Priority should always be given to proper storage of your spare electric motors. Ideally, you will employ a warehouse management system that excels at maintenance and upkeep of electric motors to ensure reliability. Whether sitting on a shelf or palletized, stored equipment is invested capital. Protecting these assets is a measure of good stewardship which ensures their continued use and protects your company's bottom line. Consider the following tips to make the most of inactive motors while in storage.
Storing Motors for the Short Term
If the motor will be out of service for less than 30 days, then store in a climate controlled environment, preferably 10 to 20 degrees F above room temperature, this will provide winding temperature protection. You may have to achieve these temperatures with space heaters or heating one phase of the winding by "trickle heating" with a low voltage. Additionally, for locations with humidity levels greater than 60 percent, like Florida, rotate the shaft 10-15 revolutions weekly.
Additionally, you will need to employ some form of humidity control method or desiccants. Some motors may require adding oil to the bearing before rotating. Check with your manufacturer for other considerations on motors with hydrodynamic bearings.
Storing Motors for the Mid Term
For storage less than 12 months, there are some added steps that should be taken. Follow the procedure for out of service inspection for less than a month, but conduct a more thorough monthly inspection, plus measure and record the stator winding insulation resistance. If the motor has been subjected to extreme moisture conditions, a megger or insulation resistance meter may need to be used.
Storing Motors for the Long Term
There are instances where you may need to store your motor beyond 12 months. Follow the above procedures, but it is recommended that bearings be re-lubricated and oil changed yearly to prevent damage from contamination gases present in the storage area. Whatever length of time your motor will be in storage, consult storage procedures for your particular brand of electric motor. It may not be practical to apply the same procedures to smaller electric motors as a large electric motor.
Not So Ideal Storage
Climate controlled warehouses are the best option for protecting electric motors. However, that may not be an option for you and the motor will need to be palletized outside in the elements. Cover entire motor with a loose tarpaulin, no need to make it too tight. This will help with air circulation while minimizing condensation. And do your best to protect against pest intrusion.
Avoiding Nearby Sources of Vibration
Some storage locations will be located near ambient vibration areas like construction equipment, rail lines, or production areas. Ambient vibration, although minimal, over time can cause internal bearings to vibrate. Without proper attention to rotating the shaft, wear will be centralized to individual locations on the bearing components. To mitigate against wear, you might consider storing the motors on pallets, old conveyor belts or used rubber boarding to absorb vibrations.
Protecting Stored Motors From Pests
Rodents, birds, and insects can and will enter the motor, cause damage to the insulation winding, block ventilation and drain openings. During storage, insects, rodents, and birds will enter the motor, damaging sensitive areas like the winding insulation. They may also create nests, deposit feces, or die, blocking drain openings or ventilation. Where possible, take precautions to minimize the impact of pests and the negative effects they can have on your stored electric motors.
In addition to standard pest control programs, you might find the following tricks a low-cost remedy:
- Store electric motors in original containers, if possible.
- Place steel wool in drain holes or openings.
- Scented dryer sheets have been proven to repel rodents of all sizes. Try tucking them in the crevices of the motor or place in the container.
- Place mothballs or mothball crystals around the perimeter of the storage area.
- Pinesol liquid cleaner is a great deterrent for raccoons.
Storing your electric motors properly is an important part of protecting your company's assets, ensuring they will be ready for use when you need them. These are just a few general tips to get you started. However, for more specific information, you may contact the vendor of your specific brand of electric motor.