Civil Engineering Reference
In-Depth Information
TABLE 30-1. Useful Electrical Conversion Formulas
Alternating Current
Single Phase
To Find
Direct Current
Three Phase
Amperes when horse-
power known
hp
746
V
e
hp
746
V
e
PF
hp
746
V
3
e
PF
Amperes when kilo-
watts known
kW
1,000
V
kW
1,000
V
PF
kW
1
,000
V
3
PF
Amperes when kilovolt-
amperes known
kVA
1,000
V
kVA
1,000
V
3
Kilowatts
A
V
1,000
A
V
PF
1,000
A
V
3
PF
1,000
Kilovolt-amperes
A
V
1,000
A
V
3
1,000
Power factor
kW
1,000
kW
kW
1,000
kW
or
or
A
V
kVA
kVA
A
V
3
Horsepower (output)
A
V
e
746
A
V
e
PF
746
A
V
3
e
PF
746
A
amperes;
e
efficiency; hp
horsepower; kVA
kilovolt-amperes; kW
kilowatts; PF
power factor;
volts.
Source:
See Reference 2.
Note:
When used in this table's formulas, power factor and efficiency should be expressed as decimals.
V
ENERGY OPTIMIZATION STUDIES
One of the most common approaches to improving energy efficiency at existing fa-
cilities is to start with an energy optimization evaluation (also called an energy audit).*
Clearly, optimization of energy for water treatment facilities will focus on reducing
energy and demand charges associated with raw and finished water pumping. The next
several subsections describe steps that a water utility should take as part of conducting
this type of study.
Conduct Kickoff Meeting
The agenda for the study's kickoff meeting can include the following:
* This section draws from Reference 4. This section draws from information found in publications by the
Illuminating Engineering Society of North America (IESNA) (see References 5 and 6) and EPRI (see Reference 7).
