Rockwell Automation 1403-DM_LM_MM Powermonitor II Instruction Sheet - Manual (Page 81)

1403-IN001A-US-P
Appendix
D
Glossary
A
ampere
A unit of electrical current or rate of flow of
electrons. One volt across one ohm of resistance
causes a current flow of one ampere. A flow of one
coulomb per second equals one
apparent power
The product of voltage magnitude and current
magnitude in a circuit. Units are VA, or some
multiple thereof.
B
balanced load
An alternating, current power system consisting of
more than two current carrying conductors in which
these current carrying conductors all carry the same
current.
billing demand
The demand level that a utility uses to calculate the
demand charges on the current month’s bill. Various
methods may be used to determine the value, such as
minimum demand, peak demand or a ratchet clause.
It can be based on Watt Demand, VA Demand, VAR
Demand or some combination of these. A rate at
which a transmission occurs, where one baud equals
one bit per second.
burden
The electrical load placed on source of VA or the
load an instrument or meter places on a current or
potential transformer. All current and potential
transformers have a rated burden which should not be
exceeded or else transformer transformation
accuracy will deteriorate.
C
capacitor
A device consisting essentially of two conducting
surfaces separated by an insulating material or
dielectric. A capacitor stores electrical energy, blocks
the flow of direct current, and permits the flow of
alternating current to a degree dependent upon the
capacitance and frequency. They may also be used to
adjust the power factor in a system.
connected load
The total load which a customer can impose on the
electrical system if everything was connected at one
time. Connected loads can be measured in
horsepower, watts or volt-amperes. Some rate
schedules establish a minimum demand charge by
imposing a fee per unit of connected load.
current transformer (CT)
A transformer, intended for measuring or control
purposes, designed to have its primary winding
connected in series with a conductor carrying the
current to be measured or controlled. CT’s step down
high currents to lower values which can be used by
measuring instruments.
current transformer ratio
The ratio of primary amperes divided by secondary
amperes.
D
demand hours
The equivalent number of hours in a month during
which the peak demand is fully utilized. In other
words, if energy consumption for the current month
is X kwhr and the peak demand is Y Kw, then the
demand hours is equal to X/Y hours. The higher the
number of demand hours the better the demand
leveling situation and the more effectively demand is
being used.