3 ms·

"Just plug into a wall outlet", it says. Hmmm... I have to say, this doesn't smell correct. If this is safe, than it's useless. If it provides enough power

"Just plug into a wall outlet", it says. Hmmm... I have to say, this doesn't smell correct. If this is safe, than it's useless. If it provides enough power to be useful, than it's unsafe. 1) You have to sync to the grid, and if you go out of sync by more than x%, you have to automatically disconnect to protect the grid. Are they doing this? If they're not, it's because their power output is so miniscule that nobody cares. 2) You have to provide ability for line workers to guarantee that you aren't back feeding power onto a line they had turned off and so thought was safe to work on. Are they doing this, or, again, is it a don't care because they're only producing 5 watts or some equally silly power. I imagine these devices to be so ridiculously low power, that items 1 and 2 are don't cares. However, are they so low powered that we don't even care about risk to the house itself? Plugging into a wall outlet bypasses the breaker-box in the house, Say that you're producing 10A of current with your little device. If your breakers are 15A breakers, now they won't trip until 25A of current is running through that circuit. My gut feel is that the answer to all these questions is, nobody cares, because they produce embarrassingly low amounts of power which means they're just a way to get rich off of environmental guilt.... Thinking about it that way, I'm all for it.

robotrout 17y ago
Another thing is that the grid power is 3 phase. Your wall outlets are single phase or, at best two phase (for your dryer and oven). So, even if all other considerations were ignored, you're feeding unbalanced power back onto the grid, by not adding power to all three phases.
- coryrc 17y ago
  1. Nearly every house in the US is on a single 240V phase with a center-tap to create 120V. Any load is already unbalancing the three-phase transmission lines. Luckily, throwing a similar number of houses on each phase balances out. But if all the houses on one phase turned on their electric heaters and ovens and the houses on the other phases turned off everything, you'd have one unbalanced transformer, but the grid would still remain within tolerance. Now, if you picked a good 10,000 houses all on a single phase spread across a service area, maybe you'd begin to have a detectable problem. 2. Your outlets are spread semi-randomly around to each half, so if you only plugged things in one half, you could only draw half the rated power before blowing the breaker. So it's not a problem, as you seem to imply.
  - robotrout 17y ago
    1. I'd be interested in where your number of 10,000 houses comes from. 2. The breakers I was referring to were your circuit breakers in your breaker box. My concern being with their ability to do their assigned task of protection.
falsestprophet 17y ago
The worst part about this is the company knows full well that their product is useless. Their entire business model is taking advantage of guilt and ignorance. He is no Thomas Edison. So, I suppose he is a lot closer to Don Quixote.
coryrc 17y ago
>You have to sync to the grid ... > You have to provide ability for line workers to guarantee that you aren't back feeding power onto a line they had turned off ... Most solar inverters do this. It is very easy. They don't start adding power to the line until a little past a zero crossing, which solves both the sync issue and the line down issue. > Say that you're producing 10A of current with your little device. If your breakers are 15A breakers, now they won't trip until 25A of current is running through that circuit. Only partially true, depending on where you measure the amperage, but I doubt it'd be UL and/or NEC approved to be on anything but a dedicated circuit. If the device is the first thing after the breaker, then 25A could be flowing on the load side of the breaker. However, if it's the last thing in the circuit, the setup is completely safe. No way to assure this, of course, unless it is a dedicated circuit.
- robotrout 17y ago
  > start adding power to the line until a little past a zero crossing That sounds technically sound. Is it compliant with power company rules? The reason I ask is that I looked into setting up a wind generation business 20 years ago, building windmills in Wyoming and selling back to the power company. The power company required special "blessed" devices between user generation equipment and the grid to protect the grid. This usually took the form of sensing circuitry and a physical relay that could completely isolate the grid from your equipment if necessary. Doing everything in silicon with MOSFETS and algorithms is definitely technically feasible, but lacks the fail-safe behavior of physical isolation on demand. I'm surprised that they allow this.
tlb 17y ago
Don't worry about too much power. A 5' diameter turbine (quite a project to install) might generate 600 watts in a stiff 35 mph wind.

robotrout 17y ago

Another thing is that the grid power is 3 phase. Your wall outlets are single phase or, at best two phase (for your dryer and oven). So, even if all other considerations were ignored, you're feeding unbalanced power back onto the grid, by not adding power to all three phases.

coryrc 17y ago
1. Nearly every house in the US is on a single 240V phase with a center-tap to create 120V. Any load is already unbalancing the three-phase transmission lines. Luckily, throwing a similar number of houses on each phase balances out. But if all the houses on one phase turned on their electric heaters and ovens and the houses on the other phases turned off everything, you'd have one unbalanced transformer, but the grid would still remain within tolerance. Now, if you picked a good 10,000 houses all on a single phase spread across a service area, maybe you'd begin to have a detectable problem. 2. Your outlets are spread semi-randomly around to each half, so if you only plugged things in one half, you could only draw half the rated power before blowing the breaker. So it's not a problem, as you seem to imply.
- robotrout 17y ago
  1. I'd be interested in where your number of 10,000 houses comes from. 2. The breakers I was referring to were your circuit breakers in your breaker box. My concern being with their ability to do their assigned task of protection.

falsestprophet 17y ago

The worst part about this is the company knows full well that their product is useless. Their entire business model is taking advantage of guilt and ignorance. He is no Thomas Edison. So, I suppose he is a lot closer to Don Quixote.

coryrc 17y ago

>You have to sync to the grid ... > You have to provide ability for line workers to guarantee that you aren't back feeding power onto a line they had turned off ... Most solar inverters do this. It is very easy. They don't start adding power to the line until a little past a zero crossing, which solves both the sync issue and the line down issue. > Say that you're producing 10A of current with your little device. If your breakers are 15A breakers, now they won't trip until 25A of current is running through that circuit. Only partially true, depending on where you measure the amperage, but I doubt it'd be UL and/or NEC approved to be on anything but a dedicated circuit. If the device is the first thing after the breaker, then 25A could be flowing on the load side of the breaker. However, if it's the last thing in the circuit, the setup is completely safe. No way to assure this, of course, unless it is a dedicated circuit.

robotrout 17y ago
> start adding power to the line until a little past a zero crossing That sounds technically sound. Is it compliant with power company rules? The reason I ask is that I looked into setting up a wind generation business 20 years ago, building windmills in Wyoming and selling back to the power company. The power company required special "blessed" devices between user generation equipment and the grid to protect the grid. This usually took the form of sensing circuitry and a physical relay that could completely isolate the grid from your equipment if necessary. Doing everything in silicon with MOSFETS and algorithms is definitely technically feasible, but lacks the fail-safe behavior of physical isolation on demand. I'm surprised that they allow this.

tlb 17y ago

Don't worry about too much power. A 5' diameter turbine (quite a project to install) might generate 600 watts in a stiff 35 mph wind.