[BlownYenko]

My electric fan fuse gets hot quickly, and the fans won't run for more than a minute before they become intermittent. Seems that a bad fuse connection would be the most likely culprit if the fuse is hot but not blowing so I'll get that sorted.

I'm worried that the fuse is physically too large for the fuse holder. Surely it's not ideal to be able to see the fuse "legs"? The fuse holder seems too deep to fit a standard blade fuse in there. Is this something in between the standard case fuse and blade fuse sizes?

Here it is:

Photo
of the fuse...

 

[CRUZN69]

That's a circuit breaker not a fuse. It gets over loaded and trips. Cools off and works again. Might be wired wrong. The power is supposed to go through the relay right next to it.

 

[BlownYenko]

Thanks Rick. As I can't tell the difference between a fuse and a circuit breaker, it's fairly obvious that I am a complete wiring/elec novice!

The fans have been fine for months, so I'd assume that the wiring between the circuit breaker and relay should be OK.

I removed the circuit breaker today and fitted the same amp blade fuse (30A). The fuse lasted a split second before it blew... I fitted the circuit breaker again and it ran the fans for about 3 minutes before it started tripping/resetting.

What would cause a fuse to blow instantly, but allow a circuit breaker to operate for a few minutes?

 

[onovakind67]

What would cause a fuse to blow instantly, but allow a circuit breaker to operate for a few minutes?

It takes a while for the CB to heat up enough to trip while the fuse is designed to trip quickly. The inrush current to the motor probably exceeds the fuse rating, but the CB will absorb this and trip on the average current through the motor.