There are a variety of reasons why geared motor units fail so it is wise to have a good understanding of them all to better diagnose any recurring problems you have with failing gear motors.
The easily avoided reasons for failure are a lack of proper lubricant and inadequate mounting, so make sure you know what oil or grease is required for the specific motor and ensure the mounting is stable and secure. This article highlights the other issues that cause failure, but which are less easy to detect.
One of the most common reasons for failure is a geared motor unit being undersized and thus does not produce enough power for the application. This results in the motor overheating. The overheating can be difficult to notice before failure if you cannot feel the heat, especially if you are not regularly checking the temperature.
Undersized geared motor units have to work harder than they are designed for and thus burn out much faster than an adequately sized motor. Usually these instances result in a permanent and unrecoverable failure and the motor must be replaced.
The undersized and overheating motor will also compromise the lubrication oil. When the temperature of the lubrication oil rises too high, it begins to break down thermally, leading to failure. When this happens, you might be able to smell the oil or see paint discoloration on the application.
Excessive Overhung Loading
The radial load on the shaft can badly damage bearing support systems, a problem known as excessive overhung overload. Overloaded shafts suffer from shaft fatigue which leads to failure and may require a gearbox repair service as provided with a free inspection and report by gearboxes suppliers such as YB Components.
Remember too that high thrust forces on shafts can exceed their bearing capabilities, which then compromises the press fits of the various components. These high thrust forces can exceed the structural housing strengths of the application’s components, leading to failure.
Gear Tooth Fractures
The teeth of a gear can be fractured when gearboxes experience shock loads from large inertia loads. It can also happen when excessive acceleration or deceleration of the loads occurs, fracturing the gear teeth and causing failure of the application.
Excessive torsional loadings have a similar effect, especially when the excessive torsional load occurs at a keyway or cross-hole.
Unprotected Gear Motors
Geared motor units operating in environments that interfere with their operations need to be protected from the effects of the environment. Dirt and extreme temperatures are the main culprits, so make sure any gearboxes operating in these environments are covered correctly.
Unprotected gear motors will show signs of stress on the gearbox sealing package and will often suffer problems with the lubrication oil. Another common issue caused by a lack of protection is poor heat dissipation, so always ensure the gear motors are protected from environmental interference.
Each environment will need to be monitored because another problem that causes failure is excessive condensation, which occurs if the geared motor unit is subjected to thermal cycling. Keeping the gear motor totally enclosed and protected in this situation can cause failure due to the build-up of condensation, so make sure to regularly vent the application and the motors driving it.
Source: YB Components ltd