Advantages and disadvantages

 Advantages of universal motor :

• High speed from above 3600 r.p.m. to around 25000 r.p.m.
• High power output in small physical sizes for use in portable tools*
• High torque at low and intermediate speeds to carry a particularly severe load.
• Variable speed by adjustable governor, by line voltage or especially by modern pulse techniques.

Disadvantages :

• Increased service requirement due to use of brushes and commutators. The life of these parts is limited in severe service.
• Relatively high noise level at high speeds.
• Moderate to severe radio and television interference due to brush sparking.
• Requirement for careful balancing to avoid vibration.
• Requirement for reduction gearing in most portable tools.