You are asked to look into adding a circuit for a new pump in a hydraulics lab. After some investigation of the electrical service in the building you find that there are a few voltage options; 120V, single-phase; 208V, single-phase; 208V, 3-phase. Which pump electrical choice would be the most economical in terms of first cost for electrical construction materials and overall electrical efficiency

A single-phase 208V would be the most economical choice for the given case.

A 3-phase 208V pump would be the most efficient choice for the given case.

Explanation:

We are given few options for a new pump in a hydraulics lab.

The options are:

1. Single-phase 120V

2. Single-phase 208V

3. 3-phase 208V

Which pump electrical choice would be the most economical in terms of first cost for electrical construction materials and overall electrical efficiency?

Most Economical:

If we are looking for most economical choice then single phase pump would cost less than 3-phase pump.

We have two options for the single phase pump, 120V and 208V.

If we choose 208V pump then it would provide 208/120 = 1.73 times more power than the 120V pump.

Therefore, single-phase 208V would be most economical choice for the given case. (assuming that 120V and 208V costs same, which is the usual case)

Most Efficient:

A 3-phase pump is more efficient than the single phase pump, therefore, 3-phase 208V pump would be the most efficient choice for the given case.

Conclusion:

For the given options, it is not possible to select the most economical and most efficient pump at the same time, therefore, two different pumps are being selected for this case.