Electric motors are widely used in life, and they are used for many purposes. Some motors are used in common situations and are also useful in special workplaces.
For example, the motor of gas station fuel dispensers are special and must have explosion-proof performance!
Below is a photo of the motor I maintain during work. This motor has an output power of 150KW, a speed of 1180RPM, a voltage of 440V, and a weight of up to 1.16T
Reference Wikipedia ： https://en.wikipedia.org/wiki/Electric_motor
An electric motor is an electrical machine that converts electrical energy into mechanical energy.
Most electric motors operate through the interaction between the motor’s magnetic field and electric current in a wire winding to generate force in the form of rotation of a shaft
Always perform a risk assessment before maintenance!
We all know that the maintenance of different equipment generates different risks.
Some devices are heavy, some have electricity, some are hot, and some may even explode
In addition to the machine itself, there are other unsafe factors that we need to consider, such as:
- Are there flammable materials around the work?
- Is the venue location high?
- Does anyone walk around and so on
- In short, keep in mind that work is never a matter for you alone, and your small actions may hurt yourself or even others.
- Ensure that maintenance personnel have fully understood the machine manual
- Make sure the machine is powered off and completely stopped
- Power of the power supply and seal the switch with tape on the machine control panel
- Make sure workers are wearing protective equipment. (PS: helmet, protective shoes, earplugs, goggles, gloves, etc.)
- Prepare the required tools and professional tools
- Make sure you have enough spare parts
Screwdriver, Heating equipment for bearings, Hammers (standard and soft-faced), Spanners (various sizes), Adjustable spanner, and so on
Removing the motor side cover
a. In order to protect the wire, please cover the connector of the wire with tape
b. Use a wrench to loosen the four through bolts of the motor
c. Loosen the two fixing screws of the front bearing of the motor
d. Remove the front cover of the motor, and use both hands to carefully remove the rotor of the motor (Caution: Do not hurt around the stator of the motor, please call for help if necessary)
Remove the bearings
a. Use special tools and screwdrivers
b. One person fixes the special tool and screwdriver, and the other person rotates clockwise with a wrench
c. When you feel that it is very difficult to use a wrench, please remember not to use too much force, it will hurt the surface of the rotor parts
d. Use a plastic hammer to carefully tap the special tool. You will find that the situation is getting better immediately. Take out the front bearing slowly！
e. Remove the rear bearing of the motor in the same way
Inspection and clean
When the motor is disassembled, do not rush to replace spare parts and install them. If you do that, everything will be meaningless, especially because of the motor trouble.
When some spare parts can still run normally, but you replace them with new ones, it will cause unnecessary waste.
- Inspect the wires outside the motor for damage
- Check whether the motor stator coil group is normal and there is no sign of burning
- Check if the bearings are stuck. Turn the bearing by hand and listen for noise with your ear
- Check the surface of the rotor for wear and whether the shaft is bent
When all inspection work is completed, please use a special electrical cleaner or compressed air to clean
Before installation, there is knowledge to share!
Do you know what the model letter “2Z” stands for?
2Z– Bearing is a sealed type. It does not need to be added for normal maintenance. It does not need to add extra grease
Z– Bearings are semi-sealed. Although the manufacturer has placed grease, usually a manual pump is needed to inject
No “Z”– the bearing is not sealed, this type of bearing we need to place grease, and usually need to use a manual pump to inject
After choosing the right bearings, let’s install it now
a. Use sandpaper to clean the surface of the bearing to ensure that the bearing can be installed properly
b. Use a heater to heat the bearings (PS: make the bearing better installed by the principle of thermal expansion and contraction, pay attention to the safety of the heater)
c. The bearings are placed with the insulated gloves, and the manual rotation method ensures the normal bearing again.
d. Use a hollow tube (PS: make sure that the inner diameter of the tube is exactly equal to the inner diameter of the bearing. When it is larger than the inner diameter of the bearing, it will seriously damage the bearing)
e. Use a plastic hammer to knock the hollow tube to ensure that the bearing is installed in the correct position
Put back the motor side covers
a. Clean the stator parts of the motor with compressed air
b. Use both hands to place the motor rotor
c. Don’t forget to place the spring part of the bearing
d. Place the side plate of the motor and tap lightly with a plastic hammer
e. Use two bolts to ensure that the bearing gland is in the correct position, remove one of the bolts, and install the screws
Same way for the other bolt
f. Place the through bolts of the motor side plate and fix them with a wrench
See, is the above tutorial very simple?
This tutorial will help you save a lot of money and be able to check various problems of the components
Of course here, we still haven’t finished the maintenance work, Let ’s test if the motor is burned out and the grounding condition!
When you need to test the insulation of the motor or the internal windings, you need to prepare a multimeter. Yes, a multimeter is enough
Please turn the multimeter to the ohm position (PS: the position is displayed as “Ω”)
Use both ends of the multimeter to test three sets of wiring. (Sequence: 1-2, 1-3, 2-3)
When the number of the meter is “∞”, it means that the internal coil is disconnected, which is abnormal.
When the number of the meter is “0”, it means that there is a short circuit inside the machine, which may be the cause of water