- My generator started for its weekly test, I heard a loud noise, banging, squealing, and then stopped. I tried to start it, but wouldn’t turn over. My generator is three years old. HELP!
- My generator came on for the weekly test, made loud noises, and then it started to smoke. I shut it down. I think I need some help.
- I lost my power, the generator ran for about an hour, then I heard a loud noise, and the lights went out. My generator is about four years old. Can you check it out?
What do these three phone calls have in common? All were blown engines. In fact, I have had no less than 40 of these calls in the past four or five years. In the past three months, I had six. All of them were less than five years old.
These are costly repairs, they can run up to $3,000, and many times the customer will choose to buy a new generator.
I have had the opportunity to write many articles, speak to different groups, and even been invited to talk on a radio show about this.
What can cause the generator to ‘die’ prematurely? Improper maintenance is definitely a cause, excess hours can be a cause, improper installation, or under sizing of a generator. The majority of the failures we have run into are under sizing, and this is what I will talk about briefly.
A generator should always be sized for what is called 80 percent of continuous load. Imagine taking your car down the turnpike and going 150 mph for five minutes, then slow down to the speed limit. You probably wouldn’t damage your engine. Now do the same for 48 hours straight, you will most likely blow your engine. It is not designed to run at that high RPM for an extended period of time.
Your generator is the same, it will handle the high load for short period of time, it is not designed to run at the full capacity for an extended period of time.
The most common size generator installed is a 10KW, and most times it will be used as a whole house. A 10KW generator will produce about 42 amps. If you have an electric stove, that stove could use about 40 amps, depending on how many burners or if the oven is used. A dryer could draw about 22 amps, and an electric hot water heater about 22 amps.
A quick way to determine if the generator you are purchasing is sized correctly is to add all your loads, especially the high usage items. Then take the size of the generator you are purchasing, and divide the wattage by 240. This will give you the amperage. Example, a 14KW is 14,000 watts, divided by 240 volts will equal about 58 amps.
Using the 80 percent rule, the max load that should be used is 80 percent times 58 amps, or about 46 amps.
Also note, air conditioners are known as generator killers, and must be taken into account when doing calculations. Ask us why.
We usually use five or six articles to discuss sizing, however, due to space; we need to keep this short. We give free evaluations with no obligation to determine your needs. Contact us and we will discuss your particular needs.
Don’t be a statistic.