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Beth Stackpole
User Rank
Blogger
A scary, but necessary appliance
Beth Stackpole   1/4/2012 6:26:20 AM
That's a pretty scary story, especially for a generator that appears to be pretty new. Despite the helping hand generators can provide, there are some pretty frightening complications if they don't run properly. I'm somewhat surprised that the manufacturer didn't buck up for a full replacement as opposed to simply just fixing the defective model. It would seem that would be a more economical and PR-friendly route than subjecting themselves to a potential lawsuit.

bob from maine
User Rank
Platinum
Generators
bob from maine   1/4/2012 9:43:51 AM
Most small portable generators have the output fixed by design such that the output voltage is a function of speed, there is no voltage regulator. If the generator overspeeds the output voltage will climb proportionately. While it's far from common, it is not that uncommon for a standby generator that sits for long periods to have the governor stick due to rust,  animal hair, or other debris that falls onto the throttle/governor. It happens to lawn mowers and snow blowers as well. Thank goodness for insurance.

Amclaussen
User Rank
Platinum
B & S quality, a thing of the past...
Amclaussen   1/4/2012 9:53:52 AM
NO RATINGS
Sadly, the quality of execution in recent products by old, previously good Brigs and Stratton is aparently going down... vertically.  Friends report me that their Pressure washer by Sears, powered by a Brigs and Stratton gas engine has given them a lot of trouble, in an otherwise "light" home use.  It appears that some parts in the carburetor now come in plastic, and do not perform adequately anymore.  I avoided it, and ended up purchasing a little more expensive Kärcher brand gas engine pressure washer, powered by Honda. so far, my unit always starts at first pull, works beautifully, and produces almost no odor in the exhaust. After some operating hours, the spark plug is very clean, and the exhaust hasn't a trace of soot. Overall, I'm happy with my purchase.  BTW: I've seen a much older 4-cycle Brigs and Stratton engine powering a firepump ina 25 year old building, and it stills works beautifully, proving that previously the quality was there. Amclaussen.

Rob Spiegel
User Rank
Blogger
Re: A scary, but necessary appliance
Rob Spiegel   1/4/2012 10:58:34 AM
NO RATINGS
I agree, Beth. If nothing else, you'd think the insurance company would try to hold the generator manufacturer responsible. I can understand the manufacturer wanting to avoid responsibility, but the insurance company ended up covering costs that were incurred by another company's screw-up.

Rob Spiegel
User Rank
Blogger
Re: Generators
Rob Spiegel   1/4/2012 11:18:47 AM
Wow, Bob from Maine. Sounds like blowing appliances due to the generator could happen often. I would think that would take quite a toll on insurance agencies. I'm surprised insurers don't exclude coverage for customers who use generators that don't have voltage regulators.

Alexander Wolfe
User Rank
Blogger
Re: A scary, but necessary appliance
Alexander Wolfe   1/4/2012 1:03:02 PM
NO RATINGS
If the manufacturer was aware of the flaw, and it sounds from this description that they were, this was clearly a design defect (not only on the part of Troy-Bilt, but also the maker of the VR). I can only infer that time to market pressures are at the root of these kinds of disasters waiting to happen. Either that, or non-deterministic testing techniques and poor QA procedures.

bob from maine
User Rank
Platinum
Re: Generators
bob from maine   1/4/2012 3:37:12 PM
NO RATINGS
Yes, I agree, and insurance claims are fairly frequent, though some subtrifuge may be called for in making the claim: "voltage surge  during recent power failure". At the risk of TMI; Most portable gensets are self excited using permanent magnets so the output voltage is a function of engine speed and current is limited by engine power. An excellent, inexpensive system which works - usually. The governor is a vane type which takes air from the engine flywheel which blows to cool the enigne, the pressure on the vane needs to overcome the governor spring which is designed to pull the throttle to wide-open. There are several pieces in this mechanism, any one of which can jam and prevent proper governor operation. If the generator is used outdoors (it usually is) rain can fall onto the spring and cause some or all of the coils to rust together, thus the vane cannot generate enough force to break the rust apart. Older engines seemed to have somewhat stronger springs of a larger wire size and the vanes were larger. Lawn mowers, snow blowers and other such machines have throttles which usualy create enough force to break the rust but generators are designed to run at a single speed so unless you have a good ear, you can't detect an engine overspeed. Moral is, don't put the generator away wet, as a rule, WD40 sprayed around the carburator will prevent the parts from rusting, keep a 60 or so watt trouble light plugged into the generator, if it blows out, don't turn on the house breakers.

BillyBob
User Rank
Iron
Generator Safety
BillyBob   1/4/2012 3:42:32 PM
I am shocked (no pun intended) that a person would wire low rent generator into their power panel using the main breaker to isolate it from the municipal power.  That is just plain stupid and quite frankly, can kill an unsuspecting power worker just as easily as an "unloaded" gun.  It is absolutely illegal and I am surprised that the insurance company paid and/or the generator manufacturer.

The poor man's way to isolate is to install a second distribution panel.

 [NOT SURE OF THE LEGAL STATUS OF THIS TYPE OF INSTALLATION)

Pull out the wires from the main panel of the circuits  that you want to run with the generator and put them on breakers in the secondary panel.  Then run a 220 30 Amp dryer or welder socket out of the main panel.  Put the matching 30 Amp pigtail on the secondary panel.

From the generator, run a cord with the same type socket that is on the main panel.

In this way, you will be required to unplug the secondary panel from the main power source and physically plug it into the generator extension cord and when the power comes back on, unplug from the generator and plug into the socket from the main power panel.  

With this physical isolation, there is no way you could ACCIDENTLY feed AC back into the grid potentially killing a neighbor or power worker coming into contact with a down 13.5 kV line that looks like it dead ends on your transformer hanging on the pole.

Of course, the best method is to have a CERTIFIED/LICENSED electrician install a transfer switch or at least sign off on the work that you did installing the transfer switch. 

VA Mech Eng
User Rank
Iron
Re: Generators
VA Mech Eng   1/4/2012 7:36:41 PM
NO RATINGS
If you would like to know more about generators you should check out the yahoo group "AC generators".  But first I would like to dispell some misconceptions the commentors here have about small portable generators.  The author of the article said the voltage regulator failed, which I beleive.  Many of the new, small, gasoline powered portable generators use a circuit called an "AVR" or Automatic Voltage Regulator.  This circuit attempts to limit the voltage output by the generator to acceptable levels regardless of the engine speed (within certain limits of course).  The original use was to prevent voltage surges and spikes when the generator has sudden changes in loading (i.e. the refrigerator compressor turn on, or even when it turns off).  Small lightweight portable generators do not have enough rotating mass to maintain rpm during these changes in loading. Although the mechanical governor will eventually bring the speed back to normal (which in the case of the US will either be 1800 or 3600 rpm, usually the higher for small gasoline engines).  The AVR's job is to compensate for the voltage dip (upon loading) or rise (upon unloading) while the governor gets the engines speed back to normal.  It's a good idea in theory, the only problem is AVR's require capicitors to function, these capacitors are usually mounted on the roating part of the generator!  Even if the are mounted stationary, they are still subjected to the vibrations of the engine.  All capacitors will eventually fail, and those subjected to mechanical streses will fail much sooner.  When the caps fail the whole circuit is doomed.  This is the part that most likely failed on the author.  Most light duty residential type generators will fail within 1000 hrs running time even if maintained impecably.   

 

If the generator did in fact have a self exciting permanent magnet setup, then the only component used in it would be a rectifier consisting of 4 diodes.  This arrangement almost never fails.  This is the type of generator that I bought for my house, unfortunately unless you are buying a very large generator to power a commercial building you will not find one made in the US.  The one I bought is chinese, where they still realize that sometimes old and simple (self exciting) is better than new and high tech (AVR).  If your interested in knowing more about this look up the ST style generator heads found on utterpower.com.  If you do a search for ST generator on google you find a link to utterpower follow it and read about a simple robust generator.  My generator also uses a disel engine outfitted with a 80lb flywheel so there is almost no noticble change in engine speed (and therefore frequency and voltage) when the generator has a sudden load/unload event. 

Tim
User Rank
Platinum
Re: Generator Safety
Tim   1/4/2012 7:46:34 PM
NO RATINGS
The use of a certified electrician is great advice. I have heard of a few fires in VA due to improperly wired transfer boxes. I am surprised to hear of issues with a Troy Bilt generator. These are higher dollar and usually higher quality than others. Briggss and Stratton's quick response and payout does look like they knew of the issue and were looking to avoid potential litigation.

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