192 replies to this topic
Posted 2009-11-21 05:27:08
Observer: " Most synchronous generators are designed to support 300% of their rated kVA for 10 seconds. From the OP, [(600 amps starting current)(230 volts single phase)]/1000 = 138 starting kVA"
Genset:"a generator with the correct insulation class (H), may also handle high overcurrent for short periods (such as that mentioned in Naams question), but the potential for alternator insulation failure is high', I followed this up more recently with the comment that things just arent made the way they used to be..."
Gentlemen, assuming both claims are valid it is beyond my comprehension that the supplier of generators (main parts engine and alternator) would try to save cost by being stingy as far as insulation class of the alternator wiring is concerned. in Nigeria i bought the generator together with his twin second hand from a german construction company which withdrew from the country. that was end of 1981, both units were most probably 2-3 years old. and now i am told that after THIRTY years of technical and manufacturing development the products are inferior? 
Posted 2009-11-21 05:47:50
And Naam,here is your drawing of the switching using a manual rotary changeover switch. 1-0-2.
Posted 2009-11-21 06:08:10
 Naam, on 2009-11-21 05:27:08, said:
Observer: " Most synchronous generators are designed to support 300% of their rated kVA for 10 seconds. From the OP, [(600 amps starting current)(230 volts single phase)]/1000 = 138 starting kVA"
Genset:"a generator with the correct insulation class (H), may also handle high overcurrent for short periods (such as that mentioned in Naams question), but the potential for alternator insulation failure is high', I followed this up more recently with the comment that things just arent made the way they used to be..."
Gentlemen, assuming both claims are valid it is beyond my comprehension that the supplier of generators (main parts engine and alternator) would try to save cost by being stingy as far as insulation class of the alternator wiring is concerned. in Nigeria i bought the generator together with his twin second hand from a german construction company which withdrew from the country. that was end of 1981, both units were most probably 2-3 years old. and now i am told that after THIRTY years of technical and manufacturing development the products are inferior?
Naam,
No, contemporary alternators are not inferior, far from it, but 300% of rated Kva for 10 seconds equates to an enormous amount of heat being generated in the alternator windings. These recommendations exist to extend the life of an alternator at the end of the day Naam... the manufacturer doesnt want you to burn your alternator out through misuse.
Having said that, competition is rife and the bottom line does lead to cost cutting in some areas which irritate me to be honest. Mecc Alte exciter coils is one such gripe... they need to spend a little more money on improving the insulation of their exciter coils in my opinion, far too many of them short out in only moderate damp conditons and can be a real pain to change sometimes. I have taken to disassembling every Mecc Alte alternator that I fit and spraying additional insualtion on the exciter coil to reduce the frequency of these specific faults.
Let me qualify the remark I made, if I may... I regularly see alternators (belt driven PTO Tractor sets mostly), which are thirty + years old. These belong to old farmers who work the things hard, constantly (and dont like to spend money...!). I see them when the belts need changing, these things are overwound and heavily insulated, I have no doubt that they will be providing power to the milking parlours of future farming generations for years to come... 'They just dont build them like they used to...' (is the term I should have used), is a reference to the fact that these generators take a lot of stick and last for years because they were overbuilt and not because they were technically superior.
Genset.
Edited by genset, 2009-11-23 07:09:20.
Posted 2009-11-22 23:58:32
Quote The neutral conductor is not switched.
You can make a working drawing from this information
Hi David96,
You went on to add, (a note at the end of the drawing you subsequently posted), that;
Quote 'main neutral and generator neutral are connected to the neutral bar of the switchboard directly, they are not switched'
With respect, I disagree with you on the issue of a permanent neutral connection to a secondary power source (generator) for domestic use.
It is my preference to always treat a standby generator for domestic use (and not designed to sync and run parallel with the utility supply), as a separately derived source of power. As such the star point of the alternator is connected to earth via a grounding electrode at the site of installation and the alternator neutral is bonded to the body of the alternator.
When configured in this manner, the neutrals (utility and generator) should be switched and not permanently connected, if ground fault protection devices are in use.
If the utility supply neutral and the generator supply neutral are both, separately grounded and the neutrals of both sources are permanently connected at the transfer switch; should a ground fault occur, any ground fault current would be split along the neutral into two parallel paths to earth. If the amount of sensed ground fault current does not exceed the settings of any ground fault protection devices fitted (now or in the future) to the faulty circuit, they will be rendered ineffective, quite an important point to bear in mind.
The two main ways to solve this problem are to remove the neutral/earth bond from the alternator, or to switch the neutrals at the transfer switch (both of which would return the full ground fault current through the protection device). In my opinion, switching the neutral is a must.
I understand that MEN (PME) is a consideration, but as it is still not implemented country wide throughout Thailand, I prefer to focus on the viability of the local grounding system and proceed as if MEN is not in place (even if it is).
Genset
...Not sure what happened to the formating of this post, I wrote it in Msoft Word and pasted it into the window... the spacing is a little tight but I cant amend it... sorry.
The attached document explains this problem in more detail and quite clearly...
Edited by genset, 2009-11-23 05:49:41.
Posted 2009-11-23 05:32:56
genset, on 2009-11-21 06:08:10, said: Naam, on 2009-11-21 05:27:08, said: Observer: " Most synchronous generators are designed to support 300% of their rated kVA for 10 seconds. From the OP, [(600 amps starting current)(230 volts single phase)]/1000 = 138 starting kVA"
Genset:"a generator with the correct insulation class (H), may also handle high overcurrent for short periods (such as that mentioned in Naams question), but the potential for alternator insulation failure is high', I followed this up more recently with the comment that things just arent made the way they used to be..."
Gentlemen, assuming both claims are valid it is beyond my comprehension that the supplier of generators (main parts engine and alternator) would try to save cost by being stingy as far as insulation class of the alternator wiring is concerned. in Nigeria i bought the generator together with his twin second hand from a german construction company which withdrew from the country. that was end of 1981, both units were most probably 2-3 years old. and now i am told that after THIRTY years of technical and manufacturing development the products are inferior?
Naam,
No, contemporary alternators are not inferior, far from it, but 300% of rated Kva for 10 seconds equates to an enormous amount of heat being generated in the alternator windings. These recommendations exist to extend the life of an alternator at the end of the day Naam... the manufacturer doesnt want you to burn your alternator out through misuse.
one has to add " the manufacturer wants me to spend a multiple of my dough because he is not willing to produce with an additional minimum of my aforesaid dough the sturdiness of a product i have experienced three decades ago".
Posted 2009-11-23 05:44:45
Quote one has to add "the manufacturer wants me to spend a multiple of my dough because he is not willing to produce with an additional minimum of my aforesaid dough the sturdiness of a product i have experienced three decades ago".
At the end of the day Naam, if you size your generator correctly, use it appropriately and service it regularly, it should give you years of trouble free service... I wouldnt like to see you slide into a fit of depression over this now... 
Genset
Edited by genset, 2009-11-23 05:47:19.
Posted 2009-11-23 08:45:23
genset, on 2009-11-23 05:44:45, said: Quote one has to add "the manufacturer wants me to spend a multiple of my dough because he is not willing to produce with an additional minimum of my aforesaid dough the sturdiness of a product i have experienced three decades ago".
At the end of the day Naam, if you size your generator correctly, use it appropriately and service it regularly, it should give you years of trouble free service... I wouldnt like to see you slide into a fit of depression over this now...
Genset
i am not at all depressed Genset. i stated facts and i see a problem. when i see a problem i am looking for a solution. i do not consider "[over]sizing my generator correctly" an acceptable solution assuming there are other ways, assuming Observer's statement " Most synchronous generators are designed to support 300% of their rated kVA for 10 seconds" is correct and especially based on the actual experience i had years ago with a generator (actually alternator) which quite obviously took loads in a stride which seem to be beyond the capability of some nowadays alternators.
so let's look for a solution apart from oversizing. i am neither a stingy nor a poor man. i've told you what i spent on my home. it does not make a big difference to my bank account whether i spend 300k or one million Baht on my generator. but having grown up as a poor boy in a poor environment and working hard for whatever i own now i hate wasting a single penny.
Posted 2009-11-23 08:57:38
Hi Genset, regarding your post 154.
One would agree with you there. I was pre supposing a MEN system. The TT system is the system most used in Thailand and they may switch the incoming neutral.
AS3000/2007 and AS3010 provide information on generator connection the majority of gensets connected to an MEN system do not switch the neutral and use a 3 pole ATS or 2 x 3 pole contactors (for small sets) or a manual 3 pole C/O switch and only one MEN connection per consumer, the MEN is at the main switchboard.
AS3000/2007 7.3.8.1.
The neutral-earth connection (MEN connection) shall be made within the installation at the switchboard to which the electricity generation system is connected.
Note: This may require disconnection of any neutral-earth connection within an electricity generation system, such as an engine driven generating set.
The incoming neutral to a MEN switchboard shall not be switched.
Neutral and earth conductors shall not operate in parallel.
7.3.8.1.2 Switching.
The changeover device for an alternative supply shall be selected to maintain the function of,and prevent damage to, the electrical installation being supplied.
Note: Examples of functions to be maintained include the maintainance of the continuity of the neutral conductor (overlapping of neutrals), the operation of RCDs or the continued operation of uninterruptible power supplies.
The changeover device shall open all active conductors of the normal supplies when the alternative supply is connected.
Note.
One has to make allowances for Thailand. In Australia we regard neutrals, earthing and equipotential bonding seriously. In Thailand they do not. One may have to use alternative methods as long as electrical safety is not compromised.
Posted 2009-11-23 12:28:45
Naam:
According to the NEMA MG1 Standards, a synchronous generator should have the capability of supporting 300% overcurrent for 10 seconds. The question thus becomes how much of a voltage dip (sag) are you willing to tolerate and still be able to start all your motor loads. Is it acceptable for the lights to noticeably flicker or dim every time an AC starts, what about all your electronics? A lot depends on the generator windings, exciter, voltage regulator, and motor characteristics. If you require an exact answer the manufacturer will have to supply a motor starting capacity curve, or similar analysis, that details the ability of the generator set (as sold) to handle motor starting loads. Without such data being readily available we can only speak in generalizations. And yes, they don't build 'em like they used to.
Edited by InterestedObserver, 2009-11-23 12:53:41.
Posted 2009-11-23 14:50:50
Quote whether i spend 300k or one million Baht on my generator. but having grown up as a poor boy in a poor environment and working hard for whatever i own now i hate wasting a single penny.
Hi Naam,
I appreciate your comments, have attempted to answer your questions to date as honestly as I can and will continue to do so.
Quote so let's look for a solution apart from oversizing
Ok, the first thing we need to correctly size a generator for your needs, is an accurate load calculation based on the starting load requirement of each motor you intend to run and all your other appliances.
Genset
Edited by genset, 2009-11-23 15:22:08.
Posted 2009-11-23 15:11:21
Quote According to the NEMA MG1 Standards, a synchronous generator should have the capability of supporting 300% overcurrent for 10 seconds.
NEMA MG1 further states that (although each insulation class (A,B,F,H) has different characteristics (maximum operational temperature at each class)), under normal, continuous operating conditions, the insulation will have a minimum life expectancy of 30,000 hrs... thats 60yrs at the recommended standby (LRP) rating of 500hrs operation a year... so with a change of engine, you should be good to hand it down to the next generation...
Quote The question thus becomes how much of a voltage dip (sag) are you willing to tolerate and still be able to start all your motor loads. Is it acceptable for the lights to noticeably flicker or dim every time an AC starts, what about all your electronics? A lot depends on the generator windings, exciter, voltage regulator, and motor characteristics. If you require an exact answer the manufacturer will have to supply a motor starting capacity curve, or similar analysis, that details the ability of the generator set (as sold) to handle motor starting loads. Without such data being readily available we can only speak in generalizations. And yes, they don't build 'em like they used to.
Agreed, although I appreciate Naams comments, without the accurate starting load data (as part of a fully comprehensive load calculation) it is difficult to give a precise answer to this question and recommend an appropriate generator size for Naams requirement.
Genset
Edited by genset, 2009-11-23 15:29:45.
Posted 2009-11-23 16:39:37
Quote assuming Observer's statement "Most synchronous generators are designed to support 300% of their rated kVA for 10 seconds" is correct and especially based on the actual experience i had years ago with a generator (actually alternator) which quite obviously took loads in a stride which seem to be beyond the capability of some nowadays alternators.
Hi Naam
I missed this initially (rushing to read your message before running out to work...), but I wouldnt categorize the statement underlined above, as the alternator taking the load in its stride... or as a reflection of an alternators capability to handle the load requirement of motors on start up. Under normal operating conditions (starting motors etc), the alternator should not be required to venture into this territory (we discussed alternator insulation ratings in post #75, if anybody is confused by this disussion I would ask them to read that post again, it contains information relevant to this exchange).
The ability to support 300% of rated Kva for 10 seconds is a safety factor, built in to protect the alternator windings from catastrophic failure and it should not be used as a basis for calculating a load requirement.
The 10 second rating is designed to allow the overcurrent protection device fitted on the generator, to operate effectively and trip the supply from the generator should such a situation occur.
Genset
Edited by genset, 2009-11-23 16:48:52.
Posted 2009-11-23 19:08:09
genset, on 2009-11-23 16:39:37, said: The ability to support 300% of rated Kva for 10 seconds is a safety factor, built in to protect the alternator windings from catastrophic failure and it should not be used as a basis for calculating a load requirement.
that goes without saying but at the same time i read in the recommendations of an alternator manufacturer (you sent by e-mail) of starting currents which are FIVE to TEN times the flying amps. for an electrical layman like me that all sounds very confusing. what i will do is measure the starting currents of the two types of a/c units (12 and 24k btu) i am planning to use as well of the two huge fridges/freezers in my kitchen. unfortunately the chap whom i sent out to buy a "clamp amp" brought a model without peak hold. calling the shop the answer was "no habb". inspite of this i will still try to measure the two units. besides considering these loads i still insist on either manually or otherwise "one after the other switching (after the breaker or with a gadget that replaces the braker) first off and than on.
all my electronics (PCs, TVs, etc. as well as my house water suplly) are on inverters and batterie back-ups. there seem to be another problem to be solved, i.e. (according some experts here) separating the inverters from the net as long as the generator is running. other experts beg to disagree  but if necessary that should not be a big problem to solve.
if you look at the sketch i posted even the "comfort version" is a total of only 12 kW out of which the highest "consumer" draws 2.2 kW. the 12kW contain already an aircon which is not really needed. as i don't have split personalities it is highly unlikely that i sit in front of my screens in my study and watch at the same time news in my TV-room using in both room an aircon simultaneously 
needless to say is that during generator use neither pool pump, nor pond pump, nor waterfall, nor irrigation pump, nor deep well pump will be used.
Posted 2009-11-24 08:01:52
Alternator protection. General.
Overvoltage
Undervoltage
Overspeed (Hz)
Underspeed (Hz)
Short circuit protection.
Overcurrent protection.
Earth fault protection. TT systems.
1. Overvoltage, undervoltage, overspeed and underspeed characteristics should be
incorporated in the AVR.
2. Short circuit and overcurrent protection by a MCB or MCCB of suitable rating.
3. Earth fault protection for generators connected to a TT system.
Earth fault protection is not mandatory in Thailand on TT systems. An earth fault may not operate a protective device.
On a TN (MEN) system an earth fault must be cleared within 0.4secs, the fault current path via the neutral conductor to the source of supply.
Posted 2009-11-24 08:59:51
Quote i read in the recommendations of an alternator manufacturer (you sent by e-mail) of starting currents which are FIVE to TEN times the flying amps. for an electrical layman like me that all sounds very confusing. what i will do is measure the starting currents of the two types of a/c units (12 and 24k btu) i am planning to use as well of the two huge fridges/freezers in my kitchen. unfortunately the chap whom i sent out to buy a "clamp amp" brought a model without peak hold. calling the shop the answer was "no habb". inspite of this i will still try to measure the two units. besides considering these loads i still insist on either manually or otherwise "one after the other switching (after the breaker or with a gadget that replaces the braker) first off and than on.
If you are not in a rush and in an effort to get an accurate load requirement and generator sizing, perhaps you would prefer to wait until I come back in the new year, I would be happy to help you out with this in person.
Genset
Edited by genset, 2009-11-24 09:00:42.
Posted 2009-11-24 15:35:14
InterestedObserver, on 2009-11-23 12:28:45, said: Naam:
According to the NEMA MG1 Standards, a synchronous generator should have the capability of supporting 300% overcurrent for 10 seconds. The question thus becomes how much of a voltage dip (sag) are you willing to tolerate and still be able to start all your motor loads. Is it acceptable for the lights to noticeably flicker or dim every time an AC starts, what about all your electronics? A lot depends on the generator windings, exciter, voltage regulator, and motor characteristics. If you require an exact answer the manufacturer will have to supply a motor starting capacity curve, or similar analysis, that details the ability of the generator set (as sold) to handle motor starting loads. Without such data being readily available we can only speak in generalizations. And yes, they don't build 'em like they used to.
Observer,
i think i emphasised from the beginning that i am planning to go with my idea of switching loads one after the other. if this problem is solved the generator of my liking
http://www.kipor.com...asp?info_id=577
with a continous output of 30kW should not have any problems to deal with the "comfort" solution (12kW) i want to achieve. the unit has to deal only at start with the heavier load of the selected aircons. reason: whenever we lose a phase or even two the remaining aircons work continously, never switch off and because of that no fluctuation (except perhaps a minor one from the fridges) occurs. all my electronics are (as mentioned) on inverters (three sets of them, each with a 24v battery back-up capacity 320ah).
light flickering should also be eliminated as no aircon will switch off and then on again during generator use (see above). besides, having lived and worked 15 years in the desert, the bush and the swamps a little light flickering wouldn't do any harm 
Posted 2009-11-25 06:33:14
Re. #166
Reading the specs of that particular generator, no mention is made of alternator protection,
provision for remote (eg 3 wire) starting or provision for auto start function on loss of mains supply.
The ATS and compatable control module suitable to interface with the genset controls would be an optional extra. If a manual changeover switch is to be used this would be an extra.
The ATS and control module should be purchased from the same source as the generator to ensure compatability.
Posted 2009-11-25 09:06:06
intermediate summary:
-i am presently discussing with Genset the transport of the unit and bombard him with photos i made.
-my choice of generator is a 3-phase unit with a net output of 30kW which should be suitable to run not only my "comfort version" but also a water heater which has no starting load.
-the starting amps have become (in my view) irrelevant because i will switch off all airconditioner breakers when when a power cut occurs. the generator is then started by remote manually. when the diesel is up with its revs (there is still the load of lights and other "consumers") i will switch on manually one needed aircon after the other (again with the breakers). during generator run time no aircon will on its own switch off/on. i explained the reason why before.
-the biggest aircon (24k btu) with the highest starting amps will be switched on first. this unit runs daily at full blast 2 hours, cools down my bedroom to 18ºC (Daikin prevents a lower setting than 18ºC) and is switched off when i go to bed. the achieved temperature is during 8 months in a year low enough to keep the slowly warming up bedroom at a comfortable temperature till i get up again. in very hot nights a 12k btu unit is used to prevent the room from warming up above 25ºC.
what is wrong with my thinking? opinions please, but no soft starters, nothing fully automatic, no timers, no complicated additional wiring and control boxes.
Posted 2009-11-25 15:32:06
Quote Re. #166
Reading the specs of that particular generator, no mention is made of alternator protection.
Alternator protection is provided by the AVR (overvoltage) and an ABB MCB mounted on the set (overcurrent) plus genset controller sensing. Further to this, the ComAp ATS controllers I use (combined with an ATS), also monitor overvoltage/overcurrent and will shut down the set when operating outside of user set parameters.
Quote provision for remote (eg 3 wire) starting or provision for auto start function on loss of mains supply.
The auto start function is provided for by the electronic controller on the set and an ATS wiring harness is in place (meaning only a simple connection is required, not at the controller itself, but an easily accessible connection point). The controller will automatically start the set on receipt of a constant 24v DC B+/B- signal, when the signal stops, the set stops.
Quote The ATS and compatable control module suitable to interface with the genset controls would be an optional extra. If a manual changeover switch is to be used this would be an extra.
Yes, the price of these sets does not include an ATS or (if an automatic transfer switch is not required), a manual transfer/chanegover switch.
Quote The ATS and control module should be purchased from the same source as the generator to ensure compatability.
Compatability is seldom an issue (with most simple ATS control panels such as these) as most ATS controllers use a 12/24v DC B+/B- signal to command a set to start and most electronic genset controllers (mounted on the set), will activate the remote start function on receipt of a 12/24v DC B+/B- signal. The only control wiring between the ATS panel and the generator are a 12/24v DC B+, B- (DC Supply to ATS controller and battery charger) and a single wire remote start.
Genset
Edited by genset, 2009-11-25 16:08:23.
Posted 2009-11-27 22:30:16
What a change; a thread from a sponsor which tries to give us useful, expert information instead of trying to sell us real estate 
I don't live in Thailand but in Sri Lanka, but have just bought a generator as we seem to be returning to the brown-out times of the mid- to end-nineties.
A couple of points about your posts. I am surprised you are recommending small gasoline units for standby. Apart from anything else the cost of an external ATS would erode some of the difference the difference from a specifically designed standby generator.
Another point is that you don't need to back up all the power in the house. You can send the stuff you want to back up, such as computers, lighting, fridges, TV to a separate board and have only that serviced by the standby generator, leaving ACs, clothes dryers and other heavy duty stuff to await the restoration of power.
And a last thing; do you know anything about Tigen generators, specifically the 5.5Kva automatic diesel standby. So far I've had no problems, but who knows?
Posted 2009-11-28 08:14:27
Quote What a change; a thread from a sponsor which tries to give us useful, expert information instead of trying to sell us real estate
Hi Steve, thanks for your comment, it's nice to know that the effort made by myself and other notable contributors to the thread (to offer some useful information) is appreciated 
Quote A couple of points about your posts. I am surprised you are recommending small gasoline units for standby. Apart from anything else the cost of an external ATS would erode some of the difference the difference from a specifically designed standby generator.
I am not 'recommending' small gasoline units for standby use per se, if somebody wants a recommendation for an installation, I will give them my honest opinion based on their specific needs and how much they are willing to invest in a generator. What I am trying to do, is present expats with a range of options for all budgets and standby/prime power needs (which differ greatly from one person to the next). As long as a customer understands the operating characteristics and limitations of high reving (3000rpm) gasoline powered, light duty generators, they are a perfectly acceptable budget option for light duty applications and they will perform satisfactorily when used as per ISO 8528-1:2005 ratings. I have not and never will, attempt to suggest that a 3000rpm genset is acceptable for anything other than limited time operation for light duty applications (for further info on genset ratings please read post #75).
The issue of cost is subjective and should be considered in context, based on a number of different factors. The idea that what you refer to as 'a specifically designed standby generator', should have an ATS located at the generator set (if that is indeed what you are suggesting), is incorrect. Some generators do feature an automatic transfer switch at the set, but my preference is always to locate a separate ATS panel as close as is reasonably possible to the existing distribution board (or sub panel containing critical circuits to be powered by the generator, more below...), but not to mount the ATS on the generator, I particularly dislike the effect sustained vibration can have on an ATS panel when located at the set (furthermore, some users may specify a manual switching option only and forgo the automatic option).
Quote Another point is that you don't need to back up all the power in the house. You can send the stuff you want to back up, such as computers, lighting, fridges, TV to a separate board and have only that serviced by the standby generator, leaving ACs, clothes dryers and other heavy duty stuff to await the restoration of power.
This is true of course, and again, I may be guilty of presuming that most people are aware that a sub-panel linked to critical circuits (in respect to your total load requirement) is a common method of providing a standby generator/ATS partial solution for a domestic installation.
Quote And a last thing; do you know anything about Tigen generators, specifically the 5.5Kva automatic diesel standby. So far I've had no problems, but who knows?
I'm afraid I have never heard of Tigen generators and a google search did not return any results, so I can't tell you if it looks like another generator under a different name. It is very common for large OEM manufacturers to mass produce small generators under many different names for smaller companies. I'm happy to hear the set is running well for you... long may it do so.
Genset
Edited by genset, 2009-11-28 14:53:03.
Posted 2009-11-28 23:12:20
I agree with you it is better to have the ATS switch located near the panel, but beggars often can't be choosers. What I was saying though was that a gasoline generator with an automatic start and separate ATM switch is going to be more expensive than just the generator itself (and of course there is still the question of the generator housing and exhaust valve). Manual start ups are great except when you have the power cut after lights out, or when you're asleep so you don't even know the food is rotting in the fridge.
It was 'Tiger', not 'Tigen' generators by the way. My apologies.
I think you shouldn't overestimate the technical nounce of your users. I only know the basics because I spent a long time googling them.
Incidentally, when you are giving maximum usage times, to get the weekly figure you seem to be dividing the yearly figure by 52. This isn't normally how a standy generator is used. If the snow, or coconut trees, bring down the service it may be off for three or four days, and then scarcely used again for the rest of the year. We've been told to expect cuts most days this month but that after the upgrade is finished they should become rare.
Posted 2009-11-29 03:32:02
Quote What I was saying though was that a gasoline generator with an automatic start and separate ATM switch is going to be more expensive than just the generator itself (and of course there is still the question of the generator housing and exhaust valve). Manual start ups are great except when you have the power cut after lights out, or when you're asleep so you don't even know the food is rotting in the fridge.
Yes, unless a generator has an ATS fitted to it, the price of an automatic switch will always be an additional cost if you want to switch your supply automatically.
ATS panels are very convenient as you suggest, but manual changeover is an option for those who prefer it.
Quote It was 'Tiger', not 'Tigen' generators by the way. My apologies.
Yes, I see they sell portable gasoline and diesel gensets but I have no working knowledge of how their generators perform. I should add that it's no longer the case that everything finding its way out of China is cheap tat... they have upped their game considerably over the past decade and are producing quality (in many areas) to challenge the domination of big established names at a fraction of the cost. I hope your generator continues to operate reliably for you.
Quote I think you shouldn't overestimate the technical nounce of your users. I only know the basics because I spent a long time googling them.
I dont think I have to be honest... when I wrote my original post at the start of this thread, I tried to lay out the information in a clear, logical manner that could be read and more importantly, understood, by a person with no prior knowledge of generators or how they work. Having said that, when a question is raised and drilled down into by other contributors to the thread, it would be rude of me not to take part in those discussions and offer my opinions. Although some of the theory may seem a little intimidating to some readers (I think this may be your point... ), its not my intention to scare them away, and if they read the original post, they should feel quite comfortable in posing (what they may consider to be) the most basic questions regaring the installation and operation of a generator.
Quote Incidentally, when you are giving maximum usage times, to get the weekly figure you seem to be dividing the yearly figure by 52. This isn't normally how a standy generator is used. If the snow, or coconut trees, bring down the service it may be off for three or four days, and then scarcely used again for the rest of the year. We've been told to expect cuts most days this month but that after the upgrade is finished they should become rare.
I must beg to differ with you on this point. In respect to the operation of a standby generator in Thailand; the way I have chosen to describe the maximum recommended hourly operation of the generator (as a weekly figure) reflects the way a standby generator can be expected to be used in Thailand.
That's some location you're living in, where the risk of power outage from heavy snowfall or falling coconut trees is of equal concern...  but seriously... The maximum recommended use for a standby rated generator (Limited Time Running Power LRP) is 500 hours; this total should be accrued during periods of 'limited time running'. Standby generators should not be considered for applications requiring periods of extended use.
For the most part, the utility supply in Thailand is quite reliable, but some provinces in Thailand are affected more than others by a fluctuating utility supply, especially in areas at the end of distribution lines. The most common complaints I hear of, are regular deep brown out conditions, or frequent power outages lasting from 30 minutes to four or five hours on average and occuring throughout the year. They may be more pronounced at certain times of the year (for me, particularly hot summer periods and/or a heavy rainy season up around Khon Kaen spells trouble with my utility supply). Describing the rated use of a standby machine by giving a recommended hourly use per week, is, I hope, something that readers who live in Thailand will be able to relate to.
Genset
Edited by genset, 2009-11-30 08:54:57.
Posted 2009-11-29 16:17:16
genset, on 2009-11-29 03:32:02, said: The maximum recommended use for a standby rated generator (Limited Time Running Power LRP) is 500 hours; whether that 500hrs is accured during two or three periods of use throughout the year, as in your example, or two or three times a month (24 to 36 times a year...) as may be the case in Thailand, the maximum recommended period of use for the generator is the same.
that's a logic i don't understand. since when is a limitation of something mechanical related to a calendar year?
Posted 2009-11-29 16:23:20
Quote The most common complaints I hear of, are regular deep brown out conditions, or frequent power outages lasting from 30 minutes to four or five hours on average and occuring throughout the year. Brownouts or load shedding; the usual reasons.
The snow I referred to came from the normal reasons for getting a generator given on US websites. The falling coconut trees are the excuse we get here when it rains and the power goes, though they normally manage to get it up after a few hours.
I think you did miss out the information about not needing to back up everything in the house, or why you must connect to a switch and not directly to the meter. Both points seem overwhelmingly obvious but they might not be to all your readers or to the wife's cousin who installs the generator and inadvertently fries a few electricity board repair men. And you would be advised to mention that you do need to keep a generator away from the rain and that it it's in a building people are likely to use that the exhaust pipe vents through a hole in the wall if it's a gasoline generator.
It might also be an idea of giving the prices of manual and automatic switches and of the appropriate cabling, or even selling both.
Edited by stevejones123, 2009-11-29 16:47:33.
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