Troubleshooting: Noises and abnormal vibrations in gearboxes

1. Description of the problem and scope of application

This manual is designed to provide technicians and maintenance engineers with a systematic approach to diagnosing and troubleshooting abnormal noise and vibration in industrial gear units. Identifying the source of noise and vibration at an early stage is critical to preventing catastrophic failures, minimizing downtime, and extending equipment life.

1.1. Symptoms covered in this guide

• Noises: Includes rumbling, screeching, howling, banging, popping, clicking, squealing, or buzzing sounds that differ from the normal operating sound of the gear.
• Abnormal Vibrations: Rotational vibrations exceeding established tolerances are often manifested as an increased level of vibration, changes in the frequency spectrum, or displacement of the axis of rotation.

1.2. Equipment types covered

This manual applies to a wide range of industrial gearboxes used in metallurgy, mining, energy, chemical and mechanical engineering. These include, but are not limited to: cylindrical, bevel, worm, planetary, and helical-bevel gearboxes. Regardless of the specific type, the basic principles of noise and vibration diagnostics remain consistent.

1.3. Classification of severity

• Critical failure: Immediate risk of catastrophic failure that could result in significant equipment damage, personnel injury, or prolonged production downtime. Requires immediate equipment shutdown.
• Serious Fault: Potential risk of significant damage if the problem is not resolved within a short period of time. May result in reduced component life. Requires planning for repairs.
• Minor malfunction: A malfunction that does not pose an immediate threat, but may indicate the initial stages of wear or small deviations from the norm. Requires monitoring and scheduled maintenance.

2. Precautions

Safety is critical when diagnosing and repairing industrial equipment. Failure to follow these instructions could result in serious injury or death. Always follow local regulations and equipment manufacturer's instructions.

• Use personal protective equipment (PPE): Always wear safety glasses, safety gloves, safety shoes, and hearing protection when working around gears.
• Lockout/Tagout Procedures (LOTO): Before performing any diagnostic or repair work, be sure to de-energize the equipment and apply lockout/tagout procedures in accordance with DSTU standards EN 1037 and internal company procedures. Check the absence of voltage with the help of appropriate devices.
• Stored Energy Warning: Some gearboxes may have stored energy (eg in springs, hydraulic systems, rotating masses). Make sure all stored energy is discharged or blocked before starting work.
• Dangerous Conditions During Diagnostics: There is a risk of contact with moving parts, hot surfaces, or electrical current when operating noise and vibration diagnostic equipment. Perform work with extreme caution and only with appropriate permission and training.
• Hazardous substances: Lubricants and other liquids may be hot or contain hazardous components. Use appropriate containers and PPE for handling them.

3. Necessary diagnostic tools

A set of specialized tools is required for effective diagnosis of gearbox noises and vibrations. Ensure all instruments are calibrated and in working order.

4. Initial evaluation checklist

Before starting a detailed diagnosis, perform an initial visual inspection and collect information. This will help narrow down potential causes and ensure safety.

5. Systematic diagnostic algorithm

This algorithm provides a step-by-step approach to identifying the root cause of noise and abnormal vibrations in gearboxes. Follow him consistently.

1. Initial Assessment and Security:
   1. Ensure Security: Ensure that all precautions described in Section 2 are followed.
   2. Perform an initial review: Perform the checks per the "Initial Evaluation Checklist" (Chapter 4). Record all deviations.
   3. Determine Severity: Based on initial observations, classify the fault as Critical, Major, or Minor.
   4. If a critical malfunction: Immediately stop the equipment, block/tag out. Go to detailed diagnostics in stopped state.
2. Diagnostics during operation (if safe):
   1. General vibration analysis:
      1. Use the vibration analyzer (Chapter 3) to measure vibration on the gearbox housing in three directions (vertical, horizontal, axial) at key points (input shaft, output shaft, bearing assemblies).
      2. Record the root mean square (RMS) vibration velocity (mm/s) and vibration acceleration (G).
      3. Compare with acceptable standards: Refer to ISO 10816 standards (eg ISO 10816-3 for industrial machines) or manufacturer recommendations.
      4. IF the overall vibration level EXCEEDS the permissible limits (eg >4.5 mm/s RMS for class III): Proceed to frequency spectrum analysis.
      5. IF overall vibration level NORMAL, but noise is present: Proceed to localize the noise with a stethoscope.
   2. Vibration frequency spectrum analysis:
      1. Use the vibration analyzer to obtain the frequency spectrum at the measurement points.
      2. Determine the characteristic frequencies:
         1. Rotational frequencies of the shafts (1x, 2x, 3x rpm): Usually indicate imbalance, misalignment, loosening of fasteners.
         2. Gear mesh frequency (GMF) and sidebands: Indicates gear defects (wear, pitting, cracks). GMF = (Number of teeth) x (Speed ​​of rotation of the shaft).
         3. Bearing Frequencies (BPFI, BPFO, BSF, FTF): Specific frequencies calculated based on bearing geometry and rotational speed indicate raceway, rolling element or separator defects.
         4. Sub-Synchronous/Semi-Synchronous Frequencies (<0.5x об/хв): May indicate lubrication problems or shaft instability.
      3. Interpretation: Compare the detected peaks with standard tables of characteristic frequencies for the reducer.
      4. IF detected peaks corresponding to gear frequencies: Go to gear diagnostics (paragraph 3.1).
      5. IF detected peaks corresponding to bearing frequencies: Go to bearing diagnostics (paragraph 3.2).
      6. IF detected peaks corresponding to the rotation frequencies of the shafts or their harmonics: Proceed to the diagnosis of misalignment/imbalance/weakening (clause 3.3).
   3. Locating the noise with a stethoscope:
      1. If the vibration is normal, but the noise is present, use a mechanical or electronic stethoscope to locate the source of the noise on the gearbox housing.
      2. Listen to different points: input shaft, output shaft, bearing assemblies, connections.
      3. IF the noise is localized in the area of the bearing unit: Go to the diagnosis of the bearings (item 3.2).
      4. IF noise seems general or comes from gears: Proceed to gear diagnostics (paragraph 3.1).
   4. Thermal Imaging/Pyrometry:
      1. Use a thermal imager or pyrometer to scan the gear housing, bearing assemblies, and seals.
      2. IF Abnormally high temperatures are detected (>80°C or significantly above the base temperature by 20°C): This indicates excessive friction, lack of lubrication, overload or bearing failure.
      3. Record the temperature map. This can help in localizing the source of the problem (for example, overheating of one bearing).
3. Diagnostics in a stopped state (after blocking/marking):
   1. Lubricant analysis:
      1. Take a sample of the lubricant according to DSTU ISO 4405.
      2. Send the sample to the laboratory for a comprehensive analysis, which includes:
      3. Viscosity: Tested to meet specifications (ISO VG). A change in viscosity may indicate lubricant degradation or contamination.
      4. Water content (%): The presence of water accelerates wear, causes corrosion and reduces the bearing capacity of the lubricant. Permissible level: <0.05%.
      5. Number of metal particles (ppm): Iron, chromium (wear of gears, bearings), copper, lead (wear of bearing separators, bushing).
      6. Acidity index (TAN): An increase indicates oxidation of the lubricant.
      7. Ferrography analysis: Determination of the type and size of wear particles (normal wear, abrasive wear, pitting wear).
      8. IF grease analysis indicates significant wear (high metal content, pitting): Proceed to visual inspection of gears and bearings.
   2. Diagnosis of gears:
      1. Visual inspection through inspection hatches/endoscope: Inspect gears for visible defects:
         • Pitting: Microcracks and pitting of metal on tooth surfaces.
         • Wear: Decrease in tooth thickness, traces of fretting.
         • Chipped teeth/cracks: Signs of material overload or fatigue.
         • Burns: Traces of dry friction or lack of lubrication.
      2. Backlash measurement:
         1. Lock one wheel. With the help of an indicator, measure the free movement of the other wheel on the top of the tooth.
         2. Compare the measured backlash with the manufacturer's recommendations (for example, 0.15-0.30 mm). Excessive backlash can cause knocking and vibration.
      3. Checking the contact spot: Apply the marking paste to the teeth and check the gear by hand. Estimate the distribution of the contact spot. An uneven spot indicates inconsistency or inaccuracy of installation.
      4. IF significant defects or excessive backlash found: Specify as cause.
   3. Bearing diagnostics:
      1. Visual inspection: Remove the bearing caps (if possible) and inspect the outer surfaces of the bearings for signs of overheating (discoloration), grease leaks.
      2. Inspection of internals (through endoscope or after disassembly): Look for:
         • Pitting/pitting: On raceways or rolling bodies.
         • Corrosion: Traces of rust due to the presence of water in the lubricant.
         • Separator wear: Separator deformation or cracks.
         • Discoloration: Dark spots indicating overheating.
      3. Manual check:
         1. Check the shaft manually. Is unevenness, biting, grinding felt?
         2. Check the axial and radial clearance with the indicator. Compare with manufacturer's allowable values.
      4. IF Defects or excessive backlash detected: Specify as the cause.
   4. Diagnostics of misalignment, imbalance, weakening:
      1. Continuity check:
         1. Disconnect the clutch. Use a laser alignment gauge (such as the Easy-Laser XT770) to check the alignment of the input shaft of the gearbox with the motor and the output shaft with the working mechanism.
         2. Record the radial and angular displacement values.
         3. Tolerance: Normally radial displacement <0.05mm, angular displacement <0.01mm/100mm.
         4. IF misalignment exceeds tolerances: Adjust equipment position.
      2. Unbalance check:
         1. This requires dynamic balancing, which can be done by a contractor or specialized equipment.
         2. IF vibration analysis indicated significant peaks at 1x rpm: Possible motor rotor or coupling imbalance.
      3. Checking for loosening of fasteners:
         1. Check with a torque wrench all the fasteners of the gearbox to the foundation, engine mounting, bearing caps.
         2. Compare the tightening torques with the manufacturer's specifications.
         3. IF loose fasteners are detected: Tighten them to the desired torque.

   6. Matrix "Fault - Cause"

   This table will help you quickly match observed symptoms with the most likely causes and methods of diagnosis.

   Symptom	Probable causes (by probability)	Diagnostic test	Expected result when confirming the cause
   Gear mesh noise	Gear wear/pitting Incorrect backlash Inconsistency of gears Insufficient or degraded lubricant Gearbox overload	Analysis of the vibration frequency spectrum (GMF and sidebands) Visual inspection of gears (endoscope) Backlash measurement Lubricant analysis	High peaks on GMF and its harmonics Visible defects (pitting, wear) on the teeth Backlash outside the permissible values (>0.3 mm or <0.1 mm) High content of metal particles (Fe, Cr) in the lubricant
   Knocking, Clicking (Knocking, Clicking)	Excessive gear/bearing backlash Loosening of gearbox/foundation fasteners Damage to clutch elements A crack in the gear wheel	Measurement of backlash of bearings/gears Dynamometric control of fastenings Visual inspection of the clutch Impact analysis on the vibration spectrum	Excessive backlash (radial/axial >0.15 mm) Loose fastening bolts Damaged rubber/plastic elements of the clutch High peaks of impact vibrations
   Whining, Squealing	Initial wear of rolling bearings Insufficient lubrication in the bearings Gearbox overload Improper tightening of bearings	Thermal imaging control of bearing assemblies Analysis of the vibration frequency spectrum (high-frequency components, bearing frequencies) Acoustic diagnostics with a stethoscope	Local overheating of bearings (>80°C) Increasing the frequency of bearings on the spectrum A high-pitched, shrill sound from the bearing assembly
   Buzzing, steady noise	Misalignment of shafts Imbalance of rotating parts (engine, clutch) Electrical malfunctions of the engine	Laser alignment check Analysis of the frequency spectrum of vibration (peaks at 1x, 2x rpm) Electrical diagnosis of the engine (if suspected)	Significant radial/angular displacement of the shafts High peaks at the rotation frequency and its harmonics Characteristic electrical frequencies in the vibration spectrum
   Overall increased vibration	Reducer-motor/reducer-load mismatch Weakening of the attachment of the gearbox to the foundation Imbalance (if the gearbox has elements rotating at high speed) Wear of bearings or gears (in advanced stage)	Laser alignment check Dynamometric control of fastenings Analysis of the frequency spectrum of vibration Visual inspection for loose connections	Inconsistency exceeding tolerances Loose anchor bolts Increasing the general level of vibration with a wide range of frequencies
   Vibration with high temperature	Insufficiency or degradation of lubricant Gearbox overload Bearing wear Improper gear engagement	Thermal vision control/Pyrometry Lubricant analysis Overview of internal components	Localized hot spots (>90°C) Decrease in viscosity, high acidity index of the lubricant Visible wear defects on bearings/gears

   7. Analysis of the root causes of malfunctions

   Understanding why malfunctions occur is key to effective troubleshooting and prevention.

   7.1. Gear wear (pitting, abrasive wear, fretting)

   • Why it occurs:
     1. Pitting: Fatigue of the metal surface due to repeated loads. Microcracks form under the surface, then expand, leading to the breaking off of pieces of metal. Accelerates under high loads, insufficient surface hardness and poor lubricant quality.
     2. Abrasive wear: Penetration of solid particles (dirt, dust, wear products) into the lubricant. These particles get stuck between the teeth, causing scratches and wear on the working surfaces.
     3. Fretting: Destruction of the surface that occurs with small relative oscillations of parts under load. Often associated with insufficient backlash, vibration or poor lubrication.
   • How to confirm: Visual inspection of gears through an endoscope or after disassembly. Analysis of the lubricant for the content of metal particles and ferrography to determine the type of wear particles. Vibration analysis will show peaks at the GMF and their harmonics, often with sidebands.
   • Potential damage if not addressed: Progressive wear will change the geometry of the teeth, increase backlash, increase noise and vibration, which can eventually lead to tooth chipping and catastrophic gear failure.

   7.2. Misalignment of the shafts

   • Why it occurs:
     1. Inaccurate installation of the gearbox and motor/load.
     2. Deformation of the base or foundation over time.
     3. Voltages in pipelines or connected mechanisms.
     4. Thermal expansion of components during operation.
   • How to confirm: Laser measurement of the alignment between the shafts of the motor and the gearbox, as well as the gearbox and the working machine. Vibration analysis will show dominant peaks at 1x and 2x shaft speed in the radial and axial directions.
   • Potential damage if not addressed: Excessive stress on bearings and seals, resulting in accelerated wear, overheating and premature failure. It can also cause increased clutch wear.

   7.3. Bearing wear or damage

   • Why it occurs:
     1. Insufficient or contaminated lubricant: Wrong type of lubricant, insufficient level, excessive oxidation or particulate/water contamination.
     2. Overload: Operation of the bearing beyond its designed load capacity.
     3. Incorrect installation: Damage during installation (shocks, incorrect heating), incorrect tightening.
     4. Inconsistency: Additional burdens due to inconsistency.
     5. Corrosion: Due to moisture penetration.
   • How to confirm: Vibration analysis (bearing characteristic frequencies: BPFI, BPFO, BSF, FTF), thermal inspection (local overheating), lubricant analysis (metal content, ferrography), manual bearing clearance check. Visual inspection after disassembly.
   • Potential damage if not addressed: Progressive wear of the raceways and raceways will lead to increased backlash, overheating, increased vibration, and eventually seizing or bearing failure, which can cause significant damage to the shaft and gears.

   7.4. Insufficient or degraded lubricant

   • Why it occurs:
     1. Incorrect replacement interval: The oil is not replaced in time, which leads to its oxidation and loss of properties.
     2. Wrong type of lubricant: Use of lubricant with incorrect viscosity or additives.
     3. Contamination: Ingress of water, dust, wear products through damaged seals or ventilation.
     4. Insufficient lubrication level: Leaks or insufficient filling.
   • How to confirm: Lubricant analysis (viscosity, TAN, water content, ferrography). Visual inspection of the level and color of the lubricant. Thermal imaging control (increase in temperature due to increased friction).
   • Potential damage if not addressed: Loss of protective properties of the lubricant leads to accelerated wear of gears, bearings, seals due to increased friction, overheating and corrosion. This is one of the most common causes of gearbox failures.

   7.5. Loosening of fastenings

   • Why it occurs:
     1. Incorrect tightening torque during installation.
     2. Vibration during operation, which leads to self-unscrewing.
     3. Thermal cycles.
     4. Foundation deformation.
   • How to confirm: Visual inspection and dynamometric control of all fastening bolts of the gearbox to the base, bearing caps. Vibration analysis may show increased amplitudes at 1x, 2x, 3x rpm.
   • Potential damage if not addressed: Increased vibration of the entire unit, additional stresses on components, which can lead to the destruction of the foundation, gearbox housing, failure of couplings and accelerated wear of internal components.

   8. Step-by-step troubleshooting procedures

   The following procedures are general. Always refer to the equipment manufacturer's manuals for specific values ​​and steps.

   8.1. Troubleshooting problems related to gears

   1. Safety: Stop equipment, perform LOTO (Lockout/Tag) according to DSTU EN 1037.
   2. Draining the grease: Drain the old grease into a clean container for disposal or further analysis.
   3. Access: Remove covers or sections of the gear housing to provide access to the gears. Use lifting gear if necessary.
   4. Detailed Inspection: Carefully inspect all gears for pitting, chips, cracks, excessive wear, burrs. Document all damage.
   5. Backlash measurement:
      1. Set a clock-type indicator perpendicular to the top of the tooth.
      2. Lock one wheel. Carefully rotate the adjacent wheel back and forth, registering maximum free travel.
      3. Compare with the permissible values ​​of the manufacturer (typically 0.15-0.30 mm).
   6. Repair/Replacement:
      1. Minor pitting/wear: Grinding or polishing possible (depends on gear type and capability). Consult the manufacturer.
      2. Significant pitting/chips/cracks: Damaged gears MUST be replaced. Order genuine UNITEC spare parts Category "Z" through https://www.unitecd.com/e-catalog/.
   7. Backlash Adjustment: When replacing or after a major repair, establish the correct backlash by using adjustment washers or moving the bearing assemblies according to the manufacturer's instructions.
   8. Cleaning: Thoroughly clean the internal cavities of the gearbox from metal particles and dirt.
   9. Assembly: Assemble the gearbox following the tightening torques (eg 80-120 Nm for the cover bolts) and the sequence specified in the manufacturer's manual.
   10. Topping up with grease: Top up with fresh, manufacturer-recommended grease (ISO VG 220-460 for most industrial gearboxes) to the correct level.
   11. Verification: Run the gearbox without load, then gradually under load. Carry out vibration analysis, thermal imaging and listening with a stethoscope. Make sure there are no abnormal noises and vibrations.

   8.2. Troubleshooting problems related to bearings

   1. Safety: Stop equipment, perform LOTO.
   2. Draining the grease: Drain the grease.
   3. Access and disassembly:
      1. Disconnect the couplings and all connected components.
      2. Remove the bearing caps, seals.
      3. Use special pullers (eg SKF TMMD 100) to safely remove bearings from shafts or housings. Avoid impacts that could damage the shaft or new bearings.
   4. Detailed Inspection: Carefully inspect the disassembly bearings for pitting, wear, corrosion, discoloration. Inspect the seats on the shafts and in the housings for deformations, cracks, and slip marks.
   5. Replacement:
      1. Always replace bearings in a PAIR (if they work in pairs) or all bearings on one shaft.
      2. Use original UNITEC Category "B" bearings.
      3. Assembly:
         1. Clean and lightly grease the seats.
         2. Use an induction heater (eg SKF TIH 100M) to heat the bearing to 80-110°C (never exceed 120°C!) to facilitate installation on the shaft.
         3. For installation in the case, use a press or appropriate installation tools. Make sure that the force is applied only to the end of the ring that has tension.
         4. Check for distortion.
   6. Installing seals: Replace all shaft and cover seals.
   7. Assembly and tightening: Assemble the bearing assemblies, observing the tightening torques of the cap bolts (eg 50-70 Nm).
   8. Filling with grease: Fill in fresh grease.
   9. Verification: Carry out the verifications as specified in Clause 8.1, Clause 11.

   8.3. Correction of ignorance

   1. Safety: Stop equipment, perform LOTO.
   2. Uncoupling: Uncoupling all couplings.
   3. Preliminary check:
      1. Check the cleanliness of the landing surfaces of the motor and gear legs.
      2. Make sure there are no "soft legs" (unstable attachment of one of the legs to the base). Measure the gaps under the legs with feelers. If the gap is >0.05 mm, add calibration shims.
   4. Laser measurement:
      1. Install the laser alignment system (eg Easy-Laser XT770) according to the manufacturer's instructions.
      2. Measure the initial misalignment (vertical and horizontal).
   5. Adjustment:
      1. Vertical Adjustment: Add or remove shims under the legs of the moving unit (usually the engine) to achieve the desired height.
      2. Horizontal adjustment: Move the mobile unit left/right on its base.
   6. Check and remeasure: After each adjustment, tighten the mounting bolts (eg 100 Nm) and re-measure the misalignment until it falls within the tolerances (radial misalignment <0.05mm, angular misalignment <0.01mm/100mm).
   7. Assembly of Couplings: Connect the couplings, making sure that their components are in good condition.
   8. Verification: Perform a vibration analysis. A decrease in the amplitudes at 1x and 2x the rotation frequency will confirm a successful adjustment.

   9. Precautions

   Regular and proactive maintenance is the best way to prevent unexpected failures and extend the life of gearboxes.

   The root cause	Prevention strategy	Monitoring method	Recommended interval
   Gear wear	Using high-quality lubricant of appropriate viscosity (ISO VG). Regular analysis of lubricant. Prevention of gear overload. Correct installation and backlash adjustment.	Lubricant analysis (ferrography, metal content) Vibration monitoring (GMF spectral analysis) Visual inspection through inspection hatches (endoscope)	Lubrication analysis: Annually or every 2000 hours (depending on conditions) Vibration monitoring: Quarterly or every 1000 hours Visual inspection: Every 2-3 years during major repairs
   Misalignment of shafts	Precise laser alignment during installation and after repair. Regular inspection of the foundation and fasteners. Elimination of "soft paws".	Vibration monitoring (peaks at 1x, 2x rpm in axial/radial directions) Planned alignment check (laser alignment)	Vibration monitoring: Quarterly Alignment Check: Every 3-5 years or after any foundation/bracket repair
   Bearing wear or damage	Using quality bearings (eg FAG, SKF, TIMKEN) Correct installation (without shocks, using heating) Optimal lubrication and lubrication intervals. Prevention of grease contamination (quality seals).	Vibration monitoring (characteristic frequencies of bearings) Thermal imaging control Lubricant analysis (metal content) Acoustic diagnosis	Vibration monitoring: Quarterly Thermal imaging control: Monthly or quarterly Lubricant analysis: Annually
   Insufficiency or degradation of lubricant	Observance of oil change intervals in accordance with the manufacturer's recommendations (ISO 4405, ISO 4406). Use of grease with appropriate viscosity and additives. Regular monitoring of the oil level. Ensuring the integrity of seals.	Lubricant analysis (viscosity, water content, TAN, ferrography) Visual control of the level and condition of the lubricant Thermal imaging control	Lubrication analysis: Annually or every 2000 hours Visual control: Weekly/monthly Lubricant replacement: Every 1-3 years (depending on the type of lubricant and operating conditions)
   Loose fastenings	Using proper tightening torques during installation. Use of locknuts or thread retainers (if provided). Regular check of bolt tightening.	Visual review Dynamometric control Vibration monitoring (changes in overall level, peaks at 1x, 2x rpm)	Visual inspection: Monthly Dynamometric control: Annually or during scheduled maintenance

   10. Spare parts and components

   It is important to have access to quality spare parts for quick and efficient troubleshooting. UNITEC-D GmbH is a reliable supplier of original and analog components for industrial gearboxes.

   Description of the part	Specification/Example	When to replace	Category UNITEC
   Rolling bearings (ball/roller)	SKF 22222 EK, FAG 23130 CC/W33	When wear, pitting, noise, overheating are detected, after reaching the estimated service life (L10)	Category "B" (Bearings)
   Gear wheels	Material 18KHGT, hardness 58-62 HRC	With significant pitting, chips, cracks, excessive wear of teeth	Category "Z" (Gears)
   Shafts (input/output)	Steel 40X, accuracy H7	In case of cracks, bends, excessive wear of seats under bearings/seals	Category "V" (Shafts)
   Sealing of shafts (cuffs)	NBR, FKM (Viton) for high temperatures	When detecting lubricant leaks, hardening, cracks, wear	Category "U" (Seals)
   Couplings and their elements	Rubber bushings, disks, toothed rings	When cracked, deformed, excessively worn or damaged	Category "M" (Couplings)
   Lubricant for gearboxes	ISO VG 220, 320, 460 (eg Mobilgear 600 XP)	According to the replacement schedule or according to the results of the analysis of the lubricant	Category "L" (Lubricants)
   Oil filters	The degree of filtration is 10-25 microns	According to the replacement schedule or in case of increased contamination	Category "F" (Filters)

   To order quality spare parts that meet the highest standards, please refer to the UNITEC-D e-catalog at: https://www.unitecd.com/e-catalog/. We guarantee compliance with European quality standards and prompt delivery.

   11. Links

   • DSTU ISO 10816-3:2006 (ISO 10816-3:1998, IDT) Mechanical vibration. Evaluation of machine vibration based on the results of measurements on non-rotating parts. Part 3. Industrial machines with a rated power exceeding 15 kW and rated speeds from 120 rpm to 15000 rpm during in situ measurements.
   • DSTU EN 1037:2003 (EN 1037:1995, IDT) Machine safety. Prevention of unexpected start.
   • DSTU ISO 4405:2005 (ISO 4405:1991, IDT) Volumetric hydraulic drives and pneumatic drives. liquids Determining the degree of contamination by weight.
   • ISO 4406:2017 Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles.
   • Manuals for operation and maintenance of equipment manufacturers (OEM Manuals).
   • UNITEC's internal guidelines for maintenance and repair of industrial equipment.