What’s inside counts

Anu-Riikka Maki

Switch fuses are essential safety products that enable everybody to enjoy the benefits of electrical power in safety.

The switch enables you to turn circuits on and off, and if there’s a fault or an overcurrent, the fuse blows, isolating the circuit to contain any damage.

It’s a brilliantly simple concept. You just toss the old fuse, slot in a new one and turn the power back on again. So how can you possibly improve on it?

What makes ABB’s switch fuses better

The thing is there are two main parts to a switch fuse. There’s a switch and a fuse – and people forget about the switch. People just replace the fuse and take it for granted that the switch has not been affected by the short circuit. The handle is still working after all.

A key difference between ABB switch fuses and competitor products is in the design of the switch contacts. Cut open a competitor switch and you will see that it just pushes two contact plates together.

Overcurrents try to push these plates apart, which can create an arc and damage the contact surfaces. The result is that, inside the switch, the contacts are ageing faster and becoming more prone to arcing.

Switch fuse design engineers know this and have a choice. They can either accept the imperfection and the cost savings, or you can make a better product that solves the issue. That’s what makes product design work at ABB so cool.

The ABB difference

ABB’s solution is a better contact design. From the outside, the difference is not obvious. But when you turn the handle on an ABB switch fuse, instead of pressing of two plates together, a knife-shaped contact completes the circuit, wedging itself into the opposing V-shaped contacts.

Unlike competitor switches, overcurrent cannot force the contacts apart. And the design is self-cleaning: whenever the user turns the product on or off the motion wipes the contacts.

The design costs a little more to produce, but it is also why ABB switch fuses achieve higher current ratings and voltages. The knife contact also enables them to go beyond the basic needs of power distribution, providing the higher levels of protection needed in more demanding applications like very heavy-duty electric motors.

Switch fuses are everywhere and most people take what’s inside for granted. For ABB, that makes it all the more important to design them better.

 

ABB switch fuses: World class performance in the most demanding applications  

About the author

Anu-Riikka Maki

I have been working in ABB’s Protection and Connection business for 4 years. The first 3.5 years I spend in R&D as design engineer in transfer switch team and now, few months ago I started as Global Product Manager of switch fuses and fuselinks. For our customers we aim to offer products that reflect quality, high performance and are user friendly. I am intrigued of the possibilities of the fuse technology in combination with switches and therefore motivated to promote the benefits of the duo
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