Author Topic: Noisy power from typical backup generators  (Read 9553 times)

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Offline Renate

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Re: Noisy power from typical backup generators
« Reply #25 on: February 24, 2021, 08:05:02 pm »
...when dealing with line voltages that can be a dangerous game.
True, but in an emergency (and especially with 3 phase) you wouldn't jumper the phases?
 

Offline IDEngineerTopic starter

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Re: Noisy power from typical backup generators
« Reply #26 on: February 24, 2021, 09:23:47 pm »
Actually, no. I don't think I would. Just not sufficiently confident that nobody would "do something" totally innocent, unaware of a wildly illegal and inadvisable wiring change like that. If the whole structure appears to be powered it's too easy for someone to forget, be innocently uninformed, to presume all is well, and do something even more hazardous. Line voltage is unforgiving.

I'd probably just devolve to running a few key things using extension cords straight from the generator(s). But this is why I focus on having a single 2-phase generator adequate to power the entire structure. Then everything works properly, as expected, and there are no "special rules" depending upon what power source you're using at the moment.

YMMV, others might choose differently, standard disclaimers, etc.
 

Offline EmptyHead

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Re: Noisy power from typical backup generators
« Reply #27 on: February 25, 2021, 06:34:18 am »
Quote
Incidentally, I did toy around with the idea of installing an electric start circuit to drive the PM alternator as a BLDC starter. I even got so far as to invest 16 quid in a 60v rated 300W electric scooter BLDC control unit with both Hall effect sensor and sensorless control options. I could get it to spin at about 480rpm using a 48v battery pack but only by removing the spark plug. Even blocking the spark plug hole with my finger whilst it was running was sufficient to stall it, proving that sensorless operation wasn't up to the task of handling such erratic mechanical loading.

I have a Honda EU2200i that I want to electric start so the lady can easily start with push of a button. Using the PM alternator as the starter motor is of particular interest. Any pointers you can share on this?
I would be interested in using a 12VDC lawn mower battery or Dewalt 20V max 9AH battery or Dewalt 60V 3AH battery(20v max 9ah)

First time post for me.
« Last Edit: February 25, 2021, 06:39:19 am by EmptyHead »
 

Offline james_s

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Re: Noisy power from typical backup generators
« Reply #28 on: February 25, 2021, 08:52:47 am »
Sure you can. Just jumper the phases in the main panel.
Wait, what? Surely you don't mean paralleling (jumpering) both phases so they act as a single phase?!? How would that work for 240VAC loads? At best they'd see a net 0VAC across their inputs.

It works just fine for 120V loads, I've done it for years, a friend of mine has done it for years. I don't have any 240V loads on the portion of my panel that is on the transfer breaker and neither does he but it wouldn't cause any problems, they'd just get 0V just as you'd expect. The little 2kW generators we have are not powerful enough to run the loads that require 240V anyway. They don't have to be, it would be silly for me to buy a gigantic generator that burns several times as much fuel just so I can run my clothes dryer or air compressor while the power is out. It's a backup generator, it's for emergency use. I fail to see how it is dangerous to feed both legs of the panel from the same wire. There's a physical interlock on the breakers so the generator breaker cannot be turned on while the utility main is on, and the bridge is in the socket on the end of the cord that goes from the generator to the house. I've been very happy with my setup and don't view it as a hack at all. A lot of people run extension cords all over their house to power lights and appliances in an emergency, *that* is a hack. I plug in my cord, fire up the little Honda, and then go in side and shut off the main, slide the interlock up and turn on the generator breaker and all of my lights and 120V loads are powered. I have an alarm that detects when utility power has returned so I can go shut down the generator and switch it back over so I'm not that guy who leaves the generator running for an hour after the power has come back.

Look at the fuel consumption, a 3kW generator uses quite a lot more fuel delivering say 500W than a 2kW generator does supplying the same load. A 7kW generator will use a LOT more fuel powering that same load, not to mention it will be much heavier and take up a lot more space. If you need the power then buy a generator that can meet your needs, but for those who can get by with less the little 2kW suitcase units are fantastic, mine lives in a closet in the utility room when not in use and when I need it I can carry it in one hand. At light load it will putter along for around 12 hours on a single gallon of gas. It's small enough that I can set it in my car and use it for camping or running power tools in a remote location. My neighbor's gigantic 8kW generator slurps down more like 6 gallons of fuel in that same time, makes so much noise that I can barely tell mine is running standing a few feet away from it over the din of his across the street and his is so bulky and heavy it has to be rolled around on wheels. No thanks.
 

Offline Renate

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Re: Noisy power from typical backup generators
« Reply #29 on: February 25, 2021, 12:00:20 pm »
Ah, camping, back to nature, peace and quiet.
For some Americans that apparently has no appeal.
No, this photo is not from a rock concert only a little camping site.
« Last Edit: February 25, 2021, 03:11:23 pm by Renate »
 

Offline richard.cs

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Re: Noisy power from typical backup generators
« Reply #30 on: February 25, 2021, 01:49:36 pm »
I don't have any 240V loads on the portion of my panel that is on the transfer breaker and neither does he but it wouldn't cause any problems, they'd just get 0V just as you'd expect. ... I fail to see how it is dangerous to feed both legs of the panel from the same wire. There's a physical interlock on the breakers so the generator breaker cannot be turned on while the utility main is on, and the bridge is in the socket on the end of the cord that goes from the generator to the house.
I don't see the issue here either, the jumper is on the interlocked side so you never get the situation of the grid seeing a line-line short. 240V loads getting 0V isn't dangerous, so what's not to like?*

<UK>*Well, apart from the use of 120 V and the whole split phase system itself.  ;D </UK>
 

Offline james_s

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Re: Noisy power from typical backup generators
« Reply #31 on: February 25, 2021, 09:54:08 pm »
Ah, camping, back to nature, peace and quiet.
For some Americans that apparently has no appeal.
No, this photo is not from a rock concert only a little camping site.

There are different kinds of camping. I don't typically take a generator along but it can be handy to have for longer trips at campgrounds that lack amenities, especially if there's a trailer that has an air conditioner or even just a couple of fans and you're in a hot place in the summer, those turn into an oven during the day and it's handy to be able to charge up batteries or run various devices. I wouldn't bring it for a weekend of tent camping in the woods, some people are a bit ridiculous about such things but thankfully most of those sort of campgrounds don't allow generators.
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #32 on: February 27, 2021, 09:55:01 pm »
Quote
Incidentally, I did toy around with the idea of installing an electric start circuit to drive the PM alternator as a BLDC starter. I even got so far as to invest 16 quid in a 60v rated 300W electric scooter BLDC control unit with both Hall effect sensor and sensorless control options. I could get it to spin at about 480rpm using a 48v battery pack but only by removing the spark plug. Even blocking the spark plug hole with my finger whilst it was running was sufficient to stall it, proving that sensorless operation wasn't up to the task of handling such erratic mechanical loading.

I have a Honda EU2200i that I want to electric start so the lady can easily start with push of a button. Using the PM alternator as the starter motor is of particular interest. Any pointers you can share on this?
I would be interested in using a 12VDC lawn mower battery or Dewalt 20V max 9AH battery or Dewalt 60V 3AH battery(20v max 9ah)

First time post for me.

 One of my reasons for investigating the possible use of the alternator as a BLDC starter motor was because the inverter module just happened to completely block easy access to the hex nut that typically retains the flywheel and cooling fan onto the end of the crankshaft, preventing the use of the classic "cordless drill with hex socket and extension" starter trick.

 Believe me, If it had been possible to use the cordless drill trick, my electric starter project would have been nothing more than an interesting "Thought Experiment. I'm nothing if not pragmatic about seeking an improvement over that accursed pull start with a recoiling rope bodge that some dope back in the last century thought would be good enough for small outboard motors and which, sadly for us all, was adopted as "An Excellent (dirt cheap to implement)" starter method on almost every small ICE powered gadget from chain saws to weed whackers and moderately sized gensets. The electric (cordless) drill trick would have served me just fine, thank you very much!

 If you're lucky with that EU2200i in being able to access the crankshaft nut by drilling a strategically placed hole in the case by which to insert a suitable hex socket on an extension adaptor, that might be all that's needed to take the strain out of starting on the pull cord by your good lady. Mind you, there's some small skill required to disengaging the "starter" in a timely fashion and the direction of rotation as seen from that end of the crankshaft should ideally be clockwise to minimise the risk of accidentally undoing the fan/flywheel retaining nut (although I think I may overstating the risk - best ask others experienced in the black art of electric drill starting for their considered opinion on this).

 Inverter gensets designed for 120vac output generate only half the voltage used by UK and EU "230" volt inverter gensets making such modification a little easier to implement. This gives you more voltage margin when adapting a cheap 20 dollar 300W rated electric scooter BLDC controller module designed for battery pack voltages only as high as 60v since you only need to power it from a 24 to 30 volt starter "battery voltage".

 The time you have in which to isolate the module between first power stroke and the revs accelerating to a dangerous voltage output speed is much greater since not only is the slope of this voltage increase gentler, you also have a larger difference between the 24/30 volt and the engine speed point at which the 'back EMF' becomes too high for the module's output transistors to handle without damage.

 It just might be possible to replace the existing output transistors (usually power FETs in these modules) with higher voltage rated devices (600v in my case or 300v with a 120vac output inverter genset) to proof it against the normal alternator output voltage without the complication of an add on relay isolating circuit. However, this does depend on how the High Side drive voltage circuitry is implemented so making a cheap commodity 60v rated BLDC controller HT proof will likely be a little more complicated than merely swapping out the half dozen 80v rated power FETs for 300 or 600 volt rated ones.

 For a given 1KW rating, one would expect the stator windings resistance of a 240v inverter generator to be four times greater than that of its 120v counterpart. When I was testing this out some 18 months or so back, ISTR stator resistance values of 7 or 8 ohms with an unloaded (spark plug removed) current draw from my 48v battery pack of just under half an amp at 480rpm.

 I calculated a starting from standstill current draw of 4 amps peak and a half unloaded (cranking) speed to demand a little over two amps. In the case of a 120v 1KW inverter genset, you can expect at least a doubling of these amperage figures using a 24 battery and likely another 50% more for a 2KW rated genset.

 I did check out drive modules designed for VFD use with 600v rated output devices but it wasn't certain whether they could still function reliably (or at all) off a 48v supply (they'd normally be powered from rectified and smoothed mains voltage, 350vdc from 240vac or 170vdc from 120vac supplies) so I didn't pursue this avenue of research any further since these drive modules weren't cheap.

 Anyway, that's the stage I reached before I lost interest over 18 months ago. As I said previously, I might take another look at cracking the sensored commutation problem come the warmer summertime weather conditions. I had hoped initially that my electric start upgrade could avoid any mechanical modifications to the engine/generator assembly itself but it looks like I'm going to have to at least remove the fan cowling to access the flywheel to test the viability of using hall effect sensors to detect flux leakage from the embedded magnets which is more of a strip down than I've so far attempted.

 Since I'll need to strip the outer covers off anyway before I can look to getting access to the flywheel, I'll take another look at the possibility of shifting the inverter module to allow cordless drill access to the crankshaft flywheel/fan retaining nut. I may have given up too easily the first time round on this approach to the problem of starting it electrically. It's been over 18 months since I last saw the internal arrangement - perhaps with enough determination, I might find a way to relocate the inverter module to allow the use of a cordless drill for starting it up. Sometimes the simplest solutions turn out to be the most optimal in the end. ::) :popcorn:

John
John
 
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Offline IDEngineerTopic starter

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Re: Noisy power from typical backup generators
« Reply #33 on: February 27, 2021, 10:10:37 pm »
That's a lot of work to avoid pulling on a rope. Not that I don't appreciate a good DIY project.

Might be simpler to start it with a shot of compressed air.

There's also a starting system, by Honda(!) I believe, in which you precharge a spring with multiple gentle pulls on the rope. Then a button uses the spring to aggressively dump the energy into the crankshaft for starting. Essentially mechanical leverage with a delay, via energy storage, in the middle.

As for decoupling your starter system once the engine starts and spins up, that's exactly what a Bendix system on a starter does. Those usually extend and retract to engage a gear on the edge of the flywheel, but seems like you could install a coupling on the end of that same shaft to first engage the crankshaft to start the engine, and then retract once the engine overrevs the Bendix mechanism. In other words, install them in line and engage axially instead of radially.

Just some random thoughts, worth exactly what you paid for them! {grin}
 

Offline james_s

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Re: Noisy power from typical backup generators
« Reply #34 on: February 27, 2021, 10:11:09 pm »
Well the EU2000i definitely uses a 3 phase permanent magnet alternator so it shouldn't be too hard to spin it with a BLDC controller. You don't need anywhere near the power level it is designed to generate in order to turn over the engine for starting so you might get away with a considerably lower voltage. Normally I think electric start is a pointless gimmick that adds considerable cost, bulk and weight and I actually quite like the elegant simplicity of a recoil starter, no battery to haul around or keep charged, no separate starting accessory to keep track of, just pull the self contained cord and it starts. In the case of a generator that already has most of the hardware present it makes a lot more sense though, just add a battery and a few extra parts and firmware on the inverter board. Hybrid cars have been using combined alternator/BLDC starter units for years.
 

Offline EmptyHead

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Re: Noisy power from typical backup generators
« Reply #35 on: February 27, 2021, 10:41:03 pm »
Johnny B Good
Thanks for the info. You've answered my questions. I think that's enough to help me decide it's a viable project.
Honda EU2200 3Q winding- 1.0 to 1.8 ohm acceptable resistance(according to Honda spec sheet)
During testing I've seen peak voltage of 286VAC L-L

Connecting a drill as a starter is something I do for other lawn & garden equipment but I've decided not to do that on EU2200 because it would require:
1. Removing/eliminating existing recoil start
2. Modifying flywheel mounted fan and mounting setup
3. Totally relocating the inverter
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #36 on: February 28, 2021, 01:11:06 am »
Johnny B Good
Thanks for the info. You've answered my questions. I think that's enough to help me decide it's a viable project.
Honda EU2200 3Q winding- 1.0 to 1.8 ohm acceptable resistance(according to Honda spec sheet)
During testing I've seen peak voltage of 286VAC L-L

Connecting a drill as a starter is something I do for other lawn & garden equipment but I've decided not to do that on EU2200 because it would require:
1. Removing/eliminating existing recoil start
2. Modifying flywheel mounted fan and mounting setup
3. Totally relocating the inverter

 AFAICR, the recoil starter mechanism is between the flywheel and the engine (BICBVW). I'll worry about that once I've pulled the casings off when the weather improves.

 Point two: I may face a similar situation but if there is a hexagonal bolt holding the flywheel/fan onto the end of the shaft, I may be able to use the electric drill trick, provided I can deal with point three which our Honda and Parkside inverter gensets have in common.

 I can understand your interest in adding an electronics pack to press the alternator into doubling up as a starter (a modern day version of the dynastart setup used by some small 2 cylinder marine engines in the previous century).

 For a DIY project, the cheap electric bike BLDC controller with isolating relays looks the most promising cost effective way to endow these inverter gensets with an electric start feature (provided some sort of hall effect sensor can be cobbled up - sensorless, fine as it is with propellor motors used by drones and RC controlled fixed and rotary wing models just doesn't work in this case).

John
John
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #37 on: February 28, 2021, 01:28:14 am »
Well the EU2000i definitely uses a 3 phase permanent magnet alternator so it shouldn't be too hard to spin it with a BLDC controller. You don't need anywhere near the power level it is designed to generate in order to turn over the engine for starting so you might get away with a considerably lower voltage. Normally I think electric start is a pointless gimmick that adds considerable cost, bulk and weight and I actually quite like the elegant simplicity of a recoil starter, no battery to haul around or keep charged, no separate starting accessory to keep track of, just pull the self contained cord and it starts. In the case of a generator that already has most of the hardware present it makes a lot more sense though, just add a battery and a few extra parts and firmware on the inverter board. Hybrid cars have been using combined alternator/BLDC starter units for years.

 You've echoed my own thoughts regarding the idea of making the alternator double up as a starter for the want of a few extra components in the inverter module, requiring only the weight penalty of a battery which could even be a lightweight LiPo battery pack rather than a rather heavy 7 or 12 AH 12v SLA.

 John


 
John
 

Offline james_s

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Re: Noisy power from typical backup generators
« Reply #38 on: February 28, 2021, 01:30:49 am »
Well the service manual is readily available online so you can easily see how it all fits together. I would certainly not want to make any modifications that impair the recoil starter, as you wouldn't want to be unable to start your generator while the power is out due to forgetting to keep your cordless drill charged.

I find the little EU2000i to be easy to start with the recoil though, it's just a tiny little engine. Larger units require more strength and could more greatly benefit from electric starting, many of them already have it. There are also open frame inverter generators that are not only cheaper than the enclosed super portable suitcase models but the internal components are more accessible.
 

Offline EmptyHead

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Re: Noisy power from typical backup generators
« Reply #39 on: February 28, 2021, 01:46:51 am »
Quote
For a DIY project, the cheap electric bike BLDC controller with isolating relays looks the most promising cost effective way to endow these inverter gensets with an electric start feature (provided some sort of hall effect sensor can be cobbled up - sensorless, fine as it is with propellor motors used by drones and RC controlled fixed and rotary wing models just doesn't work in this case).

I'm not an expert on BLDC controllers but I suspect EU2200 will require over 100V into stator for cranking speed and power. I hope that sensorless will work.
The 286VAC I mentioned earlier was in the most extreme case I could come up with - loaded to 3000W resistive load and disconnecting full load - it would overspeed to about 5800RPM and found peak voltage.

Toyota Prius starter/generator combo and 30 year old golf carts is what made me think of this - internet searches lead me to your post.


The EU2200 service manual is difficult to find online.
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #40 on: February 28, 2021, 04:11:40 am »
@IDEngineer

 I don't think the compressed air technique would work with a single cylinder 4 stroke ICE. It might be ok with a twin cylinder two stroke engine. I know compressed air starting is commonly used in large marine diesel engines but they generally have 4 or more cylinders to work with. However, since I've no experience with such compressed air starting and even less knowledge about the details involved, I could be wrong. It's just a gut feeling I have that you need more than just one cylinder for compressed air starting to function reliably.

 TBH, I started losing motivation to continue my DIY electric start once I'd figured out a less painful technique to prime the carb float bowl by cranking not so energetically on the pull starter with the ignition off for about four pulls before finding the top of the next compression stroke and taking it just 'over the hump'  before turning the kill switch to the run position and giving the starter cord a very firm yank with a very high probability that it will fire up "First go" rather than snatch back.

 My problem had simply been a lack of finesse, wasting energy in priming the carb leaving me too little energy left to crank it fast enough to avoid the kickback risk by the time it was finally ready to start. A fuel lift pump priming lever would have made life so much easier for both me and the service life of the starter cord. Still, for just £99,95, I suppose I should be grateful they'd even equipped it with a recoiling starter cord. :-DD

 The comparison to the bendix mechanism's function did come to mind, along with the free wheeling starter pinion clutched onto the crankshaft of the Honda CB160's twin cylinder engine using a cunning spring loaded three ball bearings mechanism to provide the free wheeling function which worked surprisingly well as an alternative to a bendix or a pre-engaged starter setup.

 I'm considering the possible use of a small starter motor transmitting its drive via a rubber faced wheel pressing against the flywheel rim. At its simplest, it could just be a lever operated swivelling of the starter on a hinged bracket against the flywheel, the pressure of which would also force a contactor closed to switch the starter motor on.

 The charm of this being that no starter ring is required on the flywheel making it applicable in principle to almost any small inverter gensets that otherwise don't have a manufacturer supplied electric starter kit option. An alternative to swivelling the whole starter motor would be to use a rubber faced idler wheel that can be pressed (or pulled) into contact with the starter drive shaft and the rim of the flywheel.

 Of course, this assumes there won't be any insurmountable problems securely attaching the mechanism onto the engine itself. At this time, this is an imponderable requiring careful examination of my options once I have the case covers off to actually see what mounting options there might be, if any.  This just a bit of a brainstorming on my part which will probably all amount to nothing in the end. |O

John
John
 

Offline james_s

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Re: Noisy power from typical backup generators
« Reply #41 on: February 28, 2021, 05:11:40 am »
TBH, I started losing motivation to continue my DIY electric start once I'd figured out a less painful technique to prime the carb float bowl by cranking not so energetically on the pull starter with the ignition off for about four pulls before finding the top of the next compression stroke and taking it just 'over the hump'  before turning the kill switch to the run position and giving the starter cord a very firm yank with a very high probability that it will fire up "First go" rather than snatch back.

 My problem had simply been a lack of finesse, wasting energy in priming the carb leaving me too little energy left to crank it fast enough to avoid the kickback risk by the time it was finally ready to start. A fuel lift pump priming lever would have made life so much easier for both me and the service life of the starter cord. Still, for just £99,95, I suppose I should be grateful they'd even equipped it with a recoiling starter cord. :-DD

Mine usually starts on the first or second pull, no aggressive yanking, no particular technique, I just turn on the fuel/ignition switch, set the choke, grasp the cord and give it a brisk yank as soon as I feel the pawl engage. The little Honda engines are fussy about fuel though, I always use fresh fuel, non-ethanol and put stabilizer in it. Unless I think I'll be using it again shortly I drain the carb bowl before I put it away, it has a drain tube you can stick in a cup, open the drain screw and then pour that fuel back into the tank if you want. The carb jet is very small and easily clogged, if yours is hard to start try cleaning out the carburetor and use some fresh fuel. If you can't find a place to get non-ethanol pump fuel you can buy those cans of engineered fuel. They're to expensive for day to day use but it's fine for occasional needs.

I remember my dad telling me that the Honda outboard motor he had on a dinghy didn't like stale fuel either, and I have a Honda powered pressure washer that is also very hard to start on old fuel. I don't know why they're so fussy but they run very well and are efficient as long as you have good fresh stuff in the tank.
 

Offline Renate

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Re: Noisy power from typical backup generators
« Reply #42 on: February 28, 2021, 11:41:09 am »
Yeah, getting fuel into the carb before cranking would be nice.
I have an Onan 2.8 kW (that I don't use much).
The first few seconds of cranking (after long disuse) are wasted.
I would add a switch to prime the electric fuel pump but I'll have to wait until the next time I drop it.
A friend has already added a switch to theirs.
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #43 on: February 28, 2021, 08:26:59 pm »
 The problem I have is the need to spin the engine over to operate the fuel lift pump to refill the carburettor float bowl. The Parkside unit has the same drain screw and plastic drain pipe which simply exits out the bottom of the generator but it's a feature I don't need to use since I can simply shut the fuel off and let it run dry before putting it into storage. That's the (vital in this case) advantage of NOT combining the fuel tap with the ignition kill switch. Keeping those two functions completely separate neatly avoids any need to wear out a carb drain screw - just shut off the fuel after disconnecting the load and then wait the next 2 or 3 minutes it takes to run the float chamber dry. :)

 I wouldn't have this problem if Parkside had thought to provide a fuel lift pump priming lever or 'bulb' to pneumatically operate the pump to refill the carburettor float bowl without having to apply 4 or 5 gentle 'dummy run' pulls on the starting cord. >:( :(

 I suppose I should fit a fuel lift pump replacement that supports such manual priming to save the needless wear and tear on the starter cord and preserve my energy for a successful first time, every time pull on the starting cord. Such a feature would have put all thoughts of trying to upgrade to an electric starting system completely out of my mind. I think it's high time I did some research into this business of manually operating a fuel lift pump.

 I might discover that adding a "Priming Bulb" is simply a matter of teeing in a small bore rubber hose from a squeeze bulb into the engine (inlet port vacuum or crankcase pressure?) line which operates the pump.

 Apparently, after a duckduckgo search for the information I so craved on this subject (not quite the usual hunt for hen's teeth and Unicorn droppings this time), I discovered that such priming bulb setups aren't nearly as sophisticated as I expected. Indeed, after viewing a few youtube chainsaw repair videos on the subject, it's even more mind numbingly crude than I'd ever imagined.

 From what I saw, it seems all that's really needed is a priming bulb kit with a metre's worth of fuel line and a couple of T pieces to effectively put the priming bulb in parallel with the existing fuel lift pump. It seems to me that such an arrangement won't interfere with the fuel lift pump unless the priming bulb goes faulty hence my ordering a pair of 3mm plastic Tpieces (£2.28 delivered) and a "Fuel Lines with Fuel Filter & Primer Bulb for Tygon Craftsman Poulan Chainsaw" kit with two priming bulb pumps (£4.91 delivered) from UK based ebay sellers.

 Fingers crossed that I've ordered the right size of T adaptors to match the Parkside fuel line and one of the two 900mm lengths (2.0 and 2.5 mm ID) supplied with the kit. The £7.19 investment is a modest price to pay for  easier starting. It should be just as effective as the four or five 'priming pulls' on the starter cord but without all the wear and tear on the cord and my well-being.

 I may have the fuel priming kit installed in a week or two's time. I'll let you know the result once I've had a chance to test it out.

John
« Last Edit: February 28, 2021, 08:36:15 pm by Johnny B Good »
John
 

Offline G7PSK

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Re: Noisy power from typical backup generators
« Reply #44 on: March 01, 2021, 04:05:13 pm »
I have built a number of alternator sets over the years mostly using stamford brand of alternator, now part of cummings power, I never had any trouble with noisey power from them and they use electronic AVR's or transformer type regulation on the smaller units. All the rotors have had a slight helical form to the windings which i understand helps with delivering a smoother waveform.
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #45 on: March 03, 2021, 12:34:52 am »
I have built a number of alternator sets over the years mostly using stamford brand of alternator, now part of cummings power, I never had any trouble with noisey power from them and they use electronic AVR's or transformer type regulation on the smaller units. All the rotors have had a slight helical form to the windings which i understand helps with delivering a smoother waveform.

 Have you ever tested the effect of connecting a 4.7uF PFC capacitor across the output? You might be shocked by the result. These generators can handle resistive and inductive loads ok but can end up overvolting due to the self excitation effect caused by the leading current produced by a capacitive load which in my case was the 9.4uF's worth of capacitance across the mains input of a SmartUPS2000 line interactive UPS which would be disconnected when it transferred  to battery power due to the incoming generator voltage going north of the 240v mark by some 30 volts or more.

 I couldn't figure whether these caps could be safely disconnected or not and their exact function remains a mystery. It's possible that modern line interactive UPSes may have eliminated the need for such a large amount of capacitance on their mains input circuit (that SmartUPS is well over a quarter of a century old now) so you might not see the overvolting issue I'd suffered with my own setup if you're feeding the generator's output into the mains in socket on a modern UPS.

 As for my own thoughts on how to add a fuel priming bulb to that Parkside inverter genset, it has occurred to me that I could have saved on the T adapters and just plumbed it into the fuel line (before or after the pulse driven lift pump), assuming the one way valves don't create an excessive pressure drop. I'll test the simple series arrangement first but my original parallel arrangement might well prove to be the only viable alternative to the more usual arrangements.

 Such arrangements being that it's plumbed into an extra hose nipple on the carb to let it suck the fuel through to prime it and send the excess back to the tank or else simply to squirt extra fuel into the inlet port to make up for a dry bowl and make it easier to start.

 It seems I've come up with a third alternative that's never been mentioned in any of the youtube videos I've watched (the only source I could track down that offered even so much as a clue as to how these pulse driven fuel lift and priming bulb pumps work) in relation to priming such small engine kit relying on a (crank case pressure) pulse driven fuel lift pump. I'll report my results here in a week or two's time after I've had a chance to work on the generator.

John
« Last Edit: March 03, 2021, 12:41:49 am by Johnny B Good »
John
 

Offline IDEngineerTopic starter

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Re: Noisy power from typical backup generators
« Reply #46 on: March 03, 2021, 12:44:01 am »
I couldn't figure whether these caps could be safely disconnected or not and their exact function remains a mystery... that SmartUPS is well over a quarter of a century old now
APC once made decent UPS's, but by the time we started using SmartUPS in the late 90's and early 00's they were already in decline. Their battery charging circuits were terrible - AFAIK just raw current dumped into the AGM batteries, causing them to swell within a year. I've lost count of the number of SmartUPS I had to mechanically disassemble just to remove the swollen batteries and replace them with new ones, which would themselves inevitably swell within 12 months. BTW, disassembling their 4U SmartUPS was its own precious nightmare with all sorts of interlocking walls to save a screw or two.

Given their simply awful battery charging, I wouldn't put too much faith in their AC output design (and their inclusion of those caps you're talking about).
 

Offline NiHaoMike

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Re: Noisy power from typical backup generators
« Reply #47 on: March 03, 2021, 03:19:32 am »
Have you ever tested the effect of connecting a 4.7uF PFC capacitor across the output? You might be shocked by the result. These generators can handle resistive and inductive loads ok but can end up overvolting due to the self excitation effect caused by the leading current produced by a capacitive load which in my case was the 9.4uF's worth of capacitance across the mains input of a SmartUPS2000 line interactive UPS which would be disconnected when it transferred  to battery power due to the incoming generator voltage going north of the 240v mark by some 30 volts or more.
I wonder if that effect could be put to good use by allowing the generator to run a little slower while still delivering the correct voltage thus saving fuel if the full output rating is not required.
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Offline james_s

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Re: Noisy power from typical backup generators
« Reply #48 on: March 03, 2021, 06:38:11 am »
I wonder if that effect could be put to good use by allowing the generator to run a little slower while still delivering the correct voltage thus saving fuel if the full output rating is not required.

Generators with AVC can easily be slowed down some and maintain voltage, but in a non-inverter generator frequency output is directly tied to engine RPM. Slowing it down will cause motors to run slower, transformers may saturate and some lights will flicker.
 

Offline Johnny B Good

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Re: Noisy power from typical backup generators
« Reply #49 on: March 03, 2021, 04:08:43 pm »
@IDEngineer,

 It took a few years before the penny dropped that the13.8v float charging voltage per 12v SLA wasn't the optimum voltage level to maintain SLAs at a relentless 365 days a year for years at a time (at least as far as end users were concerned). It undoubtedly was for APC and other manufacturers in that it allowed the use of undersized and expensive SLA battery packs by maximising the energy storage capacity when brand new and for the first year (or two at most) of their service life before going into a decline over the next year or three if you were very lucky or waited until they eventually failed the UPS's weekly battery test cycle.

 I'd bought that SmartUPS2000 sans battery box at the Blackpool radioham rally some 15 to 20 years ago (the exact date is now lost in the mists of time) which allowed me the freedom to choose whatever capacity of battery I could afford to buy.

 I think I started off with a set of four 7AH SLAs supplementing them with a set of 25AH SLAs purchased the following year at the next rally. At some point, I'd managed to cut a deal with a local car parts/salvage dealer for a set of four NOS 36AH SLIs to build the battery capacity to a grand total of 75AH (based on an unwarranted assumption that the two banks of 7AH and the one bank of 25AH, along with those four SLIs I'd managed to blag for a mere 60 quid still had their specified capacity). A test run with some 300W of loading resulted in almost 6 hours of autonomy before the voltage dropped to the cut out point at 40.4v.

 The SLAs survived this 13.8v abuse for maybe a couple of years of service but the SLIs only lasted a mere 6 months which was to me a surprising result considering the much easier life compared to their normal use as SLI batteries. It took another set of 36AH SLIs and remembering the similarly short life of a 40AH SLI I'd used with a CB radio powerpack to increase the peak current output back in the late 80s / early 90s before I realised that SLIs were simply unsuited to this task.

 By the time I'd realised the high battery maintenance costs, even when I was paying only a fraction of the full retail price, I'd already gone through two sets of SLIs, one set of 25AH SLAs and a box of sixteen NOS 7AH SLAs I'd purchased very cheaply from my son's best friend plus the first two sets I'd started off with. Mind you, I'd used at least two of the 7AH batteries to replenish the pack in that SmartUPS700 I've given the sack to and at least half a dozen used by the UPSonic 600 (likewise long since retired) which burned through them three or six at a time (36v in one or two banks).

 At one point, I had a total of five UPSes in service burning a total of 72W in maintainance consumption (32W for the SmartUPS2000, 20W for the SmartUPS700, 18W for the UPSonic600, 7W on an ancient Emerson30 (my very first UPS which was a modified sinewave type) plus maybe another 8 W on a now forgetable UPS I managed to burn out by connecting it to an external 25AH 24v battery to replace its knackered internal 4.5AH SLAs. This was replaced with an APC BackUPS500 (which uses just a single 7AH SLA) about ten years ago.

 As a result of my experience and research, I've now dropped the per 12v battery float charge voltage down to 13.5v[1] on the two remaining UPSes (SmartUPS2000 and the BackUPS500 which uses just under 3W of maintainance for its 350W/500VA's worth of protection) and stopped wasting money on cheap NOS car batteries. I'd made this decision some three or four years ago when I'd had to replace the single 7AH SLA in the BackUPS500 around the time I gave up satisfying the SmartUPS2000's appetite for eating battery packs by removing it from service as a 'protected supply'. It was only due to the purchase of the Parkside inverter genset that motivated me to invest in a set of four 7AH SLAs so I could verify my hypothesis that an inverter genset would solve the problems I'd experienced with a conventional 2.8KVA PowerCraft generator a few years earlier.

 The SmartUPS2000 original battery pack is specified to be 18AH so the set of four 7AH SLAs won't offer much autonomy, just enough to run the inverter genset test and provide 5 or 10 minutes on the current 300W load. Recently, I discovered the charm of LFP battery technology which blows away the ancient SLA in regard of every aspect (2000 and more charge/discharge cycle ratings for a 20% loss of capacity when cycled to an 80% DoD and a much flatter discharge voltage curve - improved WH capacity and round trip efficiency compared to even a lightly stressed SLA battery pack limited to 50% or less DoD).

 The only thing not to like is their capital cost. If you purchase from any of the UK suppliers, you can land up paying two to three times what you can buy them for when using the likes of Alibaba to purchase them directly from the manufacturers in China.

 Four LFP cells in series conveniently creates a 12.8v battery replacement for the classic 12.6v SLA. You just have to size them so their 1C discharge rating matches the peak current demand by the UPS. In my case, I'd need to build a 16s 50AH battery pack for my SmartUPS2000 which, at UK prices, would be an 800 quid or more investment plus carriage charges. Even at 400 quid delivered from the Chinese manufacturer via the auspices of Alibaba, it's still a large investment although it works out at less than the price of two sets of APC branded 18AH battery packs which, rather obscenely imo, are regarded as a 'consumable' :wtf: Who the hell stood still for this particular scam? ::)

 The LFP battery makes for a one time only capital investment that's likely to outlive the UPS, totally turning the concept of the battery being a 'consumable' versus the one time investment in the UPS itself which now becomes 'the consumable'. An LFP battery pack replacement is more than worthy of consideration. I'll be investigating the pros and cons of ordering a set via Alibaba. So far it's mostly pro and little to no con but I'm not quite ready to pull the trigger on placing an order for a 16 cell 50AH LFP battery pack just yet. :popcorn:

[Note 1] This was a decision backed up by the fact that a secondhand 12AH SLA I'd purchased at our local flea market (which turned out to be 11.95v rather than the 12.5v reading on a borrowed DMM I'd used to assess whether it would be worth its asking price) for just a fiver over five years ago now, had only ever been charged from a pair of 1.2Wpk output solar panels hung outside of the office window for a week or so each summer and then left to rest until the following summer's annual refreshing charge for the first five years of ownership and showing a resting voltage that never dropped below the 12.7v mark.

 I use it on infrequent occasions as a test battery. One time I even used it to jump start a 1.6litre automatic with a totally knackered battery that had left me stranded outside of our local chippy one winter's night. What this had demonstrated was that a quality made SLA did not need to be cossetted with a battery conditioning charger to avoid the overhyped sulphation risk. It seemed to me that if the resting voltage could be kept above the 12.7 volt mark, this was sufficient to protect against the sulphation risk, suggesting that an unremitting 13.8V float charge voltage was way more than was good.

 The reduced float charging voltage may knock some 5 to 10 percent off the usable capacity but the elimination of the corrosive wear and tear from float charging an SLA at 2.3v per cell makes such a small sacrifice of performance more than worthwhile.

John
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