My Generator Study

[Voicy]

https://www.businessinsider.co.za/most-popular-generator-south-africa-ryobi-55-kva-2019-3

"The Japenese-made Ryobi 5.5 kVA generator, which provides up to 6,900 watts of electricity, is one of the most popularly sold generators in South Africa right now, most South African hardware stores agree."

I would love to see how they squeeze 6,9kW out of a 5,5kVA Jenny. That figure should be more like 4,4kW. (Going by the standard 0.8pF)



They probably mixed kVA with kW since it says 6900K on the gen. But then you're still only getting 5,5kW from it. Which is maybe why some are complaining that it underperforms.

 

[Trust|Nobody]

"The Japenese-made Ryobi 5.5 kVA generator, which provides up to 6,900 watts of electricity, is one of the most popularly sold generators in South Africa right now, most South African hardware stores agree."

I would love to see how they squeeze 6,9kW out of a 5,5kVA Jenny. That figure should be more like 4,4kW. (Going by the standard 0.8pF)

I think they are mistaken. The manufacturer's spec states the RG-6900K is rated for 5 kW.
Unless they are referring to the RG-7900K, but the image on the article shows RG-6900K.

They're only journalists

View attachment 636060

 

[lestoran]

So i've been reading a bit about generators (and load shedding solutions in general) both here and elsewhere but there's a lot of conflicting information out there.

To my understanding:

• non-inverter generators
  • use the same amount of fuel regardless of how much load is placed on it
  • there a minimum load that you must put on it
  • running too close to to the minimum too often means more servicing / shorter lifespan
  • without avr its not safe to connect to sensitive appliances
  • with avr power "quality" is close to inverter / eskom power
  • an inverter (with batteries) in front of a non-avr generator will clean up power so its safe to use with sensitive electronics
• inverter generators
  • use less fuel under less load but not as much less as the load is less
  • there's still a minimum load
  • the generator can spin down if there's less load so a lower load wont affect lifespan / service intervals
  • they are safe to connect to just about anything

Am I on the right track here?

 

[Geoff.D]

Please excuse the terrible drawing, but it equates to something like this:

View attachment 636316

Your "3 position selector switch" can be something like this:

View attachment 636318

The 3 position is so that you have:
1 - Mains
0 - OFF
2 - Gen

The OFF position allows safe switching in order to avoid spikes on any equipment - and to avoid any possibily of mains and gen ever coming into contact. This sometimes happens on 2-position switches.

Keep in mind that this selector must be rated to take your full mains capacity as it will be a permanent fixture.

The "Mains ON" / "Gen ON" indicators can either be a 230V buzzer or a lamp, or both in one like this:

View attachment 636320

I added protection circuit breakers for it - which comes in handy if you want to switch off a noisy buzzer. But the buzzer / lamp helps you see when you have mains or gen power at the inputs of your selector switch. If you don't go for a buzzer (or maybe even a buzzer that you can silence) you can leave the lamps on.

You can choose to have a permanent cable running to your Gen's output, or a dedicated socket that leads from the selector switch to your gen and nowhere else.

So if Eskom loadsheds you, you:

1) Start the Gen.
2) Check the status lamp to see that you have gen power.
3) Switch the selector from 1 "Mains" to 0 "OFF".
4) Wait a few seconds to allow fridge motors etc to stop completely.
5) Switch the selector from 0 "OFF" to 2 "Gen".

When you see the "Mains ON" lamp or buzzer activate, you can use the selector to switch back to Mains. Keep in mind that it's worth waiting a few minutes to see that the mains is stable...also allow a few seconds "OFF" to allow motors and such to stop completely before activating the mains.

EDIT: I forgot to change the title of SW4 to whatever your main circuit breaker in your DB is called. SW5 and SW6 are 2Amp circuit breakers - not used for anything other than monitoring the availability of each supply.

Functionally the diagram is "okay" BUT it does not easily translate into a practical understanding of how to integrate the wring into an existing power distribution system in a home. it needs more explanation than that especially as relating to where all this is located, and how it varies depending on how your main power is supplied.

The "Mains CB" is typically a single pole CB in your meter box, or, in a box provided for a prepaid meter.
The Geni CB is the CB on the generator also mostly a Single pole breaker.
That means you have to ensure that the neutrals from the geni and the Mains are bonded.
The symbol you have is not the correct one for a changeover switch with an OFF position between the two states.

SW4 would be either an isolator and E/L double pole switch or both ( as is very common on older homes..

This diagram makes quite a few "assumptions"
1. That user will know that you can't move the changeover over from geni to mains without waiting a few seconds in the middke position.
2. That this type of board will typically be outside of the home, close to where the Geni is situated, which should be at a place conveniently situated to be able to transfer over from mains to geni power.
3. The diagram also assumes that anyone using this setup will either have a geni capable of taking over ALL the load as connected OR, before switchover, all unnecessary power CBs are switched off.

So no, I don't really like the diagram as it is open to abuse and interpretation.

 

[Geoff.D]

"The Japenese-made Ryobi 5.5 kVA generator, which provides up to 6,900 watts of electricity, is one of the most popularly sold generators in South Africa right now, most South African hardware stores agree."

I would love to see how they squeeze 6,9kW out of a 5,5kVA Jenny. That figure should be more like 4,4kW. (Going by the standard 0.8pF)

View attachment 636366

They probably mixed kVA with kW since it says 6900K on the gen. But then you're still only getting 5,5kW from it. Which is maybe why some are complaining that it underperforms.

absolutely correct! Whoever prepares the MBS for sellers of this sort of stuff should be hung drawn and quartered and burnt at the stake for all the incorrect info they publish.

MBS = Marketing BullSchit

brings me to a definition of what Marketing is:
"It is the art of turning BullSchit into Prose".

 

[Voicy]

Functionally the diagram is "okay" BUT it does not easily translate into a practical understanding of how to integrate the wring into an existing power distribution system in a home. it needs more explanation than that especially as relating to where all this is located, and how it varies depending on how your main power is supplied.

You're pretty much on the button with most of those points.

The "Mains CB" is typically a single pole CB in your meter box, or, in a box provided for a prepaid meter.
The Geni CB is the CB on the generator also mostly a Single pole breaker.
That means you have to ensure that the neutrals from the geni and the Mains are bonded.
The symbol you have is not the correct one for a changeover switch with an OFF position between the two states.

The crappy online tool I used to draw it with didn't have changeover symbols.

SW4 would be either an isolator and E/L double pole switch or both ( as is very common on older homes..

Agreed.

This diagram makes quite a few "assumptions"
1. That user will know that you can't move the changeover over from geni to mains without waiting a few seconds in the middke position.

It's not a "cant'" as much as a "shouldnt", but thats why I included some back info.

2. That this type of board will typically be outside of the home, close to where the Geni is situated, which should be at a place conveniently situated to be able to transfer over from mains to geni power.

Not necessarily. A box can be constructed that only includes the changeover switch and indicator lights. All other CBs etc are existing. It can be mounted next to the existing DB (as we did at my mate's house), where you divert your mains through it. Same counts for the Gen.

3. The diagram also assumes that anyone using this setup will either have a geni capable of taking over ALL the load as connected OR, before switchover, all unnecessary power CBs are switched off.

That probably goes without saying, but yes, you'd have to prioritize load before switching on your gen. Of course you could always rewire the DB to have essential and non-essential circuits, but now we're getting in deeper than what could be fixed with a A4 checklist.

So no, I don't really like the diagram as it is open to abuse and interpretation.

You're 100% correct here. It was probably not the best idea to post this on an open forum, as it was intended to give @dennis.se.foon a picture of how it worked - and not a "how to" catch-all guide.

 

[Voicy]

Oooh. Just found an SA site that builds just such panels. (I promise Im not getting paid by them.)

https://www.bundupower.co.za/mcs.php



Mount one of those. Feed your mains into one side, gen into the other side and "common" out to your DB.

And of course as GeoffD mentions, switch off your kettle and arc welder in the garage before doing this.

 

[Geoff.D]

So i've been reading a bit about generators (and load shedding solutions in general) both here and elsewhere but there's a lot of conflicting information out there.

To my understanding:

• non-inverter generators
  • use the same amount of fuel regardless of how much load is placed on it (There is a slight reduction in fuel use when "spinning" as compared to under load. Basically the same as in a motor car, the harder you drive the more fuel you use).
  • The speed at which the motor runs (rpm) determines the frequency of the supply, determined by the governor and how quickly it reacts to changes in load. It is the frequency that will affect and possibly damage power factor sensitive equipment such as fridge compressors etc. the rpm also affects the output voltage
  • there a minimum load that you must put on it
  • running too close to to the minimum too often means more servicing / shorter lifespan
  • without avr its not safe to connect to sensitive appliances ( AVR helps to stabilise the voltage as well as the frequency)
  • Maintenance however is the key, Good maintenance of the geni will make sure the geni is srunning optimally.
  • with avr power "quality" is close to inverter / eskom power
  • an inverter (with batteries) in front of a non-avr generator will clean up power so its safe to use with sensitive electronics (A charger/inverter with batteries isolates the load from power quality, which could mean overall better protection but is not needed IF the generator is well maintained.
• inverter generators
  • use less fuel under less load but not as much less as the load is less Not at sure about whether this is all that different from the above case. More load needs more energy, regardless. the only real way to ensure constant load is to provide the generator with a constant load.
  • there's still a minimum load
  • the generator can spin down if there's less load so a lower load wont affect lifespan / service intervals
  • (You are burning fuel in both. So no I can't personally see this as an advantage
  • they are safe to connect to just about anything (provided the inverter is a pure sine wave inverter, which it should be on a quality generator.

Am I on the right track here?

Added some detail as I see it, Hope others' will add their thoughts.

 

[Geoff.D]

Yes, I was looking for those changeover switches. Saw them at an electrical supplier the other day. Really good idea, all in one sort out the neutral integrity problem. But, on the other hand, I "like" to be able to isolate power when working on anything.

 

[Obieone]

A carburetter jet. Of course all the millenials don't know what a carburetter is because no one has carburetter cars anymore.
And then we talk of progress!



If like us old timers you know a thing or two about carburetter engines you can fine tune the mixture without changing jets and adjusting the timing to ensure a perfect mixture and the least carbon build up.
You check this by looking at the exhaust of the engine. It should be running a grey colour not black (leaded petrol). If the exhaust is running black (leaded petrol), the mixture is too rich and or the load on the geni is not enough.

Edit/ As rightly pointed out in post #56 by @Düber, the exhasut colour is no longer an easy check for mixture as you don't get that nice grey colour with unleaded petrol. Now the check is to see if the spark plug is burning a nice brownish colour.

How do you do this? Will google in the mean time.

 

[Geoff.D]

How do you do this? Will google in the mean time.

Experience. How do you get that? You buy an old car (or an old landrover) or a beetle and practice. Lots of practice.
The landrover WILL give you plenty of opportunities to practice

 

[lestoran]

Added some detail as I see it, Hope others' will add their thoughts.

Appreciated

 

[Trust|Nobody]

So i've been reading a bit about generators (and load shedding solutions in general) both here and elsewhere but there's a lot of conflicting information out there.

To my understanding:

• non-inverter generators
  • use the same amount of fuel regardless of how much load is placed on it
  • there a minimum load that you must put on it
  • running too close to to the minimum too often means more servicing / shorter lifespan
  • without avr its not safe to connect to sensitive appliances
  • with avr power "quality" is close to inverter / eskom power
  • an inverter (with batteries) in front of a non-avr generator will clean up power so its safe to use with sensitive electronics
• inverter generators
  • use less fuel under less load but not as much less as the load is less
  • there's still a minimum load
  • the generator can spin down if there's less load so a lower load wont affect lifespan / service intervals
  • they are safe to connect to just about anything

Am I on the right track here?

This comparison is from Ryobi:



You missed the weight and noise categories.

 

[Trust|Nobody]

This comparison is from Ryobi:

View attachment 636506

You missed the weight and noise categories.

You can also pair inverter generators to double your power output but you can't do this with conventional generators.

 

[Trust|Nobody]

This guy has got a real easy solution for noisy generators:

Here are some comments

 

[Other Pineapple Smurf]

I must do a write up but if you think a single copper spike in the ground is going to help anyone in you case you are badly mistaken.

There is no earth leakage protection.

Infact a floating system without the earth spike will be safer if you don't have an earth leakage device. By adding the earth spike you are actually creating a path for fault current to flow ie if you touch the live conductor through your body into the earth back up through the earth spike completing the circuit back the alternator.


I'm not even sure if the neutral is bonded to the Frame on these generators - I'll check it out.

A long way to say don't stuff around get a professional to tie this into your DB with a change over switch.

And not a dude you pick up from the corner of builders warehouse

Electricity kills. Get an electrician who can issue a COC . Your insurance will ask for this should something go wrong and your house burns down.

Loadshedding is here to stay might as well get is done right now.

So are you trying to tell me that it is better to not earth my generator that has rubber wheels and rubber feet, not making any contact with the ground.

A generator that has an earth lug, trip switch and feeds appliances directly, not via the DB board?

 

[Obieone]

Experience. How do you get that? You buy an old car (or an old landrover) or a beetle and practice. Lots of practice.
The landrover WILL give you plenty of opportunities to practice

I know how to set timing and tune carbs on a car, I meant on a generator. Nevermind I'll google

 

[Geoff.D]

So are you trying to tell me that it is better to not earth my generator that has rubber wheels and rubber feet, not making any contact with the ground.

A generator that has an earth lug, trip switch and feeds appliances directly, not via the DB board?

There is a saying: No earth is better than a bad earth. In other words, a generator floating and feeding equipment that is NOT connected to any other earth is less risky.

What does the manual say? Is there a E/L breaker on the generator?

 

[Other Pineapple Smurf]

There is a saying: No earth is better than a bad earth. In other words, a generator floating and feeding equipment that is NOT connected to any other earth is less risky.

What does the manual say? Is there a E/L breaker on the generator?

Going through the manual there is no specific mention to an E/L breaker.

After the valid points made on this thread with regards to earthing, it made it easier to correctly understand what the manual actually says about earthing. Basically only when neutral wire of house is farther, this under the section of connecting to domestic circuits.

Thanks, will remove the earth wiring from the lug.

 

[Other Pineapple Smurf]

I guess this method was followed:

Obviously me explanation to what I did was not correctly worded. No, I did not attempt to qualify for the 2019 Darwin Award.

The leads and plug points are all in isolation to the rest of the house electrical circuit.