12v Hydraulic Pump Troubleshooting Guide: Mastering Power Unit Issues with Ease

In this complete trouble-shooting guide, we are going into the details of 12v hydraulic pump systems to examine common problems that are faced during operations. This tutorial will furnish information for experts and enthusiasts alike on how people can tell when there is trouble with a hydraulic power unit and how they can resolve the issues. The basic principles behind hydraulic systems, maintenance aspects, and techniques for finding malfunctioning parts will be considered. This article, therefore, breaks down difficult situations into simpler stages so as to facilitate an improved understanding by its readers, hence making them more competent in maintaining and fixing these kinds of machines, thus making sure of their long-lasting effect and better work done.

How Can You Identify Hydraulic Pump Problems?

To identify problems with a hydraulic pump, observe it and evaluate its performance systematically. Check the pump’s output pressure as you would note any variations or drops, which might indicate internal wear or occlusion. Moreover, listen for abnormal sounds like grinding or hissing which may mean mechanical damage or air entering the system. Further, examine for fluid leaks at any of the pump junctions as these contribute to lowered efficiency and possible system failure. Inspect the hydraulic oil for contamination that can be detrimental to pump functioning. Likewise, electrical connections should be checked to ensure they are secure while at the same time ensuring that power supply is stable since electric hitches may have serious implications on 12v hydraulic pumps.

Signs That Indicate Worn Out Pump

Various signs show a worn out pump in terms of observable behaviors and performance metrics. One main sign is the reduced efficiency of the pump, which often translates into decreased flow rates during operation and inadequacy in pressure generation. In addition, an operator may notice an increase in noise levels such as rattling or banging sound which can suggest internal components aging poorly or being out of alignment. Also critical is frequent overheating of the pump due to poor lubrication or excessive friction, which tend to increase wear. At seals or connections’ sites, fluid leakage also emphasizes deteriorating conditions inside a worn-out pump Lastly, erratic functioning and inability to uphold consistent pressure levels denotes either an already worn-out component in the hydraulic system or else one that is getting damaged by wear effects.Prompt identification of such signs allows immediate interventions, thus maintaining operational capability and expanding the life span associated with these machines.

Checking Hydraulic Fluid Levels

Checking hydraulic fluid levels regularly is essential in maintaining optimum performance while preventing system failures. First, locate where there is a fluid reservoir by checking on manufacturer-recommended indicators, which usually include dipstick/sight glass, etc.Ensure that the pump has been switched off and that the hydraulic system is depressurized before trying to access the reservoir in order to avoid any accidental injuries or damaging of the system. In case the fluid level falls under the minimum requirement, ensure that you introduce the right kind of hydraulic oil as indicated by equipment specifications. Besides that, check for discoloration, particulate, and any signs of contamination that would affect the pump’s performance and lifetime expectancy. Proper maintenance of hydraulic fluid levels will enhance system reliability and efficiency, mitigating potential issues that arise from inadequate lubrication or overheating.

Identifying Hydraulic System Leaks

Maintenance requires accurate identification of hydraulic system leaks which may lead to expensive breakages when left unattended. Carry out a visual examination of the entire hydraulic circuit, paying special attention to joints, seals, hoses, and connections areas where wear and tear are more likely to occur. Similarly, this can be seen as collecting puddles or drips beneath the equipment around these areas. Additionally, other methods, such as pressure testing or the usage of die additives, can help trace out invisible minor leakages. Listening for hissing sounds can also be a useful indicator of escaping air or fluid. Moreover, by, regularly monitoring reservoir levels while cross-checking maintenance records, it could further identify abnormal dips, possibly showing a loss in leakage situations. The importance of early detection when looking at these valves cannot be overemphasized if an efficient system is to be maintained for long periods while also adding lifetime onto those parts involved with hydraulics.

What Are Common Issues in a 12v Hydraulic Power Unit?

In a 12V hydraulic power unit, commonly found problems often involve overheating due to excessive load or insufficient fluid levels, which can limit the efficiency and spoil the system. Also, electrical faults are usually due to poor connections, cut wires, and blown fuses, among other things that make it impossible for the system to function. Besides this, hydraulic liquid contamination with moisture or debris may cause malfunctioning of the system, decrease its performance level and increase wear on its components; thus regular preventive maintenance and monitoring of fluid quality as well as electrical connections and operational parameters help to reduce these issues and ensure that a hydraulic system is operating optimally.

Troubleshooting Hydraulic Pump Failures

When troubleshooting hydraulic pump failures, it is important to consider different operating parameters and possible malfunctions systematically. One possible fault that may be observed is low inlet pressure, which indicates suction problems or blockages in the intake line that lead to an insufficient supply of fluid. For normal operation, there should be at least 10-15 psi differential between nominal inlet pressure and ambient pressure.

Additionally, discharge pressures should be checked; an abnormal discharge pressure shows internal wear due to cavitation or a damaged pump itself. Depending on applications, typical pump discharge pressures range from 500 to 3,000 psi.

The last investigation is whether the pump produces abnormal vibrations or noise indicating mechanical wear or misalignment. If vibration levels exceed 0.5 inches per second, some underlying problem could require immediate attention.

To conclude, inspecting hydraulic fluid temperatures exceeding 180°F causes fluid breakdown, leading to poor lubrication and, hence, compromising pump performance. Keeping track of these parameters vis-a-vis manufacturer specifications can facilitate early detection and prevention of potential pump failures effectively.

Solenoid and Start Solenoid Problems

Symptoms such as sporadic functioning, failure to actuate, or even total non-operation indicate solenoid issues in most cases. One of the most common among these is an electrical failure, which results from faulty wiring, damaged connectors, or a blown fuse, necessitating a comprehensive check of the electrical integrity and continuity.

Mechanical failure of the valve itself may be indicated when the solenoid is continually energized with no effect; for example sticking or binding caused by corrosion or accumulation of debris. In such cases, disassembling and cleaning or replacing the solenoid becomes necessary. The starting solenoid also malfunctions due to low battery voltage and poor grounding that prevents initiation of hydraulic systems. Many starter-related problems are resolved by ensuring that voltages remain adequate (usually above 12 volts in automotive applications) and all ground connections are properly made. Regular diagnostics and maintenance practices are essential for preemptively identifying and rectifying solenoid-related problems.

Dealing with Air Leaks in the System

Hydraulic performance can deteriorate significantly when there is an air leak in this system, making it erratic and less effective. Solving air leaks entails a careful approach: initially, one should visually inspect all hoses, fittings as well as seals connected to the hydraulic system for any visible signs of tear or wearing out completely. Consequently those areas where high pressure exists like quick connect fittings and ports must be carefully checked due to their vulnerability to leakage compared to others..

Other than that, using a soapy water solution and testing for leaks will be useful; any bubbling means air is escaping. To avoid excessive wear or impairment, the technical parameters under observation include system pressure, which should ideally be maintained as stipulated by the manufacturer. Depending on system design, typical operating pressures may range from 1,500 to 3,000 PSI.

Whenever you detect them, it becomes very important to attend to air escapes immediately by tightening fittings, replacing worn-out seals, or, in some cases, using hydraulic sealants. This will help prevent further leakage throughout continuous upkeep and regular checks of the system, thereby maintaining its optimum functionality.

How to Properly Maintain a DC Power Unit?

Reliability and durability of a DC power unit depend on its proper maintenance. Always inspect all electrical connections for corrosion and tightness, as loose or corroded terminals can cause voltage drops or system failures. Furthermore, it is important to check battery electrolyte levels in lead-acid cells and topped up with distilled water whenever necessary so that low levels will not damage them. Regular cleaning of the terminal areas helps prevent dirt build-up that may affect performance.

Moreover, monitor the temperature of the unit as excessive heating might be indicative of some difficulties beneath. It is advisable to have a routine testing program for both load and voltage so as to keep the unit within stated parameters. In case there are any cooling fans or vents in the power unit, they should always be clear from obstruction for smooth airflow. Lastly, go through the manufacturer’s guidance on planned maintenance actions, including specific component inspections and replacement intervals for optimum functionality and safety.

Regular Reservoir and Pump Maintenance

Reservoirs and pumps must be maintained regularly for hydraulic systems to perform at their best. To begin with, regularly check reservoirs for contaminants, including dirt or moisture, which could compromise fluid quality. A replacement schedule established based on manufacturer recommendations can be used alongside operating conditions in order to maintain optimum lubricant properties. There is also a need to inspect components of the pump, like seals and bearings, to prevent leakage due to wear, resulting in a loss of efficiency.

It is important to monitor pump performance and look out for any abnormal vibrations or sounds since these might indicate mechanical problems. Additionally, regular testing against specified performance criteria enables early detection of deviations in flow rates and pressures exhibited by pumps within acceptable limits prescribed by manufacturers as well as other sources identifying potential discrepancies before they become major challenges. Moreover, if one wishes an uninterrupted flow, it requires that he keeps filters clean, hence removing debris together with particles continuously, thereby keeping off damages from that system; this means keeping strainers clear from obstructions throughout.

A comprehensive record of maintenance activities will aid in trend analysis and identification of any reoccurring problems, enabling proactive adjustments to maintenance strategies.

Tips for Adjusting the Relief Valve

There is a need for accurate adjustment of relief valve to suit its purpose as specified by the manufacturer. First, consult the technical manual of the manufacturer concerning model-specific relief valves because this documentation provides crucial parameters such as pressure setting ranges and adjustment procedures. Normally, the following steps can be used:

1. Determine the System Pressure: Check the system pressure using a calibrated pressure gauge before making any adjustments. This establishes a baseline at which the required settings for the relief valve can be computed.
2. Adjust the Set Pressure: Most relief valves have an adjusting screw or knob. To increase set pressure, turn screw clockwise; to reduce set pressure, turn it counter clockwise. It is wise to make small increments, typically 5-10 psi adjustments, before another reading of system pressure.
3. Test the Valve’s Response: After each adjustment, it is important to verify that it opens at pre-determined pressures by gradually increasing the system’s pressure while observing whether the relief valve operates properly.
4. Check for Internal Leaks: Monitor any leakage during valve operation which indicates further need for tuning or replacement of internal parts
5. Keep a record of all adjustments made: To assist in future repairs and maintenance, all changes should be well-documented, detailing initial and last settings.

Manage Viscosity of Hydraulic Fluid

Maintaining viscosity of hydraulic fluid is very important in order to achieve efficient system performance, as well as prolonging the life expectancy of hydraulic parts. Viscosity which means how thick or thin a liquid is, affects lubricating and heat transfer properties within the hydraulic system. It is, therefore, important to choose fluid with the right viscosity grade that matches the application’s operating temperature range. The fluid’s viscosity on the other hand must remain constant amidst varying pressure and temperature conditions so as to avoid cavitation and wear-out of hydraulic components.

Viscosity monitoring should be done regularly. This can be done by using a viscometer or referring to technical information on a fluid data sheet. If it deviates from recommended levels, there might be a need for changing the fluid or adding some viscosity modifier. Besides this, these additives help enhance lubricity while reducing oxidation rates, aiding in maintaining uniform consistency over time. Establishing regular service based on viscosity performance will enhance optimal functioning and reliable hydraulic systems.

How Do You Address Hydraulic Pressure Concerns?

Addressing concerns about hydraulic pressure needs a systematic approach that includes monitoring, adjustment and maintenance. First of all, it is important to regularly measure the pressure in the system with calibrated gauges so as to ensure that operational parameters are within the required range. If readings are consistently outside this range, then there may be leakages or blocks in the system, which could have an effect on pressure dynamics.

Adjusting pressure occasionally demands adjustments on the relief valves (or) checking valves being made to ensure they are in good working condition, thus preventing over-pressurization, which may cause catastrophic failures. It is also essential to ensure that hydraulic fluid is maintained within the appropriate viscosity specified earlier because wrong viscosity leads to fluctuations of pressure. Lastly, routine maintenance, including changing worn-out parts and regular changes of fluids, helps preserve the best possible pressure levels and ensures the reliability of hydraulic systems.

Verifying Pressure at the Pump’s Outlet

Verification of pump outlet requires careful measurement using calibrated pressure gauges. The outlet pressure should not exceed psi (pounds per square inch) or bar values specified by manufacturers. For instance, an ideal output pressure for a typical hydraulic pump could be 2000 psi.

Procedure for verification:

1. Safety Precautions: Ensure safety measures are put in place prior to proceeding with no accidents or equipment damages occurring.
2. Gauge Calibration: Employ a calibrated gauge to avoid inaccurate results due to disparities that might arise as a result of faulty instruments used
3. Installation of Gauge: Connect it with outlet port on pump while taking care not strain it so hard leading into leakages.
4. Operational Conditions: Allow time for stabilization by running the pump under normal conditions
5. Recording Measurements: Several readings must be taken, accounting for normal dynamic changes, for proper pumping operation. Consistent readings within given limits verified this.
6. Analysis of Readings : Moving below/above acceptable parameters will mean investigations are needed as pump wear, wrong settings or hydraulic circuit issues can be behind it.

Using a Pressure Gauge

To use the gauge correctly, one must know how it works and what its various parts are. The standard pressure gauge consists of three main components: a sensing element that detects pressure, a display that may be digital or made up of numbers on the dial and casing that houses everything else. The first step towards using this device is ensuring that calibration has been done accurately so as to allow precision in reading out pressures. While attaching the gauge to the system’s point of pressure, ensure proper fitting for leak free readings. When ready connect to the system in order to initiate the flowing of fluid under pressure. Observe and interpret current results in relation to set operational parameters by the manufacturer of equipment with regard to attached gauges’ displays, which will show real-time force applied within the system at that given instance. Lubricating oil should not be taken more than 0.7 years.Being familiarized with these indications helps predict the time when servicing is required.As such, routine check-ups and maintenance have a major impact on its lifespan expectancy for accuracy measurements during practical use.

Inspection of High Pressure Components

The operation of any arrangement should be safe and productive after inspecting the high-pressure equipment. Everything should be checked for wear, corrosion or physical damage through visual inspection, especially in areas of stress and fatigue. Leaks and accurate seatings should be searched for in high pressure seals as they can cause a sudden failure when they are not sealed properly. Tests such as ultrasonics or radiographic methods that do not destroy the material to evaluate integrity of the material before it is destroyed by any test could be employed. All components must conform to prescribed industrial standards and manufacturer specifications. Besides, keeping inspection records helps in identifying component trends and establishing preventive maintenance programs.

What Steps Are Essential in Power Unit Troubleshooting?

1. First Assessment: Commence by gathering information about the signs of a problem. Note down any error codes, abnormal noises or unusual performance indicators that have been identified.
2. Eye Examination: Conduct an exhaustive visual examination of the power unit with special focus on leakages, loose connections and breakages to see if there are visible problems that can be solved easily at this stage.
3. Check Electrical System: For continuity, test electrical connections and wiring harnesses to ensure they are intact and free from rusting; for which you may use a multimeter to test voltage and current levels in relation to manufacturer’s specifications.
4. Functional Testing: Carry out functional tests on major machine parts such as motors, controls, and sensors, among others, by running the power unit under controlled conditions while collecting vital performance statistics.
5. Data Analysis: Use diagnostic tools and applications to analyze data recorded in the unit’s control system. This helps find faults by comparing actual performance against expected operational parameters.
6. Replace or Repair: Depending on findings from earlier stages, eliminate all defective components; but make sure that replacements have been done according to manufacturers’ specifications.
7. Final Verification: After repairing the power unit, confirm through testing that it is functioning correctly and efficiently before documenting the troubleshooting process and outcomes for subsequent reference purposes.

Manufacture’s Troubleshooting Guide

1. Symptom Identification: Clearly state the symptoms exhibited by the malfunctioning power unit matching them up with possible issues listed in the manufacturer’s guide?
2. Referring Specific Error Codes: Look at error codes related to its particular condition stated in their guide book; where these could be crosschecked with displayed signs of brokenness,
3. Using Recommended Diagnostic Tools: systematically follow the diagnosis steps given by the manufacturer to determine the system condition, including using custom software or physical test equipment as provided in their literature.
4. Use Recommended Methods: Follow guided steps such as inspection, testing, repair, and verification as stated in the troubleshooting guide, ensuring all actions are carried out according to the manufacturers’ specifications.

Steps to Bypass Hydraulic Circuit Issues

1. Circuit Inspection: Begin by comprehensively evaluating the hydraulic circuit to identify potential blockages or faults. Use tools like pressure gauges and flow meters to measure operational parameters and identify issues.
2. Find the Faulty Section: Once you have identified where the problem lies, isolate it from other parts of the circuitry. This may mean shutting off certain valves or disconnecting hoses that would further complicate things during bypassing.
3. Formulate Bypass Configuration: Before ducting hydraulic fluid around the faulty segment, provide a channel for its passage, hence avoiding interference with any other point causing harm, especially by using suitable pipes and fittings that match liquid compatibility requirements and also have a maximum pressure capability.
4. Test and Fix It Securely: Ensure every connection is tight to evade leakage problems. After establishing yourself, run some system tests to see if there is anything wrong with flow or pressure, indicating that requirement adjustments are needed.
5. Record Changes: During this bypass process, document all changes made, including diagrams and specifications, so that subsequent maintenance can refer to modifications made while understanding the current layout.

Making Sure the Rotation is Properly Directed

To ensure hydraulic applications rotate in the right direction, all components, such as pumps, motors, and actuators, should be properly aligned with their intended flow directions. First of all, go through the manufacturer’s documentation for each component, which often explains the correct rotation direction. Also, use visual identification methods like marking or labeling to determine the orientation of both drive and driven components. Moreover employ diagnostic instruments like tachometers to measure actual rotation when system is operational. In case there are rotating differences check wiring connections and control signal configurations for electrical components so that they are configured to deliver the right phase and polarity. The routine maintenance checks should also involve visual inspections of signs of wear or damage that could possibly affect rotation direction, hence enhancing the reliability and efficiency of the hydraulic system.

How Do You Prevent Contamination in Hydraulic Systems?

It is vital to maintain performance and lifespan by preventing contamination in hydraulic systems. Firstly, ensure cleanliness while installing or maintaining it, using clean tools and materials. Put filters at key points in the system to get rid of particulate matter and moisture prior to their entry into vital components. Inspect and change filters as required by manufacturers to achieve the best filtration efficiency. In addition, seal all possible infiltration areas such as hose connections or reservoir openings against airborne elements that contaminate this fluid. It would also be wise to have routine oil analysis done; for early detection of contamination in order to take prompt action when appropriate. Finally, training staff on safe handling practices for hydraulic fluids and prevention of human-induced pollution becomes instrumental.

Control Valve Cleanliness

Hydraulic systems are highly dependent on the cleanliness of control valves as a factor for proper functionality and durability. If contaminated, these parts may not move smoothly or, at times, fail to perform well, causing a total failure of the entire system. Use only high-grade hydraulic oils free from impurities as stipulated by their manufacturers so as to avoid counteracting this cleanliness requirement for smoother operations With regard to valve installation, keep off any form of debris and loose particles from surrounding areas where these valves would be placed. Provide the right solvents that do not leave any residues after cleaning so that those affected will detach them apart for examination purposes.The other way is through proper storage practices with respect to both valves themselves and general control mechanisms, including sealing them off whenever they are not being used, hence protecting them from contaminated environments.Thus, teaching operators the principles governing maintenance (cleaning) operations also helps engineers’ decisions related to reliability.

Monitoring Fluid Contamination Levels

Monitoring fluid contamination levels plays a crucial role in maintaining good health and performance of hydraulic systems. Routinely evaluating hydraulic fluid cleanliness can be accomplished using various methods such as visual examination, particle counting ,and chemical analysis

Visual inspection entails looking for changes in the appearance of the fluid and particulate contamination. Particle counting, which involves quantifying the volume and size distribution of particles within hydraulic fluids by laser, is an excellent measure for assessing fluid contamination levels. Spectrometric and chromatographic methods are employed to identify specific impurities or degradation products that demand appropriate actions.

To ensure effective monitoring, it is advisable to establish a baseline for acceptable contamination levels based on the manufacturer’s specifications and industry standards. Scheduling routine tests for fluid cleanliness at fixed time intervals or immediately after significant operational modifications helps in identifying trends over time. Implementation of automated monitoring systems can enhance real-time awareness, enabling prompt responses to contamination events. Consistent analysis not only extends hydraulic component life but also improves overall system reliability and efficiency.

Preventing Corrosion in Hydraulic Components

Corrosion significantly threatens the integrity and performance of hydraulic components.To reduce this risk, several approaches should be taken. Firstly, choosing the right hydraulic fluid is vital since there are oils that contain anti-corrosive additives that form a layer against moisture as well as contaminants, hence reducing the chances of corrosion. Adhering to recommended coolant volumes while ensuring proper seals prevents water from entering into a system, thus starting off corrosive reactions.

Secondly, regular monitoring and maintenance practices are essential. This includes fluid analysis and the inspection of components for signs of rust or degradation.Routine cleaning combined with periodic replacement of worn-out parts will significantly minimize corrosion risks.

Finally, protective coatings are a significant factor in boosting resistance against environmental agents of corrosion. They serve as physical barriers, blocking corrosive elements from reaching metallic areas. Hence, the above-discussed factors should be considered to prevent corrosion in hydraulic systems and increase their longevity.

Reference sources

1. Northern Hydraulics
   • Source: Troubleshooting DC Hydraulic Power Unit
   • Summary: This guide provides extensive troubleshooting steps for DC hydraulic power units, including checks for sufficient volts/amperage and inspecting the condition of all wiring to ensure proper motor engagement.
2. KTI Hydraulics Inc.
   • Source: DC Power Unit Troubleshooting Guide
   • Summary: The guide covers common issues related to directional valves, electromagnetic coils, O-rings, and debris in valves. It offers clear instructions for diagnosing and addressing these problems to maintain optimal pump performance.
3. Plant Services
   • Source: Troubleshooting Electro-Hydraulic Pumps: A 12-Step Program
   • Summary: This article outlines a comprehensive 12-step program for troubleshooting electro-hydraulic pumps, detailing checks for pump speed, direction of rotation, operating temperature, and pilot pressure to identify and resolve common operational issues.

Frequently Asked Questions (FAQs)

Q: What are the common causes of a 12v hydraulic pump failing to energize?

A: Common causes include insufficient oil level, faulty hydraulic pump shaft seal, blown circuit breaker, and issues within the flow control system. Always check the oil level and circuit breaker first, ensuring they meet the manufacturer’s specifications.

Q: How do I check if there is air in the system?

A: To check for air in the hydraulics system, operate the pump and listen for an unusual noise or cavitation. You can also observe the hydraulic fluid for bubbles. If air is present, you’ll need to bleed the system according to the manufacturer’s instructions.

Q: What should I do if the pump housing is excessively hot?

A: Excessive heat in the pump housing could indicate a maximum load condition or restricted flow. Check for restrictions in the hydraulic lines and ensure the oil level is correct. If the problem persists, investigate the possibility of internal pump problems or excessive pressure.

Q: Why is the hydraulic system not retracting properly?

A: If the hydraulic system isn’t retracting properly, the spool may not be shifting as it should. Verify that the spool in the flow path can move freely and check for restrictions or debris that might be obstructing the flow control. A detailed inspection of the retract mechanism might be necessary.

Q: How can I prevent oil leakage in my hydraulic pump?

A: Regularly check the shaft seal and replace it if there’s wear or damage. Ensuring the pump shaft alignment is within tolerance and avoiding overpressure situations can also prevent oil leaks. Monitor seals and replace any that show signs of wear as part of routine maintenance.

Q: What steps should I take when cavitation occurs?

A: When cavitation occurs, first check the oil level and make sure it’s adequate. Inspect the pump housing for any indications of wear. Check for excessive air in the system and ensure there are no restrictions in the suction line. Corrective action might include reducing inlet restrictions and ensuring an adequate oil supply and correct viscosity.

Q: How do I diagnose issues with the dc hydraulic power unit?

A: Start by consulting the schematic to understand the system layout. Check the amperage to ensure it’s within the specified range. Evaluate the maximum pressure settings, look for signs of wear in the pump shaft, and examine the circuit breaker for faults. Corrective action should be based on these diagnostic findings.

Q: What does it mean if there is a significant drop in gpm output?

A: A significant drop in gpm output usually points to issues within the pump or the hydraulic circuit. Possible reasons include a worn pump shaft, clogged filters, or restrictions in the hydraulic lines. Checking the oil level, pressure port, and flow path for obstructions can help identify the cause.

Q: How often should I check the manifold and case drain?

A: Regular maintenance of the manifold and case drain should be performed in accordance with the manufacturer’s recommended schedule. Typically, this involves checking for leaks, ensuring proper seals, and replacing any worn components. Regular inspections help maintain optimal performance and prevent extensive wear.

Q: What is the importance of the pump shaft coupling?

A: The pump shaft coupling is crucial for transferring power from the motor to the pump. Any misalignment can cause undue wear, noise, and vibration. It’s important to ensure that the coupling is properly aligned and securely attached to prevent shaft and gear damage.