Gear Efficiency Comparison Table

 Spur Gear Efficiency

Spur gearing is a parallel shaft arrangement, and these gears can achieve much higher efficiencies compared to other gears types. Its efficiency varies from 94% to 98% with lower gears ratios.

Straight Bevel Gear Efficiency

Straight bevel gearing is similar to spur gearing with perpendicular shaft arrangement. Like spur gearing these gears also only can handle lower gears ratios with higher efficiencies (93% to 97%).

Spiral Bevel Gear Efficiency

Because of tooth shape and contact spiral bevel having less noise and vibrations compared to straight bevel gears, and thus having better efficiency (95% to 99%).

Worm Gear Efficiency

Worm gears efficiency varies significantly when lead angle, friction factor and gears ratio changes. In higher ratios efficiency of worm gears, drops.

Hypoid Gear Efficiency

Hypoid-Gear

The efficiency of a hypoid gears is around 80-95% and can achieve very high gears ratios up to 200:1.

Helical Gear Efficiency

Helical gears can run with very high pitch line velocity and can achieve much higher efficiencies (94%-98%) with maximum gears ratios up to 10:1.

Cycloid Gear Efficiency

These gears can work in very high efficiencies at relatively high gears ratios above 30:1 and under normal working conditions cycloid gearing efficiency ranges from 75% to 85%.

The post Know Which gear is more efficient? appeared first on MaxPowerGears.

Repairing or replacing a failed gearbox is an extremely expensive undertaking. When a Common Gearbox Failures occurs, it is important to correctly identify the failure mode so that the appropriate actions can be taken to reduce the likelihood of a reoccurrence of the same type of Common Gearbox Failures.

Gearbox failures can be caused by fundamental design issues, manufacturing defects, deficiencies in the lubricant or lubrication system, excessive time at standstill, high loading, and many other reasons. A correct failure mode diagnosis is the first step in identifying the actions that can be taken to prevent additional failures. Five of the most common gear and bearing failure modes, along with tips on identification and potential means of prevention, are provided below.

Micropitting on Gear Teeth

Micropitting can affect both gears and bearings, and failures due to micropitting are very common in gearboxes. Micropitting occurs when the lubricant film between contacting surfaces is not thick enough and the surfaces have high amounts of sliding action. Micropitting results in a frosted or matte finish surface in affected areas, as seen in the figure above. Micropitting-related failures can be prevented by changing lubricant type or by reducing component surface roughness.

Macropitting on Gear Teeth

Macropitting can also affect both gears and bearings. Macropitting occurs when the contact stress in the gear or bearing exceeds the fatigue strength of the material. Gears and bearings are typically designed for a 20-year service life, and macropitting that occurs before the end of the design life is an indication that one or more design assumptions, such as contact stress, material properties, lubricant condition or applied load, were not met. Macropitting results in craters on the gear tooth or bearing ring (or roller) surface. Beach marks due to the presence of corrosion and lubricant in the crack are sometimes present and indicate a fatigue progression process. Macropitting failures can be prevented by reducing loads, improving gear and bearing profiles to reduce stress, using cleaner steel, or increasing material strength, through alloy selection or a heat treatment process.

Bending Fatigue

Bending fatigue is a failure mode that affects gear teeth. Bending fatigue failures occur when the stress at the root of the gear tooth exceeds the capability of the gear material. This can be due to excessive loads, incorrect heat treatment, inclusions in the steel or a notch in the root of the tooth. The appearance of the fracture surface will vary depending on whether the failure was high or low cycle fatigue. Features such as ratchet marks are occasionally present and indicate multiple crack origins. Bending fatigue failures can be prevented by decreasing load, increasing gear material strength or optimizing the gear root fillet geometry.

Fretting Corrosion

Fretting corrosion can affect gears and bearings. It is a surface-wear phenomenon that occurs when two contacting surfaces have small oscillating relative motions, with no lubricant film between the surfaces. It often occurs in gearboxes due to transportation or to spending extended periods of time with no rotation. Fretting corrosion can be identified by the presence of ruts along the lines of contact, along with the presence of reddish-brown or black wear debris. Fretting corrosion can be prevented by minimizing the amount of time that a gearbox spends without rotating or by improving transportation conditions, depending on the cause of the fretting corrosion

Axial Crack

Axial cracking is a phenomenon that occurs in bearings, almost always on the bearing inner ring. Common Gearbox Failures of this type have become very common in gearboxes and were the subject of an article in the June 2013 issue of North American Windpower. The cracks develop in the axial direction, perpendicular to the direction of rolling. Axial crack failures are most likely to occur in through-hardened bearings. Axial crack failures can be prevented by using case carburized bearings, ensuring that the appropriate amount of retained austenite is present, applying a black oxide coating, and ensuring the correct level of interference fit exists between the bearing inner ring and the shaft on which it is mounted.

The post Five Common Gearbox Failures And How To Identify Them appeared first on MaxPowerGears.

1. Check the Ratings

First off, check if your gearbox is working according to its manufacturer’s specifications for mechanical and thermal ratings.

Gearboxes are often operated beyond their specifications which leads to early malfunction.

2. Regular Lubrication

A well-maintained gearbox is the one that is properly lubricated on a regular basis.

However, make sure to use the recommended type and grade of lubricant in the right proportion.

3. Oil Leakage

Maintain regular inspection for oil leaks at the input and output shaft of your industrial gearbox.

Oil leakage indicates a shaft seal malfunction, which allows dust, debris and water to enter the gearbox.

4. Temperatures

Check your gearbox for signs of overheating, such as burnt exterior paint or oil getting darker in the sight glass.

5. Vibration Test

Mostly industrial gearboxes operate in a noisy environment, which makes it difficult to record each and every variation and increases in the noise.

Conduct regular vibration tests of the internal bearings and gears, to notice any prominent change in the internal condition of the gearbox

6. Clean Workplace

Gearboxes are often operated in a dusty environment, which can result in increased temperature or adulteration of the gearbox.

This Might not be a noticeable problem at first, but it’s important to minimize for long-term maintenance.

The post A guide to industrial Gearbox Maintenance appeared first on MaxPowerGears.

The chance of electric shocks, fires, or explosions can be reduced by giving proper consideration to the use of grounding, thermal and over current protection, type of enclosure, and good maintenance procedures. The following information supplements the foregoing safety considerations: This information is not purported to be all-inclusive and the aforementioned references should be consulted.

1. Do not insert objects into the ventilation openings of products.
2. Sparking of starting switches in AC motors so equipped, and of brushes in commutator type motors, can be expected during normal operation. In addition, open-type enclosures may eject flame in the event of an insulation failure. Therefore, avoid, protect from, or prevent the presence of flammable or combustible materials in the area of motors/gearmotors.
3. Max power gears totally enclosed products are not explosion proof or dust ignition proof nor does Max power gears offer such products for hazardous locations (flammable/explosive gas, vapor, dust). When dealing with hazardous locations, an approved explosive proof or dust ignition proof product is the recommended approach. Exceptions are allowed by the National Electrical Code: The NEC and the NEMA safety standard should be studied thoroughly before exercising this option.
4. Open, ventilated motors are suitable for clean, dry locations where cooling air is not restricted, Enclosed motors/gearmotors are suitable for dirty, damp locations. For outdoor use, wash downs, etc., enclosed motors must be protected by a cover while still allowing adequate air flow.
5. Moisture will increase the electrical shock hazard of electrical insulation. Therefore, consideration should be given to the avoidance of (or protection from) liquids in the area of motors. Use of totally enclosed motors/gearmotors will reduce the hazard if all openings are sealed.
6. Products equipped with thermal protectors are labeled “THERMALLY PROTECTED.” If severe over-loading, jamming, or other abnormal operating conditions occur, such heat sensitive protectors operate to open the electric power supply circuit. Motors/gearmotors with “automatic” thermal protectors MUST NOT be used where automatic restarting of the drive unit could be hazardous in that clothing or parts of the human body could be in electrical or physical contact with a machine that starts unexpectedly when the thermal protector cools down. MANUAL RESET protectors or suitable electric supply disconnect devices/procedures should be used where such hazards could be created.
7. The windings of DC stepper motors, or their switching transistors, must be disconnected from the DC power source to avoid unexpected motion. If not, extraneous signals could turn on the power transistors and generate motion.
8. Some oil-type capacitors contain a nonPCB impregnate which is flammable. Such capacitors are identified by means of a Warning Label and, in addition, are stamped “NON-PCB.” The user has to provide at least .57 in. (14.5 mm) clearance beyond the terminal blades for case expansion to allow an internal safety switch to permanently open and electrically disconnect the capacitor. The internal pressure sensitive switch is designed to prevent the expulsion of the flammable dielectric medium if excessive temperatures are generated by electrical operation. Do not discard such capacitors into open fire as excessive internal heat could cause them to explode.
9. Motors/gearmotors which employ capacitors can develop more than nameplate voltage across the capacitor and/or capacitor winding (depending on design). Also, overdrive voltages may be many times greater than a stepper motor’s continuous voltage rating. Suitable precautions should be taken when applying such motors.
10. Abnormal conditions, such as cut-out switch failure, or a partial winding failure, can very occasionally cause some AC motors/gearmotors to start in a direction reverse from normal. Also, use of a capacitance or resistance value other than that recommended for Hy-Sync motors may result in unpredictable reverse operation. Susceptibility to unplanned reversing under such conditions is greatest when the motor’s actual load is light relative to its rated load. One-way clutches or similar devices are advisable if unexpected reverse rotation is unsafe in the application.
11. Do not rely upon self-locking gears or permanent magnet, stepper, Hy-Sync, or energized motors to hold a load in place if movement could result in personal injury. Mechanical locking devices should be used in such applications.
12. For motors driven by electronic controls, do not use a function of the control for safety interlock purposes. An independent switch or relay should be used. On stepper motors, the device should be between the control and the motor.

The post 12 Safety Considerations you must know about Gear Motors appeared first on MaxPowerGears.