Delay

A delay, or slow-blowing, fuse has a built-in delay that is activated when the current through the fuse is greater than the current rating of the fuse. This fuse will allow temporary increases in current (surge) without opening. Some delay fuses have two elements; this allows a very long time delay. If the over- current condition continues, a delay fuse will open, but it will take longer to open than a standard or a fast fuse.

Delay fuses are used for circuits with high surge or starting currents, such as motors, solenoids, and transformers.