Keeping your swamp cooler motor from overheating is an important part of the overall maintenance of your evaporative cooling system. Your swamp cooler works using a pump to recycle water through a wetted mat. Your swamp cooler motor turns a belt-driven fan that sucks air through this wetted mat.\\
As the water evaporates, the air being sucked through this mat is much more cool and humid than the air in a hot dry climate. This air is pushed by the fan into the house and cools and humidifies the air. There are several reasons why your swamp cooler motor may overheat and stop this process. When that happens, here are some things to consider.
Step 1 - Remove Side Wall Cover
To access the internal components of your swamp cooler including your swamp cooler motor you must simply remove the screws from the back side panel of the swamp cooler. Once the screws are removed you should easily be able to slide out the back panel and wetted cooling mat to expose interior components.
Step 2 - Check Belt Tension
The sides of your swamp cooler will slide off very easily and doing this will expose the water pump, motor, and belted fan inside. Once inside check the tension of the belt running from the swamp cooler motor to the fan. It should not be too tight or too loose. Incorrect fan belt tension could cause your swamp cooler motor to overheat. Roughly speaking there should be about one inch of play in the tension of your fan belt.
Step 3 - Check Shaft Bearings
Your motor will have two shaft bearings that are sometimes called "squirrel cage" shaft bearings. Each of these shaft bearings should have an oil port attached. Make sure that these shaft bearings have enough oil to spin freely. If these bearings do not have enough oil they can begin to seize and cause the swamp cooler motor to overheat.
Step 4 - Check Electrical Connections
Make certain that the electrical wiring and connections on your swamp cooler motor are secure and not overheating themselves or shorting out. Also, a bad switch in the swamp cooler motor or fuse can cause the motor to get hot and shut off. Make sure that all connections, switches, and wires are correctly installed and maintained to avoid the swamp cooler motor from overheating.
Step 5 - Check Proper Voltage
The motor in your swamp cooler is set to run at or below a specific voltage. If too much voltage is put to the motor, it can overheat. Too much voltage can cause damage to internal wiring and circuitry. Make sure that the proper voltage for the motor is what is being applied to avoid damage and overheating. The voltage capacity for the motor will be printed on the side of the swamp cooler motor. Note that the listed voltage capacity of the motor is not the correct working voltage of the motor. To run properly and not overheat, the motor should run at 55 to 60 percent of the total voltage capacity.