What do time-delay and fast-acting fuses mean?

Could somebody explain the terms: "time-delay" and "fast-acting"?



You may want to read this article: Fuse ratings and Choosing the correct fuse

The answer to your question is as follows:

Time-delay: A fuse in which the burnout action depends on the time it takes for the overcurrent heat to build up in the fuse and melt the fuse element.

Fast-acting: A fuse that opens on overload and short-circuits very quickly. Fast-acting fuse is not designed to withstand temporary overload currents associated with some electrical loads.

how do select the fuse types?

In general a time delay fuse protects a motor from overload while allowing greater starting amperage to get the motor up to speed.

If you are protecting life and property. A fast acting fuse is best for this.