All motors have a metal nameplate fixed to their body (right).

The nameplate gives a number of the motors characteristics including:

• Brand
  
• kW or hp (horse power)
  
• Hz (frequency)
  
• Amps
  
• Ambient temperature
  
• Efficiency (%)
  
• Voltage (Star / Delta)
  
• RPM
  
• cos φ (power factor)

Manufacturers also publish Motor Efficiency tables (below) and carefully label each of their motors with data that enables the purchaser to match a motor to its end use and enable the selection of a high efficiency motor.