Difficulties in using 3-phase Generators with 1-phase loads – Solution

The modern user needs backup power for electrical equipment with 3-phase as well as 1-phase loads.

Difficulties in using 3-phase generators with 1-phase loads

It can be seen from the formulas that with the same power of three-phase and single-phase generators, their maximum load currents are different. For a three-phase generator the current is approximately three times less. Only a symmetrical three-phase load or a single-phase load with an equal distribution between phases is allowed to be connected to a 3-phase generator. If we connect the entire single-phase load of the same power to a three-phase generator on one phase, then this winding will burn out from overload. The rest windings will be underloaded and will not burn out, but the generator will still be damaged and cannot be used for its purpose.

As is known, a classic 3-phase generator must have a balanced load across all three phases. So, for example, we use a conventional generator with a power of 20 kVA. In this case, we can apply a 3-phase load of the declared power, but at the same time we cannot apply a 1-phase load of the same power.

This is often a problem.

How to solve the problem of 1-phase load on a 3-phase generator?

First solution.

We can use two different generators, one 3-phase to power a 3-phase load and a second one, single-phase to power other equipment of required power.

Second option.

We can also use a more powerful generator, let's say 30 kVA, which can provide power to a 1-phase load with a specified power rate of approximately 10 kVA and simultaneously energize 3-phase equipment.

Both options allow users to solve the problem of connecting 1-phase devices to a 3-phase generator, but their application has a number of negative aspects. These include: increased fuel consumption, the need for two generators, transport costs, increased noise level. In general, however, if during work or public events there is a need for the simultaneous use of 1-phase and 3-phase devices, the above methods allow users to get out of the situation

Note: For an alternative option of using a 3-phase generator with a single-phase load, read the article - What is a Simul Phase generator and what are its advantages?