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Routine maintenance for electrical equipment
Electrical periodic maintenance should be done for electrical motors, generators, lighting systems, control circuits and switchgear.
A preventive maintenance check list may include cleaning, oil changes, lubrication, repairs, inspecting adjustments, and replacing parts of the equipment, this is regularly scheduled based on time and equipment. Let’s have a look at preventive maintenance for some electrical assets.
Preventive maintenance for electrical generator
Electrical generators have two parts, mechanical and electrical. The mechanical part is the engine. I made maintenance for electrical part only. The mechanical team take care of the engine. So, let’s discuss the preventive maintenance of the generator electrical parts.
Weekly bases generator maintenance:
- Measure generator output voltage and current using a multi-meter and compare it to the readings of the generator meter.
- Check battery charger output current and voltage.
- Check battery voltage.
- Check the generator control circuit for any loosen connections or terminal corrosion. Finding any corrosion early prevent faults and shutdown.
- If the generator is outdoors, check its parts sealing. Make sure no dust enters the control panel.
- If the generator is stand by, start it and keep it running for 15 minutes to charge batteries.
- Make sure the generator is connected to a good earthing network.
- Keep the batteries clean.
Yearly bases generator maintenance:
- Check stator resistance by megger tester.
- Check rotor resistance.
- Check vibration and make sure the generator bearing is not damaged.
- Make sure the fan has a secure guard.
- Make sure the generator emergency shut down is working properly.
- Check output voltage, current and frequency and record the data.
- Inspect exciter and armature windings. Make sure no corrosion in the wires.
Electric Motor Preventive Maintenance Tips
For electrical motors some of maintenance are periodically done to keep the motor running in a good condition. Some activities are done while motor is running and others are done with motor stopped.
- Check motor temperature rise using thermal imaging.
- Check Motor voltage and current.
- Check motor vibration using a vibration measuring tool.
- Check motor earthing cable connection.
- Measure earthing resistance and make sure its value is < 5Ohm
- Check motor lubrication. Make sure to follow the motor nameplate lubrication period.
- Make sure to record all data and findings.
For more information about, how to check electric motor, check out the detailed article here.
Control circuits routine maintenance
Electrical control circuits and panels don’t have the same components, as each circuit has its own requirements.
But in general you should keep the panel or the circuit in good condition by performing some basic periodic maintenance, some are listed below
- keep the panel clean and dust free.
- check panel working voltage.
- check the panel for any abnormal noise.
- thermal imaging for the panel components.
- measure current if necessary.
I have written a detailed article about electrical maintenance work, you can find it here.
Lighting systems periodic maintenance
- turn on lights and check any damaged lamps
- check photocell if found
- clean and keep the panel clean
- check control contactors for any abnormal noise
- check voltage of the lighting panel
- thermal image the components for any temperature rise
Electric Transformer Preventive Maintenance Tips
Oil immersed transformers are electrical stationary machines with oil tank and some other accessories, below are some periodic maintenance for them.
- Check transformer temperature rise using thermal imaging. And compare it to the transformer temperature gauge.
- Check transformer voltage and current. IF the transformer is a medium or high voltage transformer, you an get the voltage and current readings from the switchgear.
- Check transformer noise, make sure its as normal. This check step needs an expert labor to do it.
- Check transformer earthing cable connection.
- Measure earthing resistance and make sure its value is < 5Ohm
- Check transformer oil leakage on it body or under its base. If there is any oil spillage, check its source. Make this daily.
- Check silica gel color. Make sure its not saturated by moisture. Make this daily.
- Check oil level in the conservator tank. If the transformer is hermetically sealed, then check oil level gauge.
- Check cooling fans and oil pumps. Make sure it work properly in hot days and stop in cold ones. In many cases we find the cooling fans closed by plastic bags. Which lower its cooling capacity.
- Yearly task is to clean bushing.
- Make sure to record all data and findings.
Read also my other detailed article about transformer most common 7 faults. Also, check out my article, electrical maintenance work. It has more detailed transformer maintenance.
