How to Select a Remote Fuel Fill Station for a Diesel Fuel Tank.

Many generator set installations utilize some form of above-ground fuel storage tank, whether it be a freestanding tank, or a “sub-base” tank installed within the generator set skid. Due to space, security or other architectural limitations, the architect and design engineer may be forced to locate the fuel storage tank in a location that is … Read more

How to Prevent a Fuel Overflow Condition in a Fuel Day Tank.

Hospitals, data centers and similar mission-critical buildings rely on their facility’s fuel system to keep their central energy plant running. Due to their sheer size, facility fuel systems can become complex, as many of them now incorporate multiple fuel storage tanks, redundant fuel transfer systems, and multiple fuel day tanks serving large diesel generators.  In an environment where fuel is flowing in such large volumes, … Read more

Separately Derived Systems and 4 Pole Transfer Switches – When and Why?

When reviewing emergency power system designs, I am sometimes asked about 4-pole transfer switches.  The typical question is “when should I use them?“, followed quickly by “why should I use them?“. Since each project is likely to have special circumstances that make a generic answer impossible, this article focuses instead on providing the basic sources of information that should allow you … Read more

Transfer Switch Withstand Ratings: 3-cycle or 30-cycle?

How and when to apply “3-cycle rated” vs. “30-cycle rated” transfer switches should be a rather important consideration for a design engineer.  A coordination study is a critical element that must go hand-in-hand with the design and specification of a safe and reliable emergency power system. Some basic definitions Interrupting ratings  – the highest current at rated voltage that a device is intended … Read more