EASTERN MEDITERRANEAN UNIVERSITY
FACULTY OF ENGINEERING
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
EENG 320 LAB HANDOUT #1
System Familiarization
Course Instructor: Prof. Dr. Runyi Yu
Lab Assistant: Faezeh Yeganli
Objective:
In this lab you will familiar with some equipments that will used for obtaining DC motor
characteristics.
 Equipments
The equipment which will be used for the servo technology exercises is described below.
 Base Unit
Base unit 2000 (Figure 1) is general unit for connection to various equipments in
system 2000 concept. The base unit runs on 230 VAC. Various modular circuit
boards are inserted between a pair of board guides and connected there to 64 pole
sleeve member for energizing the board.
 Support Plate
The exercises are performed on support plate (Figure 2) with a journalled shaft
which carries an indexed protractor to indicate the shafts position. Mounted on the
shaft are:
1. An encoder for speed measurement.
2. A shaft coupling for connecting motors.
3. A shaft coupling for connecting a position sensor, a feed-back value
potentiometer, a brake or a flywheel for loading the motor.
4. A toothed belt for connection to a linear unit.
5. A linear unit.
Next the shaft there is a motor attachment with four snap locks.
Figure 1.Base Unit 2000.
Figure 2.The Suppot Plate.
 Motors
The various servo motors are mounted on a plate which is fitted to the servo
system attachment and locked in position by turning the snap locks. The motor shaft
is then mounted in line with the shaft and fixed in a position where it ahs been jacked
into the shaft coupling.
Figure 3. The motors are connected with bayonet coupling turned through 90.
The Servosystem 2000 training kit includes the following servo motors:
1. 12 V DC servo motor for direct connection to the servo system.
2. 12 V DC servo motor with in-built gear for reducing the shaft speed.
3. AC Stepper motor, 1.8 0 / step.
An AC servo motor can also be connected together with drive stage; see Servo
Amplifier presentation overleaf.
 Sensors
A digital pulse sensor (Figure 4), known as an encoder, is permanently
mounted on the journalled shaft. When the shaft rotates, a pulse disc with a large
number of paths rotates with it. In the sensor, the pulse disc is combined with a
light source and photodiodes. The pulse disc emits 500 pulses per revolution and
consist of two channels, so that it can also indicate the direction of rotation.
Figure 4.The pulse disc, showing light source and photodiodes.
Analogue position sensor (Figure 5), an analogue position sensor can be connected via a
shaft coupling. This is a potentiometer, the moving part of which follows the torsion of the shaft.
The potentiometer is single-wound, with an electric angle of 320 0 . The potentiometer has no end
stop, and it accompanies the shaft, continuously changing its resistance.
 Servo Amplifier
Various electronics boards, connected to Base Unit 2000, are used for driving the
different motors. The following control boards (Figure 6) are used:
1. Servo regulator, SR1.
2. Velocity control module, SR2.
3. Position control module, SR3.
4. Stepper Motor module, SM1.
Figure 5. The potentiometer is connected to the servo system shaft by means of a shaft.
Figure 6. The control boards.
 Flywheel
Servosystem 2000 is loaded by connecting a flywheel (Figure 7) to the motor by
means of shaft coupling. The flywheel weighs 300 g.
Figure 7. The flywheel fitted to the base plate.
 Generator brake
For stepless adjustment of various loads, a generator brake is connected to the
motor shaft. The brake action can be varied by means of a potentiometer.
 Linear unit
Movement with a linear unit (Figure 9) is used for a fast feed movement over a
short distance. The combination of screw and nut makes for steady, even travel. The
linear unit has a 140 mm stroke and a millimeter scale showing 70 n~ 0 n~ 70 and
with an index on the carriage. The linear unit is driven by the various motors via a
spocket, a toothed belt and belt tensioner.
The linear unit has a pitch of 1 mm/rev, which is vital to accuracy. The speed of
travel depends on the screw pitch coupled with the motor speed. As a precaution, the
linear unit moves to an end position.
Figure 8. The generator brake mounted on the motor shaft.
Figure 9. The linear unit mounted on the support plate.