault code output | Overload communication interruption | Dispose according to the code |
| Execution level | Motor pump body valve | Stuck, crystallized, and rusted | "Need to be dismantled and inspected before listing" |
Troubleshooting steps
- Check the air switch and fuse in the distribution box when it is powered off;
- Restore the voltage at the starting and ending points of the power supply test;
- Reset the emergency stop and verify all interlocking conditions;
- Observe the controller self-check and fault codes;
- Measure whether the start command has reached the contactor;
- Check the motor pump body and valve during the turning gear inspection.
Frequently Asked Questions
Can a circuit breaker be forcibly closed after repeated tripping?
Do not: Tripping is a protective action. Forcing a reclosing before the root cause is resolved can escalate the fault, potentially causing damage from the air switch to the cable and even the motor. First, test for insulation and short circuits on the load side. Ensure there are no issues before reclosing. After reclosing, monitor the operating current.
What should I do if the fault code reappears after being cleared?
The root cause remains to be identified: review the corresponding circuit according to the code indication, and record the operating conditions at the time the code appears - current, pressure, temperature, and action sequence. These records serve as the basis for diagnosing intermittent faults and are also the information required by the manufacturer when a repair is reported.
Is there an emergency solution for starting issues during the night?
Emergency response with prerequisites: After confirming that the power supply and interlocking are normal, switch to manual mode according to procedures to maintain minimum load operation, and arrange for a supplementary inspection during the day. Do not forcefully open in explosion-related areas and situations with excessive emissions. Emergency response should be based on safety and compliance, and the situation should be documented and handed over to the day shift.
This article is compiled by Luoyang Wohong Petrochemical Equipment Co., Ltd. The company provides design and manufacturing, skid-mounted customization, installation and commissioning, as well as after-sales operation and maintenance services for three-time oil and gas recovery equipment to gas stations and oil depots. If you need on-site inspection or scheme configuration, please feel free to contact us for discussion.