Maximum Demand Indicator (MDI) is an instrument for measuring the maximum amount of electrical energy required by a specific consumer during a given period of time.
MDI instruments record the
base load
The base load (also baseload) is the minimum level of demand on an electrical grid over a span of time, for example, one week. This demand can be met by unvarying power plants or dispatchable generation, depending on which approach has the best m ...
requirement of
electrical energy
Electrical energy is the energy transferred as electric charges move between points with different electric potential, that is, as they move across a voltage, potential difference. As electric potential is lost or gained, work is done changing the ...
. They can also measure the
peak load, but are unable to record sudden
short circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit ...
or high motor starting currents.
The main parts of MDI are:
# Dial connected with moving system
# Pointer on dial
# Reset device
# Fraction device
# Indicating pin
MDI is often available as a built-in feature of
three phase energy meters.
Maximum demand is calculated as: Maximum Demand(KW)=
References
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Energy measurement
Electric power distribution