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Home / Domestic Power Generator Sets - ATS, AMF, AVR - Automatic Starting, Stopping and Change Over or Transfer. UPS, On-line, 0ff-line and Line interactive |
| |(or, there are only 3 things more amazing than Politicians, that's some Gen set, battery inverter and UPS (or is it UPI ?) salespersons ........) Keep your Garlic handy when shopping for these essential items ..........Feel free to contact us if you have any queries or concerns - advice is free ! |
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Under Construction (especial the spelling and grammar) ....... Born from some 30 years of answering the same questions, over and over and over - and yes, some of my best friends are Gen set and ups salespersons, they have even been to my house..... |
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| So, the salesman has done a fantastic job convincing you that this is the Generator Set for you, just the set for home and the answer to all the load shedding, blackouts, power quality problems, the Model 6500 SUX ! The spectacular demonstration of the 6500 SUX running a large, power hungry looking angle grinder or other heavy duty appliance proves it, right ? After all, when compared with the initial costs of Solar Power, the Gen Set has to be the way to go, unless you have just won the Lottery. |
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| The answer is 'yes' if you are planning to work on a construction site where automatic regulation of the power output of the generator is not critical, but maybe 'no' for home use, especially if you plan to use it for running sensitive electronic equipment, such as that expensive Home Theater System your wife just let you buy ........ |
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| Lets look at the tricks and traps of the Generator set world; |
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1). If you have decided to buy a Gen set for home,
the first thing you should purchase is a fuel type Fire Extinguisher,
preferably 2, one to be kept in the location of the Gen set, and the
other in a suitable location in the house so that it can easily and
quickly be picked up and taken to be used in the location of the
Gen set. Remember, you are now dealing with both having to keep
"bulk" fuel on hand and may have to refuel a hot Gen set if
it has been running for a long period. Avoid refueling hot or warm Gen
sets where at all possible.
Now, you can get out your household cover insurance contract and read up for any nullifications introducing a Gen or 'bulk' fuel may bring and if necessary, have the cover amended. |
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| 2). Always remember that a running Gen set produces poisonous Carbon Monoxide exhaust fumes. The Gen set must be sited in a well ventilated area where the exhaust fumes will easily dissipate and to assist the Gen set with cooling while running. Make sure that exhaust fumes cannot find their into the living or sleeping areas of you home. Apart from the smell of the fumes, a dull headache that only occurs when the Gen set is running is a sure sign of the presence of fumes. |
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| 3). Mom's, remember that Gen sets, especially the exhaust, can get very hot and small fingers could just find their way into moving parts. Position the Gen set accordingly and make sure the little people cant get to it, or its wiring. Basic First aid kit ? All emergency telephone numbers listed and handy ? Your DIY Hubby will need them ! |
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4). Noise - Consider a silent neighborhood
with no power and your Gen set thundering away in the background .......
If the neighbors don't get you, the Municipality will ! As soon as the
power is off out comes the inspectors armed with noise meters. Like all
good authorities / enforcers, they will get you both ways, one by there
being no power and two by busting you for making noise while there is no
power. This is where the saying; 'suffer in silence' must originate ?
Look at an enclosed or silenced Gen set, or install your Gen set in a position or area where the noise is least likely to affect anyone. Super Silent Gen sets are now available at a reasonable extra cost. |
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| Now for the traps or the boring technical stuff that the salesman usually skips over and usually is only recorded in the fine print of the Gen set manual or users handbook; |
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a). Just because the set is marked
"6500" doesn't mean that it can produce that amount of usable
power;
Usually the figure is the 'vA' or 'volt /amps' rating for the set. (It could be quoted as: 6.5kVa for example). This figure is subject to the 'PF' or "power factor" rating (a form of efficiency indicator) of the Gen set. This could be as 'good' as 1 or as 'bad' as 0.7 . To find the amount of "useable power" or Watts the set can produce; multiply the vA rating by the PF. The PF is usually around 0.8 or 80% of the vA rating. Already our model 6500 has had a 20% de-rating. Check carefully on this as often the model may be quoted as the "6500" and in reality may actually be 6300, in a similar manner as car manufacturers will quote the vehicle as being the "2.0 liter" model and the actual rating is "1.89 liters". |
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b). The next trick is something called the 'Prime'
and "Standby" ratings;
The prime rating is the amount of useable power the Gen set can produce under constant, normal running conditions. The Standby rating which is usually higher and often what is quoted as the Gen sets capacity, is a figure that the Gen set can produce, for a short period of extra loading. This figure is conventionally quoted as; 'x'% for 'y' minutes. For example: 110% for 10mins. After this period has been exceeded and the Gen set has not be reduced to a normal or prime load, its very likely to be badly damaged. Check in the fine print of the users manual for these figures and remember that many foreign manufactures of Gen set may have a slightly different way of quoting this, but the concept is the same. |
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c). Sea Level or Inland ?
Now here is the real surprise; that vast majority of Gen set ratings are quoted for the Gen set being operated at Sea Level. Johannesburg is at just over 1500 meters above sea level where there is a lot less oxygen in the air that the Gen set will be taking in. The net result is that the Gen set cannot produce as much power as its designed to do and needs to be de-rated for altitude. For 1500 meters above sea level this de-rating is conventionally 20% and is a straight 20% reduction of the usable power a Gen set can be expected to produce. (Remember this was mentioned above ?) This figure is worsened if fuel of the suggested octane or RON rating is lower than recommended. This is exactly the same principle as is applied to motor vehicles. Ever noticed how much better your car runs down at the coast ? Ask the salesman or make certain with the wholesaler or supplier, the Gen set fuel system is set up for above 1500m above sea level, if not, the Gen set will not be operating optimally and will waste fuel. (Too much fuel and not enough oxygen). |
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So, lets have a look at a practical example to put
this all into perspective: (taken from an actual incident);
An imported, open frame, air cooled, petrol (or gasoline) electric start Gen set was offered as the Model "6500". In reviewing the users manual as the manufacturers information plate was not placed so as to be easily read, (strange that ?) it was noted that the actual Prime rating of the set was 5,000w (or 5Kw). The Standby rating was given as 5500w (or 5.5kW). In applying the conventional altitude de-rating, the corrected Prime rating is 4000w (or 4kW). To put this into perspective; a modern quick boil kettle uses 2000 watts and the average 250 liter electric Geyer, the full 4000 watts when heating. A normal old fashioned light globe will use between 60 and 100 watts, while a modern CFL bulb roughly one third for the equivalent output of light. |
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c). Automatic what ? Automatic Voltage
Regulator or AVR;
This is the critical component that the Gen set must be fitted / supplied with to ensure the Gen set does not damage appliances and other sensitive electrical / electronic its powering. Small but critical, it keeps the output of the Gen set stable regardless of fluctuating speed and as and when you turn on and off appliances powered by the Gen set. This is quite different to the Gen set having an "automatic governor" or "automatic speed regulator" which some confused salespeople may offer as an alternative. If you are not 100% satisfied that the Gen set does have an AVR, then rather don't purchase it, look for one that does. Accompanied by 'the must' have AVR is often; "Boet, your mustn't run your PC or home entertainment system off of the Gen set unless you have UPS for them ............" and of course, any Gen set purveyor, or purveyors of battery powered invertors will either have the ideal UPS just handy, or have a contact who can supply you one. Really ? I must be doing something wrong, for years all of my equipment has been running from a Gen set with a proper AVR ? Like Gen sets, UPS's are a minefield all of their own and most found in the domestic or small office world are very often grandly called 'line interactive' or, to those of us who remember Valve Radios and TVs'; 'off line' UPS's. 'Off line', because they are 'of line' or pass the mains power straight through while generally acceptable levels and quality of mains power are present even if coming in from your Gen set, then switch over to their own internal 'generator' or inverter, when the incoming supply goes out of parameters or fails. They will stay running internally until the power returns and when appropriate switch back, so in most cases are just acting an expensive power filters and 'dip filler', that recharge themselves when 'off line' drawing very little from the mains or Gen set. Certainly useful to stop any work on the PC's being lost. For true UPS protection you should have an; 'on-line', 'pure sine wave', UPS unit which is probably a cost overkill for modern appliances like a PC or home theater system. An on-line system does exactly what it name suggests, that is it produces internally a pure, clean form of 'synthetic' power all the time, regardless and independently of what the incoming mains is doing, so your expensive appliances never get to meet the horrors of the outside world of power. Of course, on-line UPS's have batteries in them to keep everything running smoothly should the mains fail, or while waiting for the Gen set to start up, and these batteries generally larger that those found in line interactive UPS's. The shortcoming of this is that these UPS's draw twice the amount of power they produce, 'x1' to supply the equipment the UPS is running and 'x2' to charge the internal batteries all the time. this means they will put approximately twice the load on the mains or Gen set supply when running normally. Err, um, I should mention that online UPS's cost a lot more than line interactive units do and as a 'safety device', often have a 'bypass' in them that will automatically and usually without notice switch over to raw mains should they become faulty. The manufacturers do this because of some kind misguided thought around 'up time' (i.e. keeping the power on), but kinda defeats the object if it exposes your extensive Hi Fi investment to ESCOM running amuck. Having said that, on-line sine wave UPS units are now becoming cheap enough to be an effective purchase for the home / small office and provided excellent protection against all those power dips, surges and variations that are now occurring as the poorly maintained electrical grid struggles to cope with the demand and big brother ESCOM battles to keep up with the demand and maintain quality of supply to first world standards. So, dear readers, choose carefully and wisely .......the compromise in this tricky world is a decent quality power conditioner - a whole other story ...... In short; first prize; Gen set and on-line UPS with the UPS supplying those sensitive and expensive electronic goodies you have. BTW, the small, inexpensive line interactive UPS's make dandy little emergency lights, when coupled with modern CFL light fittings and are quick and easy to install. err No ..... UPS's are not intended for the large power hungry appliances like; fridges, kettles, hairdryers, electric heaters, laser printers et al, that is, of course, unless you want to by a monster UPS unit and increase your electric bill several fold .... Rather stick to the more cost effective and efficient Gen set ? OK ? Read on for more info ...... |
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d). Things that go Bump in the night;
Ever wonder about one of life great mysteries with electrical equipment, especially the good, old fashioned light bulb, how it will blow the millisecond your turn it on, or fizzle and die as its turned on ? (see: www.centennialbulb.org/ if you don't believe me). Likewise appliances, "was working fine till the power went off and when the power came back on, it just didn't work any more". Well, wonder no more ! the answer is; "surge", that initial surge or inrush of power, when the devise is turned on, or, as the Lords of Darkness cut your supply and you turned on the Gen set. Now most well designed appliances are designed to withstand this, but some, or plain old, old age are just susceptible to surge's spikes, bumps, dips, brown outs and especial good old lightning in the direct vicinity. Well, what to do ? Dealing with surges, especially those caused by lightening and sometimes by uncaring power station operators are expensive to effectively deal with, and are never 100% fool proof. Proper surge protection and an essential that goes with it, earthing, generally require a specialist is examine the installation and suggest some usually expensive solutions. 'Earth' or 'earthing' is the primary and fundamental safety in electricity, so no DIY or "making a plan" with it, please - ever ! However, there are some basics you can follow: 1 - Switch off and unplug ("isolate") if you can until either the lightning has passed or the mains power, or your Gen set power has been on for a while. A 3 to 5 min wait is usually sufficient. Especial Fridges, Freezers, Aircons, any form of electric motor and Geysers. 2 - Invest in good quality, well designed surge protecting Plug Tops ("point of supply" protection), but remember, these are largely useless if the earthing in the house electrical installation or for the Gen set supply is not working optimally. Same applies to "trip switches" or circuit breakers. These expensive plug tops can stop a reasonable number of surges, spikes and bumps and regardless of whether actually struck by a surge or lightening and should be replaced every year, usually just before the rainy season starts. 3 - For a little more of your hard earned cash, a larger capacity more effective surge protector can be installed in your electrical DB or switch board, giving you a better level of comfort ("whole house protection"). These units usually have indicator lights on them that tell you when they need to be exchanged. Just by the way, that gizmo in your switch board called the "Earth Leakage" also provides a level of surge protection and is truly a life saver in case of accidental human contact with the electric power, provided its working and tested regularly. When last did you actually test yours and suggest that you do it every month without fail ... (Wives, start nagging !). Remember, with few exceptions domestic surge protection relies on properly working and maintained, Earth Leakage Units, Trip Switches and fuses. Earth Leakage Units are a life saver ! 4 - Connected to life's great mystery of why appliances dies just as your turn them on is the sub mystery of why Fridge's, Freezers and Aircon unit, all suddenly sound if they are 'laboring' or are 'struggling', especially after a short "bump" in the power supply. Well, that is because they are ! Unless well designed and fitted with a sensible design precaution known as a gas pressure sensor or switch, the fridge or aircon unit is struggling to restart against internal pressure that is not usually there. Left unattended, this problem will lead to an expensive bill for a new compressor, dryer and gas, but can be sorted with a little bit of electrical know-how. There are commercially available refrigeration protection units sold in SA, but are not easily found. Ask your friendly electrical contractor or electrical wholesale, or have a look on the 'net. As a solution, the home grown "Fridge Friend" is the answer. It has also been designed to help your Gen set along by ensuring if you have multiple fridges or other power vampires in the house, it keeps them switched off and isolated for a while to allow the Gen set to warm up and settle down, then switches them back on in timed, individual, intervals helping the Gen set to cope. Not only that, if the power supply to these devices is out of acceptable quality / stability norms, it keeps the device switched off and 'isolated' from the supply until the quality supply returns and has been stable for a while, providing further sensible protection. Oh yes, it also contains its own advanced point of protection, protection ....... Contact us for details, as they say in the adds. contactATbaragwanathDOTcoDOTza |
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