New digi OCPD's

[FionaZuppa]

A good read

https://www.popularmechanics.com/te...tal-circuit-breaker/?utm_source=pocket-newtab

 

[Jraef]

There are already a couple of other threads on this subject and lots of opinions already expressed.
https://forums.mikeholt.com/showthread.php?t=198218
https://forums.mikeholt.com/showthread.php?t=198287

This article has something worth discussing though:

Picture the fuse box in your basement, each switch assigned to different electrical components of your home. These switches are designed to break a circuit to prevent the overloaded wires in your wall from overheating and causing a fire. When this happens, you plod down to your mechanical room and flick the switches on again.

So I suppose IF you still have a "fuse box in your basement" and have somehow never heard of a CB panel, the concept of having switches for each load is somewhat different.

Now multiply that simple system in your home to city high rises and industrial buildings, which might have 250 circuit breakers on any given floor, each one ranging from 15 to 4000 amps at higher voltages. At this scale, the limitations and dangers of a manually controlled power system become much more evident—and costly.

The second paragraph though is the one that gets me, especially the last sentence (highlighted). That statement essentially attempts to ESTABLISH "limitations and dangers" by implying they exist, then falsely alludes to the fact that THEIR system is the only way to avoid said "limitations and dangers".

Pure marketing BS...

I also like how they are claiming to be "the first" when in fact many of the traditional circuit breaker mfrs have had this available for some time, it's just that as a general rule, the added cost makes it something that almost nobody buys. That's why I think their marketing approach is to try to create some new "danger" that only their product can protect against. It's a story as old as time.

 

[gadfly56]

They are claiming interest from Siemens, ABB, and Eaton. If you thought AFCI's were expensive, wait until these hit the committee.

 

[Jraef]

They are claiming interest from Siemens, ABB, and Eaton. If you thought AFCI's were expensive, wait until these hit the committee.

"Interest" could just be that they want to know whether these guys are a serious threat or not...

I have used ABBs network controllable breakers but as I said, the cost was prohibitive for anything but "gold plated" projects.

 

[gadfly56]

"Interest" could just be that they want to know whether these guys are a serious threat or not...

I have used ABBs network controllable breakers but as I said, the cost was prohibitive for anything but "gold plated" projects.

What, exactly, is their selling point? It can't be that you can re-route a circuit to a different breaker (shades of Star Trek!), and is any fault you encounter going to overwhelm traditional breakers? Aside from lightning strikes and the occasional 19.6 kV line dropping onto a residential connection. And would digital breakers even help in those cases?

 

[Jraef]

What, exactly, is their selling point? It can't be that you can re-route a circuit to a different breaker (shades of Star Trek!), and is any fault you encounter going to overwhelm traditional breakers? Aside from lightning strikes and the occasional 19.6 kV line dropping onto a residential connection. And would digital breakers even help in those cases?

In theory, if you have an energy monitoring system, network controlled breakers can be used to monitor specific circuit use and then to shed loads. The digital part of these breakers is not the only aspect of them that's different, it's just the thing they are carrying on about. The other aspect that makes them different is that they don't need a motor operator to turn them on. They use an SCR as the main switching device, then they have a small bypass contact to avoid having them overheat and an isolation device ahead of them that only opens under a trip condition, not during a simple On-Off operation. So each pole is actually a relatively complicated power circuit: isolation contact, SCR, bypass contact, SCR firing board, digital interface board, power measurement system and user interface. Translate; $$$

Sounds like a decent plan (albeit not cheap), but having been in the soft starter business for a couple of decades, I can attest to the fact that SCRs are not very forgiving of line transients, so most likely people will be replacing these things a LOT. Combine that with a high price and I don't see them taking off.

 

[FionaZuppa]

SCR? Or IGBT? VFD's are mainly IGBT's and get hit with motor turn on's and off's. Solid state is sensitive to both on and off. Still an interesting shift in the OCPD technology.

In theory, if you have an energy monitoring system, network controlled breakers can be used to monitor specific circuit use and then to shed loads. The digital part of these breakers is not the only aspect of them that's different, it's just the thing they are carrying on about. The other aspect that makes them different is that they don't need a motor operator to turn them on. They use an SCR as the main switching device, then they have a small bypass contact to avoid having them overheat and an isolation device ahead of them that only opens under a trip condition, not during a simple On-Off operation. So each pole is actually a relatively complicated power circuit: isolation contact, SCR, bypass contact, SCR firing board, digital interface board, power measurement system and user interface. Translate; $$$

Sounds like a decent plan (albeit not cheap), but having been in the soft starter business for a couple of decades, I can attest to the fact that SCRs are not very forgiving of line transients, so most likely people will be replacing these things a LOT. Combine that with a high price and I don't see them taking off.

 

[Jraef]

SCR? Or IGBT? VFD's are mainly IGBT's and get hit with motor turn on's and off's. Solid state is sensitive to both on and off. Still an interesting shift in the OCPD technology.

They are SCRs. IGBTs switch DC, not AC. The output of a VFD only LOOKS LIKE it is AC to an inductive load, like a motor.

 

[FionaZuppa]

They are SCRs. IGBTs switch DC, not AC. The output of a VFD only LOOKS LIKE it is AC to an inductive load, like a motor.

??
I use mosfet SSR's to turn on/off AC loads all the time.
Mosfets or IGBT's can be used in SSR.
Many ways to control AC using solid state devices.