Intermediate Emergency Power Systems

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Key Questions

The following key questions are answered in this module:

What is the generator head?
The generator head is a rotary, electro-mechanical device, which produces electricity at a desired voltage and amperage according to the RPM and horsepower with which it is driven.

What is "wet stacking"?
"Wet stacking" is a condition that occurs in diesel engines when the fuel doesn't get burned completely.

What type of engines do most standby generators use?
Most standby generators utilize diesel engines to drive the generator.

What is the automatic transfer switch (ATS)?
The automatic transfer switch (ATS) is a "smart" electro-mechanical device intended to automatically switch a load from the usual, utility-supplied power, over to generator-supplied power.

What should the PPE consist of when inspecting batteries?
This PPE typically consists of acid-resistant gloves, safety glasses, and an acid-resistant face shield.

Sample Video Transcript

Below is a transcript of the video sample provided for this module:

The diesel-fueled engine is the type of internal combustion engine used most often to run emergency generators. Our discussion will deal primarily with that type of engine. Diesel engines are used in many stationary, long-running applications, due to their inherent reliability. Diesel fuel is readily available, relatively inexpensive, and easily stored. Diesel fuel doesn't ignite very quickly (unlike gasoline, natural gas or propane which are also sometimes used as generator engine fuels). A diesel engine doesn't require a separate "spark ignition" system to function. It operates by compressing the fuel/air mixture introduced into each cylinder, to very high pressure so that the heat of compression ignites the fuel. However, to operate correctly, the fuel/air mixture must be introduced into the cylinders at precisely the right time. For this task, diesel engines use timed fuel injectors, which do precisely what their name implies. Due to its operating characteristics, a diesel engine is more substantially built than a gasoline engine. One powerful suggestion – never let any diesel engine run entirely out of fuel. If that happens, it will be necessary to "bleed" the fuel injector lines, to get rid of all the air the system will have picked up. This is one of the reasons that most fuel storage tanks for diesel engines are located several feet above the engine itself. This allows gravity to supply a continuous flow of diesel fuel.