Standby Generator Problems


Old 09-12-04, 12:40 PM
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Standby Generator Problems

I have a standby generator that we use during power outages (yes, we have a transfer switch) and have had some problems with appliances after using the generator. A couple of months ago our Bose radio quit working after using the generator and yesterday when we used it our microwave and cordless phone quit working.

I've checked the ground and it's OK

I've used a volt meter and it registers idential to the regular house current >> 115V and 220V

Maybe it was "just" time for these things to go out, but it would be a strange coincidence that all quit working during the time I used my generator.

Any suggestions on what I should check?

John M.
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Old 09-12-04, 03:29 PM
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You should not use a typical home generator for electronic equipment such as microwave ovens, TVs, and computers. The problem is that the generator will, under heavy load, drop the voltage quite a bit, possibly damaging sensitive electronic equipment. These heavy loads occur when a motor is starting, such as for a sump pump, refrigerator or freezer.

IF you do need to use electronic equipment with a generator you should run it through a UPS or other device that can handle and correct for the voltage problems.
Old 09-12-04, 04:22 PM
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Another thing to consider is the frequency that the unit is operating at.
The frequency is controlled by the speed of the engine and if not correct, the 60 cycles/sec electrical devices require may not be delivered.

I use a larger sized UPS and have my computer on it as well as my fax and answering machine.
Most UPS units are quite sensitive and will often alarm even if there are no noticable power bumps.
This may not work for you though, considering that you are running many different devices that are served by different circuits.

Stand-by generators offer differing qualities of electrical power, some having elaborate power filtering and stability.
Most of the units offered for homeowner use are for what they are sold as, emergency generators.
To produce similar power quality to what your utility offers, would require fairly expensive equipment.

A battery operated radio and an inexpensive manual timer microwave might be your best bet.
Old 09-12-04, 05:13 PM
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Does the UPS have to be one that has a voltage regulator or will a "regular" UPS work OK?
Old 09-13-04, 04:05 PM
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I may not have used the example of my UPS experience properly as I may have left the impression that it will clean up power from a faulty generator.

The acronym UPS is used to describe inexpensive emergency power suplies for computers but they are not truely uninteruptable. The proper term for these but one that I don't see used much is "standby power supply".

How these work is that most of them include a basic surge protection circuit and line monitoring capability. When a device is plugged into these it is receiving power directly from the mains and only has basic surge protection, the type that is included in better power bars. When the monitoring circuit detects a problem with the incoming power it instantly switches with a mechanical relay to the battery within the device.
The power that is then delivered to your electronics is only a partial wave ac power, the same power quality that an inexpensive 12 volt dc inverter will deliver.

This power is only meant for short term use and some equipment can be damaged by it. When used for computers they are only meant to provide power to be able to shut down without data loss.

There is a better type that is quite expensive compared to the basic ones that offers power filtering and cleaning capability, but where the load still operates on utility power until it mechanically switches over.

The third type which is the ultimate but I can guarantee would not be economically feasable in your situation is a truely uninteruptable power source, where the load operates off batteries and power filtration and where the power transition between regular and emergency power is seamless.

Why I have taken the time to tell you this is to make the point that the types of generators that are sold as emergency stand-by units for residential use are for just that, they are meant for survival and BASIC comfort in emergency situations. They are not meant for a residence to maintain everyday comfort and convenience during whatever situation is occuring around them.

What I'm really getting at is that there is no inexpensive solution to your problem.

The generator that you have either has a problem or wasn't designed for what you want to do.

You will get good information on specific generator solutions from a generator supplier that deals in commercial and industrial power supplies. They will be familiar with what specific equipment will fill your needs.

BTW, have you or someone checked the frequency yet?

If you give us the make and model of your unit I may have some info on it.
Old 09-13-04, 06:17 PM
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A UPS is uninterruptible and has battery in it. If you don't have a battery then you don't have a UPS. You have some sort of power filter or conditioner.
A UPS will filter bad power from a generator. It will be beeping if the generator is generating bad power.
Old 09-13-04, 06:41 PM
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A UPS CAN filter power if one spends enough money but the consumer UPS units most folks are familiar with don't, other than basic surge protection.
They will beep when incoming power is bad but when they do they will have switched over to battery, which in the case of consumer UPS units will not be delivering full wave ac power.

I re-read my explanation above and it may have been a bit long winded.
Here is a link to a PDF that may explain it more clearly.
Old 09-13-04, 06:48 PM
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As an additional note, most small generators <6kW, do not have an automatic voltage regulator and may experience voltage fluctuations that will cause your electronics to smoke. This theory was mentioned in an earlier post.
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