ELECTRICAL ACTUATORS Josep Amat and Alcia Casals Automatic

ELECTRICAL ACTUATORS Josep Amat and Alícia Casals Automatic Control and Computer Engineering Department

ACTUATORS 1 – Pneumatic actuators Cylinders Motors 2 – Hydraulic actuadors Cylinders Motors 3 – Electrical actuators D. C. motors. A. C. motors Steeper motors.

D. C. Motors. F Force. H I Motor

D. C. Motors. Motor torque with a one turn coil Motor torque with two turns coil Brushes Motor torque with multiple turns coil

Casing Stator Rotor

D. C. Motors. Stator (Inductor) Rotor (Induced) Serial excitation Parallel excitation

D. C. Motors. I Stator V = I· (Re + Rr) + Vcem T = K I ·F I V Vcem = Kv· w T Tr V 1 w v 2 w. O , Serial excitation w. O

D. C. Motors. I Stator V = I· (Re + Rr) + Vcem T = K I ·F o V Vcem = Kv· w T V 1 V 2 Permanent magnet dc motor Tr w w. O

D. C. Motors. Control techniques PWM

A. C. Motors. 50 Hz. 3. 000 r. p. m. 50 Hz. = 50 r. p. s x 60 = 3. 000 r. p. m. Triphasic voltage produces a rotator magnetic field that steers the rotor, if it is a magnet

A. C. Motors. ac F 0 = 50 Hz. The permanent magnet triphasic motor has a constant speed. Synchronic motor

A. C. Motors. Control techniques ac/dc dc/ac f The speed of a triphasic motor with permanent magnet rotor can be controlled by varying the frequency of the feeding signals.

A. C. Motors. +V 0 V AB A B Control technique: using a dc / ac converter

Electrical Actuators DC Motors. AC Motors. Stepper Motors Synchronous Asynchronous (Induction)

U V W V V S N U U W W Synchronous A. C. Motor the rotor is a permanent magnet i Induction motor (asynchronous), the rotor is composed of one or more windings in short-circuit

Rotor of an asyncronous a. c. motor (Rotor as squirrel cage)

A. C. Motor. D. C. Motor. T T Tr v 2 V 1 w 1 A B (Synchronous) w. O f 1 w w 1 Tr w

A. C. Motor. D. C. Motor. T (Synchronous) T Tr V 2 V 1 w 1 U V Tr w. O W w w 2 w 0 w f 0 = 50 Hz.

Stepper Motors S S N S S S N N N S N N Control of the position of the rotor in a stepper motor using multiple pole pairs

Stepper Motors N S S S N S N N N S N Reduction of the number of pole pairs to a minimum, groups of three that share the same coils: Three phases stepper motor

Stepper Motors N S S N S N N S S S N S Stepper motor control in three phases N S N

Stepper motors. 0 N S N S N S N S N S N S N S N S N S N 1 S N S N S N S N S N S 1 0 S N S N S N S N S N S Control of a two bodies stepper motor of two phases

Internal structure of a two bodies stepper motor, of two phases

Stepper Motors. Control techniques of a two phases stepper motor