Farm Power And Machinery (1+1)

Care and maintenance of Electric Motors

Care

• Keep the motor bearings properly lubricated.
• Keep the motor clean and well ventilated.
• Never overload the motor and thus avoid damage to the motor due to burning of the windings.
• Keep the belt moderately tight between motor and driven machine.
• Never connect the motor to too low or high supply voltage. Both conditions are harmful.
• Keep the motor grounded.
• Keep the motor away from moisture, dust and saw dust.
How to Clean a Motor
Electric motors must be kept clean and lubricated if they are expected to work efficiently for a longer period.
The following procedure should be observed to keep a motor clean :
• After having disconnected the motor from the power, it is necessary to disassemble it by removing the rotor, shaft and fan assembly. All possible care should be taken not the break any wire connection or centrifugal switch mounted on the rotor shaft or elsewhere.
• The second step is to blow out the loose dirt from the motor windings and from inside the end plates by using pressurized air from a blower or from a cycle pump. If necessary, a dry paint brush or cloth can be used to carefully wipe off dirt that might remain even after using pressurized air.
• All dirt from the air passages in the frame and in the rotor should be removed. Metal parts may be washed with non- inflammable fluid.
• All the accessories like the starting switch, the commutator and brushes should be checked and repaired before the parts are reassembled.
• Lastly the motor bearings are lubricated with the recommended type of lubricant before the connection is provided to check its operation.

Fuse: Fuse generally means a fuse wire, placed in a fuse holder. It is a safety device, which protects electrical/electronic circuits against over loads, short circuits and earth faults. The fuse is connected in the phase of the supply. When the current taken by the circuit exceeds the rated current of the fuse wire, the fuse wire melts and cuts. This disconnects the supply from the circuit and thus protects the circuit and the components connected in the circuit. Rating of the fuse: The maximum current that a fuse can carry, without being burnt, is called the rating of the fuse wire. It is expressed in Amperes.
Example: 5 A fuse, 10 A fuse, 16A fuse, 60A fuse, 100 A fuse, etc. Current rating of the fuse, selected for a circuit, should be equal to the maximum current rating of the machinery, appliance or component connected in the circuit.