How to judge the quality of gear reducer motor?
Oct 23, 2018

When the gear reducer motor runs or breaks down, it can be prevented and eliminated in time by watching, listening, smelling and touching to ensure the safe operation of the gear reducer motor. Now let's learn more about these judgements.


  (1). when a stator winding is short circuited, it may be seen that the motor is smoking.

  (2). when the motor is seriously overloaded or running out of phase, the speed will slow down and there will be a heavy "buzzing" sound.

  (3). The motor maintenance network runs normally, but when it stops suddenly, sparks will be seen at the loose junction, fuses will be broken or some parts will be stuck.

  (4). If the motor vibrates violently, it may be that the transmission device is stuck or the motor is not fixed properly, the foot bolt is loose and so on.

  (5). If there are discoloration, burning marks and smoke stains at the contacts and joints of the motor, it indicates that there may be local overheating, poor contact at the conductor joints or burnout of the windings.

cycloid gearbox

                                                                                 Cycloid Gearbox


The gear reducer motor should emit a uniform and lighter "buzzing" sound when it is running normally, without any noise or special sound. If the noise is too large, including electromagnetic noise, bearing noise, ventilation noise, mechanical friction noise, etc., may be a fault omen or phenomenon.

  1. For electromagnetic noise, if the gear reducer motor makes a sudden high or low and heavy sound, the reasons may be the following.

  ---(1) The air gap between the stator and the rotor is not uniform, at this time the sound is suddenly high or low and the interval between the high and low sounds is not changed, which is caused by bearing wear so that the stator and the rotor are not concentric.

  ---(2) Unbalanced three-phase current. This is the three-phase winding fault grounding, short circuit or poor contact and other reasons, if the sound is very dull, indicating that the motor is seriously overloaded or phase operation.

  ---(3)Loose core. Gear reducer motor in operation because of vibration and iron core fixed bolt loosening caused by iron core silicon steel sheet loosening, noise.

  2. For bearing noise, it should be monitored frequently during the operation of gear reducer motors. Monitoring method is: one end of the screwdriver against the bearing installation part, the other end close to the ear, you can hear the sound of bearing operation. If the bearing is in normal operation, its sound is continuous and small "sand" sound, there will be no change in height or fall and metal friction sound. If there are the following voices, it is abnormal.

  ---(1) Bearing operation when there is a "squeak" sound, this is the metal friction sound, generally due to the lack of oil bearing, bearing should be removed to add a certain amount of grease.

  ---(2) If there is a "gurgling" sound, which is the sound produced when the ball rotates, generally caused by dry grease or lack of oil, can be injected with appropriate amount of oil.

  ---(3) If the "click" or "crunch" sound occurs, it is the sound of irregular movement of the ball in the bearing, which is caused by the damage of the ball in the bearing or the long-term use of the motor, and the drying of the grease.

  3. If the transmission mechanism and the driven mechanism make continuous rather than high or low sounds, they can be dealt with in the following cases.

  ---(1) Periodic "popping" sound is caused by uneven belt joints.

  ---(2) Periodic "babbling" is caused by loosening of coupling or pulley and shaft and wear of keys or keyways.

  ---(3) Uneven impact noise is caused by fan collision with fan cover.


By hearing the smell of gear deceleration motor running can also identify and prevent failure. Open the junction box and sniff it. See if there is a burnt smell, if there is a special smell of paint, indicating that the internal temperature of the gear reducer motor is too high; if there is a heavy smell of paste or scorched odor, it may be insulating layer maintenance network breakdown or winding burned. If the connection box of the gear reducer motor has no smell, the insulation resistance between the winding and the casing should be measured by megohm meter to be less than 0.5 megohm, so it must be dried. The resistance is zero, indicating that it has been damaged.


The temperature of some parts of the gear reducer can also be used to determine the cause of the failure. In order to ensure safety, the back of the hand should be used to touch the outer shell of the motor and the surrounding parts of the bearing. If abnormal temperature is found, the reasons may be as follows.

  1. Poor ventilation. Such as fan shedding, ventilation duct blockage.

  2. The overload of the gear motor causes the overheated current to cause the stator winding to overheat.

  3. Gear reducer stator winding inter turn short circuit or three-phase current imbalance.

  4. Frequent start or brake.

  5. If the temperature around the bearing is too high, it may be caused by bearing damage or lack of oil.

After understanding the above contents, we can judge the quality of the gear reducer motor by watching, listening, smelling and touching four methods in the use of the schedule. No matter which aspect of the equipment is damaged, it can not run. So once we find the quality problem, we must repair it in time.

*For more detailed parameters,size,price.Pls contact the Hangzhou Starred-River Machinery Co., Ltd.




Facebook:0086 18257963886

Whatsapp:+0086 18257963886

  • facebook