Significance

• Many motors may have the capability of being wired for multiple voltages. Wiring diagrams on the identification nameplate will indicate if this is possible. A motor that is capable of running at 220 Volts Alternating Current (VAC) but wired as 120 VAC, will draw twice as much amperage. This double amperage will lead to a higher electrical flow every time the motor is started. Motors that run at a lower voltage are also prone to overheating which makes them less efficient.
  
  

Function

• Overheating of motors not only makes them inefficient but it can also create a premature death in the life of the motor. Many times, in dirty or dusty environments, the air fan which cools the motor may become clogged with debris. A cleaning schedule may have to be employed to either blow out or vacuum the air fan on a motor.
  
  

Types

• Improper lubrication or bad bearings cannot only create heat in the motor but may also cause an excessive load condition. The motor is designed, if properly sized, to pull the load it is driving. When the bearings become dry from lack of lubrication, the motor now has to overcome the additional friction. This friction is caused by the metal against metal grind, in the failing or poorly lubricated bearing.
  
  

Features

• Poor alignment through the drive pulley or mechanical coupling can also be a cause for an excessive load. Drive belts should be inspected on a periodic basis as well as all mechanical couplings. If the drive pulley or coupling are in good shape, the device being driven by the electric motor may be damaged and in need of repair. Manufactures offer troubleshooting tips for most devices driven by electric motors. Checking the draw of amperage is one of the tips.
  
  

Identification

• The proper use of a clamp on ammeter can go a long way in diagnosing an excessive draw for an electric motor. All electric motors will have the load amperage on the nameplate. Using the ammeter can either confirm or deny the proper or excessive amperage, by corresponding the meter reading to the nameplate data.
  
  

Effects

• Removing the drive belt or coupling from the driven device can help in identifying the problem. If the motor has little, to no draw amperage when disconnected from the load and running, the problem may lie with the device. If the device is okay, the motor windings may be getting weak and the motor replaced. Motor windings that become weak prematurely, may be an indication that the electric motor is undersized for the load it is driving.