The utility said they were OK. They no longer allow using the Earth as a return path because of possible electrocution. The soil is sandy, so it would require multiple ground rods to be driven into the Aquifer. That is over 100 feet deep around here.
A three phase motor is easily damaged by undervoltage,or by a missing phase . The current on the bad leg goes up, and damages the winding. Look at Rota ry Phase Converters. You can use a running three phase motor as a rotary tr ansformer, but it must be derated and running at speed before connecting an other three phase load to it. A small pony motor starts it, and a bank of A C rated capacitors is used to balance the three phases.
My AC uses a VFD to soft start and control the compressor speed. It is 120V AC only.
Does that mean you do have ground rods, but that the neutral & ground aren't tied together in the panel? Or do you not have ground at all?
Mike, this is perhaps silly. 'cause I'm not sure I understand all the details of AC power. But can you balance the load on the two phases? (run an extension cord into the computer room?) At least as a temporary measure.
George H.
There are ground rods, but they are only intended to carry fault currents. The neutral is a seperate system that is only bonded at the master panel. I n my case, that panel is directly below the meter base. If they are bonded in more than one spot, the safety ground wiring will be carrying current. I R losses will raise that system above zero volts wich can cause unsafe cond itions.
George, it could be done with static loads but dynamic loads would require you to waste a lot of power to operate properly. Even 10% regulation would be difficult and expensive. If the situation were long term I would have du g out an old 750VA power transformer with dual 120VAC primaries and connect ed it as an autotransformer to synthesize a temporary neutral. Given that t ransformer needs a dolly to move it and it hums, I didn't want it next to m y bed.
Ok, but I was suggesting running your critical 120V loads via a
240V:120V stepdown isolation (not auto-) transformer from 240V, on the assumption that the 240V supply will be stable in spite of a bad neutral connection between your house and the utility's transformer. This is not as good as getting the utility to fix the problem with the neutral, but might be an option if they won't.
e you to waste a lot of power to operate properly. Even 10% regulation woul d be difficult and expensive. If the situation were long term I would have dug out an old 750VA power transformer with dual 120VAC primaries and conne cted it as an autotransformer to synthesize a temporary neutral. Given that transformer needs a dolly to move it and it hums, I didn't want it next to my bed.
Thanks Michael. If it was long term maybe a little 240 to 120 transformer that could run your 'puter and such.
George H.
A lot of computer power supplies will run from 240VAC without any modifications.
Ah yes, how times have changed. It seems like only yesterday that computer PSUs, TVs and many other consumer electronic products using AC power had a slide switch at the back for switching between 110/120V and 220/240V. Some even had a coin slot rotary selector with half a dozen positions from 100V to 250V.
At least that's the way it was with products from the East.
Add a new air conditioner to the damage costs. It ran but didn't cool after power was restored. Now it won't even run the fan. A new one from Sam's Cl ub is slightly under $250, delivered. Now I'll need a couple people to help swap it out. The whole house system was installed with flex duct. It was f ull of holes within a year. The last time that I tried to use it, there wer e dry leaves blowing from every open duct.
My son-in-law's 3 story house in old Toronto uses modern PVC pipes for AC air flow which then reduces to 3/4" distributed in the ceilings.
The advantage is that it increases the air velocity which speeds up the diffusion of cold air and yet is silent without blower or wind noise and you can quickly feel it and the exit holes are barely noticeable.
You could balance with with an autotranformer between phases with the centre-tap connected to neutral. it'd need to be big enough to handle the largest imbalance. and would probably be harder to organise than getting the power company out to fix the neutral.
It's a shame that the CATV cable proved to be a better ground than the ground rods.
-- Jasen.
A shame? It did exactly what it was designed to do. To fail in a safe condition. You sound like someone who would use old black iron pipes full of natural gas to ground a building.
If they'd had some sort of isolation on it it would have survived and not deprived you of internet
-- Jasen.
You are a dangerous fool. How do you provide isolation, grounding and light ning protection on a piece of coax? The NEC requires ground. Any component of consumer electrical hardware must withstand a 10,000A fault current with out damage. That same coax would have had to carry up to 200A continuous to replace the open neutral. Also, a condition like that could kill someone w orking on the. CATV system. I would never want to work anywhere that you've ever worked.
I'm confused: didn't the service neutral open, allowing the house neutral to become energized by unbalanced loads on the 2 legs? If so, that doesn't seem safe to me.
He was talking about the cable TV coax carrying the neutral after the failu re. THAT would be dangerous, plus it would have to carry up to 200A to main tain the electrical service. They are supposed to be here in a few hours to install a temporary cable. I am running it a different route, and in condu it.
Cable company refused to run temporary drop, and left.
You are a poor judge of character, and nasy with it too, but I'll give that a pass this time.
Transformers tend to work well for isolation.
huh? Did the coax withstand that?
Are you under the miaprehension that I was suggesting that it should?
If the coax to your hole had been isolated from the CATV distribution wiring there would have been no fault current there and your internet would have been restored sooner.... I'm starting to wonder why I immagined that that could have been a benefit.
2A is as deadly as 200A. How much did it take to melt your coax? presumably the coax fitters are trained to be safe around fault currents. (as are plumbers etc.)Yeah, staying away from things you don't understand is a good policy.
-- Jasen.
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