Someone mentioned the Victron Autotransformer many months back which was a product I had never heard of. And I keep thinking it would be a useful item for balancing my household load across both legs of my generator to avoid risk of overloading one. Has anyone actually done this?
I have a Briggs Q65000 which is 5000 running watts or ~ 21 amps on each leg. It’s quiet and wife can start it without an issue.
Our house is pretty generator friendly in that if we don’t use our electric dryer we don’t have many high current draw loads.
Biggest loads are coffee maker , dish washer and starting loads fridge, freezer, mini fridge, ice maker.
We have two mini splits on 20 amp circuits we can plan our usage of if needed.
Heat is oil baseboard or pellet stove.
Hot water is oil or hybrid electric(2 amp at 240v)
240v well pump and a 120 v sewage transfer pump.
So we have a bunch of of intermittent loads that if on the same leg could be an issue.
$600 is fairly cheap it it means the wife can make her coffee without worrying. Anyone actually added one?
Hello, I was just checking some schematics from an industrial soldering equipment, and I found this three autotransformers, but I don´t know what is their function there. The only application that I know for them until now is of working as a voltage regulator, but you can see that the three autotransformers has a common connection that is not connected to any power source. Can you explain me what do they do there?, are they working just like an variable inductive load for the proper function of the soldering equipment without the function of regulate voltage?
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Hi! I have an oddball question about transformer inrush, generators, and creating split-phase power from single-phase. I'll try my best to keep it as straightforward as possible, but buckle in regardless. I tried this question previously on a couple of electrical-specific subreddits and it didn't go over very well. I apologize in advance to those who find my excessively detailed "it all started when the universe was created" style of writing boring; I do actually speak like this in-person as well.
The Problem
My family's house is powered by a 4KW 48vdc to split-phase 120+120=240vac inverter. The house is wired for a single phase of 120vac so only the inverter's L1 and N are connected. Originally the house was powered by a single-phase inverter. The inverter has an integrated battery charger and transfer switch to simultaneously pass through an external AC source while charging batteries. The inverter allows user-defined current limits to avoid overloading smaller generators. No electrical grid is present.
We're very lucky to have such an expensive and powerful inverter, however, it will only accept split-phase 120+120=240vac input for charging and passthrough. Occasionally the weather is very poor for an extended period of time. During those periods we'd like to charge our batteries off a generator. We possess a 2.5KW single-phase 120vac inverter generator and a 2.3KW single-phase 120vac alternator generator. Two companies manufacture autotransformers capable of, among other things, accepting 120vac on one end and outputting 120+120=240vac on the other end. Purchasing or building a new split-phase generator costs as much as a car and we wish to avoid this option, using an existing generator, as an autotransformer is much less expensive and adds versatility.
The Actual Question
I am concerned about the inrush current the generators would experience when energizing the autotransformer. Before the initial magnetic field develops, the transformer will potentially draw an absurd amount of inrush current depending on when in the AC cycle the connection is made. I'm concerned that this could have a number of undesirable effects:
- Inverter in I
Hey guys, I am wondering if anyone knows any rules or has any experience with using delta wye transformers (or any other relatively common transformer) to make their own autotransformers?
Basically, can you legally take a 600V / 120/208V 3 ph delta wye and hook it up to make a 600 V / 480V 3phase delta auto-transformer?
Gut tells me no but I can't find any concrete answer.
I found a NEC rule describing infield autotransformer connections but I am not convinced it's talking about what I mean.
Hello! I have a few questions if someone knowledgeable would be so kind. For all of the above, assume that I'm inputting single-phase 120V 60Hz north american AC:
- No matter what the knob setting, is the output 60Hz?
- Is the output a "perfect sine wave" like the input, or does it get all chopped up?
- Is there any potential between the low side of the output and the low side of the input (the neutral)? Are the input/output zero degrees out of phase?
- You know how for 120VAC it's 120V RMS, and the voltage actually goes from -170 to +170? Does the same thing happen with a variac, e.g. does setting the knob at 60V have it cycle between -85 and +85V?
- Is there a such thing as an autotransformer where there's a knob for voltage and one to vary the frequency too?
Thank you! As you can tell from these questions, I'm buying my first for my little electronics lab and want to make sure I know what I'm getting. The youtube vidoes I watched and the wiki didn't answer the above questions. Thanks.
Trying to find a decent autotransformer in the 15-20A range, without breaking my budget.
Are those cheap red ones on Ebay any good?
If I have a two-winding transformer with a 2400/240 kV rating for example and I am to implement it as a step-up additive autotransformer, will the transformer voltage rating change? Once transformed, the low voltage side would be 240 and the high voltage side would be 240 + 2400 = 2640 turns. Will the rating change to 2640/240 kV? I have a homework regarding this transformation and it says that "the load has a rated voltage" and it confuses me.
EDIT:
to be implemented as a step-up additive autotransformer*
Hi all,
I am currently working on a school project where we are building a solenoid launcher based on the Thompson Jumping Ring Experiment. This essentially has us plugging a solenoid (around 200 turns, ~50-60 feet of copper wire 1mm diamater) into a 120VAC wall outlet. As a result, the resistance of this who apparatus is very small. As is, our setup launches a small aluminum ring about seven feet into the air.
Our goal is to be able to vary the performance of our launcher by changing the power supplied to it. The initial idea was to use a transformer that would allow us to step down the voltage, but this is where I get a bit unsure. A variable transformer will vary the voltage supplied to the solenoid, but what I'm concerned about is the current that is running through our solenoid since that's what makes the application work. If the variable autotransformer is supplied with a constant power, lowering the voltage (with a constant resistance) will cause the current to increase to maintain that constant power. While we haven't measured the current going through the solenoid (we'll hopefully be doing that soon) we suspect that it is quite high due to our extremely low resistance. Most variable autotransformers we've seen have a current rating of around 10A, so my main concern is if we lower the voltage supplied to our launcher with a constant power, we'll pretty much always go above the current rating for the variable transformer and blow the fuse. Does anybody have any expertise or advice concerning this? Thanks
I've been searching for a bench variac (10A and up) for a number of electronic projects with my classmates, and we've struggled to find a decent one that's under $150. As I haven't had as much experience shopping for larger equipment, I've wondered if you all had any suggestions on a proper place to look.
P.S. I would also like to thank you guys for being a terrific community. I haven't posted here before, but I'm always on here looking for cool projects, motivation, and advice, and I've always been surprised.
I’m having trouble understanding exactly the “separately derived system” thing
I have a generac 22kw generator feeding the victron Quattro 48v 230v 15kw inverter
Since I have the European 220 AC in on the inverter I’m just running both hot legs of the generac and ignoring the neutral.
The inverter is grounded to the same rod as the circuit box
Do I need to bond the neutral in the generator over to ground? Or does that present danger
Do your worst!
This techcrunch article on charging company offerings at CES includes some V2G and/or V2H offerings. Some of them are based on pulling DC from the CCS port, and having an inverter as part of the EVSE (e.g., Wallbox Quasar 2), and some are based on the car having a bidirectional OBC that can feed AC back to the grid through a level-2 EVSE, such as the new Blink HQ200 (also discussed in this previous post). Nuvve also has a product for that type of operation.
Blink only mention grid-connected operation (V2G), whereas Wallbox mentions V2G and V2H, and specifically calls out the situation of powering a house when the grid is down. There are of course issues of ensuring that you are disconnected from the grid, and having the code-required disconnects for V2H operation that Wallbox hasn't provided much detail on yet, but I realized there's another reason why people aren't talking about the AC option (with bidirectional OBC) being used for V2H: If you are sending AC backwards through J1772 connectors, there's no neutral. You can feed power back to the grid with no neutral, but if you have disconnected from the grid and power up a house without the neutral connected at the source, it won't work for 120 V loads (and will likely blow up lots of them).
So I think that's why the DC-V2G systems, with an off-board inverter, are the ones advertising V2H.
You could, or course, add an autotransformer to create a neutral, but that would add cost, require space, and waste energy when you were running in the V2H mode, draining the battery a little faster.
I'd bet that the general public will be more likely to be interested in buying the V2H feature than the V2G feature, unless power companies start offering good, easy to understand incentives for V2G.
The MPP Solar V2-5048 looks perfect for me on paper, except that its 220v only. It allows chaining 9 of them which basically means you could max out a 200amp service. It is grid tied, but has battery backup and generator backup abilities. It allows up to 450v of solar input, which means easier wiring. Is there a version of this that works for the US market? Is there some type everyone would recommend? I am trying to plan out my system. My solar won't be mounted on my house, so I am not worried about the instant shut down of each individual panel, etc.
Hi! I have an oddball question about transformer inrush, generators, and creating split-phase power from single-phase. I'll try my best to keep it as straightforward as possible, but buckle in regardless because I need to set the scene first.
The Problem
My family's house is powered by a 4KW 48vdc to split-phase 120+120=240vac inverter. The house is wired for a single phase of 120vac so only the inverter's L1 and N are connected. Originally the house was powered by a single-phase inverter. The inverter has an integrated battery charger and transfer switch to simultaneously pass through an external AC source while charging batteries. The inverter allows user-defined current limits to avoid overloading smaller generators. No electrical grid is present.
We're very lucky to have such an expensive and powerful inverter, however, it will only accept split-phase 120+120=240vac input for charging and passthrough. Occasionally the weather is very poor for an extended period of time. During those periods we'd like to charge our batteries off a generator. We possess only a 2.5KW single-phase 120vac inverter generator and a 2.3KW single-phase 120vac alternator generator. Two companies manufacture autotransformers capable of, among other things, accepting 120vac on one end and outputting 120+120=240vac on the other end. Purchasing or building a new split-phase generator costs as much as a car and we wish to avoid this option, using an existing generator, as an autotransformer is much less expensive and adds versatility.
The Actual Question
I am concerned about the inrush current the generators would experience when energizing the autotransformer. Before the initial magnetic field develops, the transformer will potentially draw an absurd amount of inrush current depending on when in the AC cycle the connection is made. I'm concerned that this could have a number of undesirable effects:
- Inverter in Inverter Generator too sensitive and trips out due to perceived short
- Breaker in Inverter Generator electromagnetically trips
- Breaker in Alternator Generator electromagnetically
