These generators serve a small data center giving the data center back-up emergency power in the event of a loss of utility. Most data centers have redundant power from the utility and back-up generators. In other words, the utility will provide two sources of utility power from two different power stations or sub-stations so if one source station loses power for whatever reason the system automatically transfers to the back-up source of power or the other power or sub station. The transfer typically takes place through large switch gear systems that will switch from one source to the other source. Automatic transfer switches will offer a delayed transfer so there will be a small amount of time when there will not be any main power supply when the transfer takes place from one utility to the other utility. This where UPS systems fill in the temporary loss of power from one utility to another or from utility to generator power. A data center equipped with a static transfer switch (as opposed to an automatic transfer switch) will not have a temporary loss in power from utility to utility. The static transfer switch has a switchover time in microseconds so the transition is very fast. So fast that a computer cannot read the loss in power so the core load – the computers in the data center – never even blink and keep on working almost as if nothing happened without the UPS back system. The key is to keep the servers running at all times unless the EPO switch is pushed. Power through a UPS system (batteries) and back-up power systems including back-up utility and/or back generators along with the correct switch gear or switching systems will keep the power running all the time – again unless the EPO switch is pressed. The power will continue with the emergency generators when a loss of utility is experienced as long as the emergency generators have a fuel source that is filled up as needed and that the generators are in good mechanical order.