2. Contoso
S u i t e s
2
Classic control :-
▪ Motor
❑ 3 phase induction Motor
3. Contoso
S u i t e s
3
Classic control :-
▪ Motor
❑ 3 phase induction Motor 80 % of industrial loads
▪ Stator : provides a rotating magnetic field that drives the rotating
armature which called rotor this field rotate with a speed
called synchronous speed
▪ synchronous speed NS = (120*F) / P rpm
4. Contoso
S u i t e s
4
Classic control :-
▪ Motor
❑ Rotor : the moving part, which turns the shaft to deliver the mechanical power
▪ Wound rotor
▪ Squirrel-cage rotor
▪ rotor speed Nr = (1-s) Ns rpm
5. Contoso
S u i t e s
5
Classic control :-
▪ Contactor
❑ Coil
❑ Auxiliary contacts
❑ Main contacts
❑ Parts in contactor used To connect and disconnect our loads
▪ DC powered coils, they generate a constant magnetic field that guarantees an appropriate
closing of the contacts
▪ AC powered coils generate sinusoidal magnetic fields which produce a force
that drops to zero twice each cycle (50/60 Hz). This creates an undesired
chatter or pulsation of the contacts. This harmful effect can be cancelled by
using a shading ring placed in the contactor core
▪ It is an electromagnetic switch which use magnetic field to open and Close its contacts
8. Contoso
S u i t e s
8
Classic control :-
▪ Contactor
▪ Power of your load or its maximum current
▪ Range of voltage of control circuit “to select coil”
▪ Number of auxiliary contacts and its type “NO, NC”
❑ There are some important information that you must know.
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Classic control :-
▪ Overload
▪ An electric overload occurs when too much current passes through
electric wires. The wires heat and can melt, with the risk of starting a fire.
▪ Overload causes
1- Mechanical “ fraction , …..”
2- Electrical reasons “ Phase drop ,…..”
10. Contoso
S u i t e s
10
Classic control :-
▪ Overload
11. Contoso
S u i t e s
11
Classic control :-
▪ Overload
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S u i t e s
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Classic control :-
▪ Overload
13. Contoso
S u i t e s
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Classic control :-
▪ Over & Under Voltage
▪ Over voltage : When the voltage in a circuit
or part of it is raised above its upper design limit
▪ Over voltage : When the voltage in a circuit
or part of it is raised above its upper design limit
Hazardous. Depending on its duration
▪ Over voltage : When the voltage in a circuit
or part of it is raised above its upper design limit
▪ Under voltage : When the voltage in a circuit
or part of it drops below intended levels
Hazardous. Depending on its duration
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S u i t e s
14
Classic control :-
▪ phase sequence
▪ Phase sequence is the order in which the voltage waveforms of a
polyphase AC source reach their respective peaks. For a three-phase
system, there are only two possible phase sequences: 1-2-3 and 3-2-1,
corresponding to the two possible directions of alternator rotation.
