OT: We Really Need A OT.Net Forum For These

[Geospark]

 

[keithkyll]

Keith,
Just so anyone reading quickly doesn't assume you mean all semiconductor fuses should not be used for motor starter applications. You just meant the "Form 101" variety, right? "gG" semiconductor fuses, for instance, would be widely used in motor starter applications. We have some in use here.

Yes, I meant all. It's hard to make a general statement with all the special types available today. Although Form 101 has many applications, it's a very fast blow type. I would use it to protect a SCR in a heater controller, but not on a motor disconnect, but that's just me. From a Form 101 datasheet,
"​ Form 101 Semiconductor Protection fuses were developed for higher voltage AC and DC drives, UPS systems, reduced voltage motor starters and similar applications where lower I2t and superior reliability are needed. " Form 101 link.

Type "gG" is general purpose, not specifically designed to protect Semiconductor devices.

In my opinion, the best fuse for a motor is a dual element, time delay. In motor applications, I don't use fuses. With 3 phase, one fuse blows and single-phases the motor until the next fuse blows. Then maintenance changes 2 fuses, leaving the third, now margined fuse, to nuisance-trip later and repeat the process.
I use contactors and manual disconnects or thermal overloads.

 

[kwade]

https://s-media-cache-ak0.pinimg.co...26ed9a--electrical-wiring-gumball-machine.jpg

The above will show you a picture of a penny used instead of a fuse.

I though that those were 'GI' fuse bushings.

 

[Bering C Sparky]

https://s-media-cache-ak0.pinimg.com/736x/ba/98/b1/ba98b153c42736737959ae151a26ed9a--electrical-wiring-gumball-machine.jpg

The above will show you a picture of a penny used instead of a fuse.

Well that brings back some memories.

A Wadsworth Fuse Panel with 2 wire Cloth Covered Cable that has no ground conductor. Changed out 100's just like this.
(That bare wire you see in there is your water-bond conductor, most homes back in the day had metal pipe for water that ran horizontal in the ground, so generally there were no ground rods used back then. You just bonded the neutral to your water line in the house)

Total of 6 circuits in that one to run the entire house.
Man we have come a long way in a short time.....I bet I have 30 circuits in my panel at home.

I am actually shocked that the couple fuses you see in the picture are 20 amp....normally on those old fuse panels every fuse installed in the screw sockets were 30 amp......that way they would blow less often.

But I suppose the Lincoln Fuse is taking care of that quite well.
Saw this a lot also.....fuse blows, homeowner would shove a penny in there and screw the blown fuse back in to hold her in place.

I am surprised most houses back in the day did not burn to the ground.

BCS