Transfer Switches

Transfer switches are a type of electrical switches that function by transferring electrical power back and forth between two power systems or buses including utility power line and a backup motor-generator power supply. These transfer switches are widely used in applications that require switching between two power sources.

These transfer switches are often used in electrical power distribution systems, as they can switch from a primary power source to a secondary or tertiary power source. Some transfer switches allow switching power from a regular power source to a temporary generator.


Types of Transfer Switches

• Manual transfer switches
• Automatic transfer switches
• Combination transfer switches

Transfer switches may also feature a sensor for monitoring current levels from a utility line. On decrease in the current level, the sensor sends a signal to a backup generator to switch power sources automatically. This helps in stopping the power flow from the utility line and drawing power from the generator.

Buyers Guide for Transfer Switches
Buyers must keep the following points in mind while selecting transfer switches. These include:

• Proper analysis of product specifications: This includes:
  • Current rating
  • Number of poles
  • Voltage rating or VAC
  • Return-to-utility time
  • Dimensions
  • Weight
    
    
• Product certifications and approvals:
  This includes conforming to the established industry standards and regulatory requirements. Certifications and approvals can be obtained from organizations like:
  • National Electrical Manufacturers Association or NEMA
  • Underwriters Laboratories or UL
    
    
• Product applications: Transfer switches are used in diverse fields including:
  • Material Handling
  • Manufacturing
  • Power generation