In Part 1, we saw why we must separate overload protection from fault and short circuit protection for motor circuits. But correctly sizing these different devices can be confusing. And if you follow ...

In the original version of this article, the second figure contained an error. The image has been updated. It’s important for engineers to have a good, working ...

One of the more popular three-phase electrical services supplied to medium-size commercial buildings is the Wye or Star configuration transformer. The name comes from the transformer’s secondary ...

This solid-state thyristor (SCR) switch circuit is perhaps the simplest means of reversing a 3 phase motor. “Static” is a catch-all term that essentially means without moving (mechanical) contacts ...

Each motor branch circuit must be protected against short circuit and ground faults by an overcurrent device sized no greater than the percentages listed in Table 430.52. A branch-circuit ...