Low voltage hot to hot timer

A system for measuring a hot-to-hot load transfer time for a transfer switch on an electrical system including a first power source, a second power source and a load, the transfer switch being configured to transfer supply of power to the load from one of the first and second power sources to the other one of the first and second power sources, the system comprising:

• first and second sensing leads connectable or couplable to the electrical system or a component thereof to monitor a supply of power from the first and second power sources to the load;
• a mode selector for selecting a transfer mode to be implemented by or through the transfer switch from a plurality of different types of transfer modes, the different types of transfer modes including at least a closed transition transfer mode and an open transition transfer mode;
• and
• a controller, coupled to a memory, configured to:
• monitor electrical signals from first and second sensing leads or signals derived therefrom to sense a supply state of electrical power from the first and second power sources to the load, each of the first and second sensing leads being connectable or couplable to the electrical system or a component thereof according to the transfer mode being implemented by or through the transfer switch;
• identify an occurrence of a contact lift and an occurrence of a contact landing, which are associated with a load transfer operation of the transfer switch, from the monitored electrical or signals derived therefrom, the contact lift being an operation of the transfer switch which disconnects one of the first and second powers from the load, the contact landing being an operation of the transfer switch which connects the other one of the first and second powers to the load;
• measure a load transfer time based on a timing of the identified occurrence of the contact lift and the identified occurrence of the contact landing, and the selected transfer mode;
• and
• output the measured load transfer time
• wherein the open transition transfer mode comprises a load transfer scenario where the one of the first and second power sources is connected to the load, the one of the first and second power sources is then disconnected from the load, and thereafter the other one of the first and second power sources is connected to the load to complete the load transfer operation, and
• the closed transition transfer mode comprises a load transfer scenario where the one of the first and second power sources is connected to the load, the other one of the first and second power sources is then connected to the load, and thereafter the one of the first and second power sources is disconnected from the load to complete the load transfer operation.

A non-transitory computer medium storing computer executable code, which when executed by one or more processors, implements a method of measuring a hot-to-hot load transfer time for a transfer switch on an electrical system including a first power source, a second power source and a load, the transfer switch being configured to transfer supply of power to the load from one of the first and second power sources to the other one of the first and second power sources, the method comprising:

• receiving a selection of a transfer mode to be implemented by or through the transfer switch from a plurality of different types of transfer modes, the different types of transfer modes including at least a closed transition transfer mode and an open transition transfer mode;
• monitoring electrical signals from first and second sensing leads or signals derived therefrom to sense a supply state of electrical power from the first and second power sources to the load, each of the first and second sensing leads being connectable or couplable to the electrical system or a component thereof according to the transfer mode being implemented by or through the transfer switch;
• identifying an occurrence of a contact lift and an occurrence of a contact landing, which are associated with a load transfer operation of the transfer switch, from the monitored electrical signals or signals derived therefrom, the contact lift being an operation of the transfer switch which disconnects one of the first and second powers from the load, the contact landing being an operation of the transfer switch which connects the other one of the first and second powers to the load;
• measuring a load transfer time based on a timing of the identified occurrence of the contact lift and the identified occurrence of the contact landing, and the selected transfer mode;
• and
• outputting the measured load transfer time
• wherein the open transition transfer mode comprises a load transfer scenario where the one of the first and second power sources is connected to the load, the one of the first and second power sources is then disconnected from the load, and thereafter the other one of the first and second power sources is connected to the load to complete the load transfer operation, and
• the closed transition transfer mode comprises a load transfer scenario where the one of the first and second power sources is connected to the load, the other one of the first and second power sources is then connected to the load, and thereafter the one of the first and second power sources is disconnected from the load to complete the load transfer operation.