Changeover switches, also known as transfer switches, are electrical devices used to transfer an electrical load between two sources, typically between a utility power source and a backup generator or between two different power sources. They are essential for ensuring continuous power supply and preventing power interruptions in various applications, including residential, commercial, and industrial settings.
Functions of Changeover Switches:
1. Reliability: Changeover switches ensure a reliable and seamless transition between power sources, minimizing downtime and the risk of data loss or equipment damage.
2. Safety: They provide a safe method for switching between power sources by isolating the sources during the transfer process to prevent backfeeding, which could be hazardous to utility workers or damage equipment.
3. Automatic or Manual Operation: Changeover switches can be manual, where an operator switches the load between sources, or automatic, where the switch is controlled by a transfer panel that detects power loss and automatically switches to the backup source.
4. Load Balancing: In some cases, changeover switches can be used to balance the load between two power sources for efficiency or to prevent overloading of a single source.
Find more information in https://konrak.com/products/rotary-cam-switches/
Wiring Methods for Changeover Switches:
The wiring of changeover switches can vary depending on the type (single-phase or three-phase), the application, and local electrical codes. Here is a general outline of the wiring process:
1. Power Sources Connection:
– Connect the incoming power source (e.g., utility power) to one of the switch’s input terminals, typically labeled ‘L1’ for line 1.
– Connect the alternate power source (e.g., generator) to the other input terminal, usually labeled ‘L2’.
2. Load Connection:
– The load is connected to the switch’s common output terminal, often labeled ‘C’ or ‘Load’.
3. Neutral Connection:
– If applicable, connect the neutral wire from both power sources to the switch’s neutral terminal, usually labeled ‘N’. In some cases, the neutral is directly connected to the load and does not pass through the switch.
4. Grounding:
– Ensure that all equipment is properly grounded according to electrical codes and standards.
For an automatic changeover switch, the wiring may also include:
– Control Wires: These connect the switch to the automatic transfer switch controller, which manages the switching process based on power sensing inputs.
– Sensing Wires: These are connected to the utility and generator power sources to monitor the presence and quality of power.
Here is a simplified wiring schematic for a manual changeover switch:
“`
L1 (Utility) L2 (Generator)
| |
| |
[Changeover Switch] [Changeover Switch]
| |
| |
C (Common) C (Common)
| |
| |
Load Load
Check the video of how to wire the changeover switches on Youtube.
It is crucial to follow the manufacturer’s instructions and local electrical codes when installing and wiring changeover switches. Incorrect wiring can lead to equipment damage, electrical hazards, or non-compliance with safety regulations. For safety and compliance, it is often recommended to have a qualified electrician perform the installation.
