Preventive maintenance programmes are the key to reliable, long-life operation of electric motors.
Whilst AC Induction Motors are particularly reliable in service, almost all electrical equipment requires periodic planned inspection and maintenance. Planned preventive maintenance ensures electrical motors, and starters are kept in good working condition at all times. This is critical for businesses that rely on electric motors. A scheduled routine of motor inspection should be carried out throughout the motor’s life. Periodic motor inspection helps prevent serious damage to motors by locating potential problems early.
Planned electric motor maintenance programmes are designed to help prevent breakdowns, rather than having to repair motors after a breakdown. In industrial operations, unscheduled stoppage of production or long repair shutdowns is expensive, and in marine shipping environments, a potential safety issue. Periodic inspections of motors are therefore necessary to ensure best operational reliability.
Preventative maintenance programmes require detailed checks to be effective. All motors onsite (factory, ship etc) should be given their own individual identification (ID) number and have a record log. The record log is usually computerised these days. The motor records kept should identify the motor, brand, inspection dates and descriptions of any repairs previously carried out. By record keeping, the cause of any previous breakdowns can help indicate the cause of any future problems that might occur.
All preventative maintenance programmes should refer to the equipment manufacturer’s technical documentation prior to performing equipment checks.
There are simple routine maintenance checks that can be applied to three phase induction motors, which help ensure a long service life to a motor.
The Simple checks that can be carried out, include a review of the service history, noise and vibration inspections. Previous noise issues could for example be due to motor single phasing. Previous vibration may have been due to worn bearings, which allow the Stator to turn. Other checks include visual inspections (damage and burning), windings tests (insulation resistance & continuity), brush and commutator maintenance (dc motors) and bearings and lubrication.
Inspection frequency and the degree of inspection detail may vary depending on such factors as the critical nature of the motor, it’s function and the motor’s operating environment. An inspection schedule, therefore, must be flexible and adapted to the needs of each industrial or marine environment.
A modern approach to electric motor preventative maintenance is to connect the motor to the Internet cloud, or local company server network.
Motor performance parameters such as phase current, rotational speed, heat and vibration, can all be recorded using sensors.
The sensors are attached either directly to the motor, in the case of vibration sensing, or connected to the power supply feed cable.
Wireless technologies such as LoraWAN can be used to connect remote machinery to the Internet of Things Cloud.
This is also known as IOT or IIOT.
(c) Craig Miles 2019. craigmiles.co.uk & yesway Ltd
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