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intelligent
Motor control center
Motor control center
Power distribuƟon sLJstems used in plicaƟons, quite a few electric motors
large commercial and industrial appli- are required, and it is oŌen desirable
caƟons can be compledž. Power maLJ to control some or all of the motors
be distributed through switchgear, from a central locaƟon .The apparatus
switchboards, transformers, and panel designed for this funcƟon is the motor
boards. Power distributed throughout control center (MCC).
a commercial or industrial applicaƟon
is used for a varietLJ of applicaƟons
such as heaƟng, cooling, lighƟng, and
motor-driven machinerLJ. hnlike other
tLJpes of power distribuƟon equip-
ment, which are used with a varietLJ
of load tLJpes, motor control centers
primarilLJ control the distribuƟon of
power to electric motors.
In manLJ commercial and industrial ap-
Power Supplies:
Three-Phase Voltage:
Motor RotaƟon:
In most large commercial and indus-
ƚƌŝĂů ŵŽƚŽƌ ĂƉƉůŝĐĂƟŽŶƐ͕ ƚŚƌĞĞͲƉŚĂƐĞ
power is used. In a three-phase sys- Three-phase voltage is
tem, the generator produces three used throughout large
voltages. Each voltage phase rises commercial and indus-
ĂŶĚ ĨĂůůƐ Ăƚ ƚŚĞ ƐĂŵĞ ĨƌĞƋƵĞŶĐLJ ;ϲϬ ƚƌŝĂů ĨĂĐŝůŝƟĞƐ ƚŽ ƌƵŶ
,nj ŝŶ ƚŚĞ h͘^͕͘ ϱϬ ,nj ŝŶ ŵĂŶLJ ŽƚŚĞƌ ŵŽƚŽƌƐ͘ Ŷ ŵŽƚŽƌ ŝƐ
ĐŽƵŶƚƌŝĞƐͿ͖ ŚŽǁĞǀĞƌ͕ ƚŚĞ ƉŚĂƐĞƐ ĂƌĞ ŵĂĚĞ ƵƉ ŽĨ Ă ƐƚĂƟŽŶ-
ŽīƐĞƚ ďLJ ϭϮϬΣ ĨƌŽŵ ĞĂĐŚ ŽƚŚĞƌ͘ The major source of electrical power ary member, called a
used by motor control centers is an ƐƚĂƚŽƌ͕ ĂŶĚ Ă ƌŽƚĂƟŶŐ
ŐĞŶĞƌĂƚŽƌ ůŽĐĂƚĞĚ Ăƚ Ă ƉŽǁĞƌ member, called a rotor.
ŐĞŶĞƌĂƟŶŐ ĨĂĐŝůŝƚLJ͘ ŐĞŶĞƌĂƚŽƌƐ dŚƌĞĞͲƉŚĂƐĞ ƉŽǁĞƌ
operate on the theory of electro- is applied to the stator
ŵĂŐŶĞƟĐ ŝŶĚƵĐƟŽŶ ͘dŚŝƐ ƐŝŵƉůLJ through the power
means that when conductors are ĐŽŶŶĞĐƟŽŶƐ͘
ŵŽǀĞĚ ƚŚƌŽƵŐŚ Ă ŵĂŐŶĞƟĐ ĮĞůĚ͕ Ă
voltage is induced into the conduc-
ƚŽƌƐ͘ ďĂƐŝĐ ŐĞŶĞƌĂƚŽƌ ĐŽŶƐŝƐƚƐ ŽĨ
Ă ŵĂŐŶĞƟĐ ĮĞůĚ͕ ĂŶ ĂƌŵĂƚƵƌĞ͕ ƐůŝƉ
rings, brushes, and some type of
ƌĞƐŝƐƟǀĞ ůŽĂĚ͘
244
