10125 Ing Vers 2012 - Lab Openlab

 STARTING AND SYNCHRONIZATION RHEOSTAT FOR SYNCHRONIZABLE ASYNCHRONOUS MOTOR DL 10125

 Openlab Laboratory

DL 10125

CONTENTS

1. GENERAL NOTES

Page

3

2. MECHANICAL FEATURES

Page

3

3. LAYOUT OF CONTROLS AND SIGNALLING

Page

3

4. POWER SUPPLY

Page

4

5. D.C. POWER SUPPLY UNIT

Page

4

6. RHEOSTATIC STARTING

Page

5

7. RHEOSTATIC STARTING AND MOTOR SYNCHRONIZATION

Page

6

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DL 10125

1. GENERAL NOTES The DL 10125 unit is suited for starting the synchronizable asynchronous motor and for its operation as alternator when motor-driven.

2. MECHANICAL FEATURES The unit is built in a closed fire-varnished metal cabinet. On the front side the different control and connection devices are arranged. On the rear side the connector is available for the connection to the mains. A clear synoptic diagram, printed by silk-screening process, allows an easy operation of the unit.

3. LAYOUT OF CONTROLS AND SIGNALLING

DE LORENZO 40

R3A

60

K

R2A

M 3

L M F1

20

80

KL MS 3

R1A

M

power on

F2

K

S1

S2

S1: S2: VAR 1: M1-M2-M3: M4-M5: F1:

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M

M1 M2 M3

0

100% F1

F2

VAR1 F1 M4 M5

Main switch with pilot lamp Starting and synchronization switch Voltage variator for d.c. output Motor connection terminals D.C. Output terminals Protection fuse for D.C. Output

3

DL 10125

4. POWER SUPPLY The unit is designed to be supplied from the 220 V, 50 ÷ 60 Hz single-phase mains, through main tray connector with built-in fuse and power cord.

5. D.C. POWER SUPPLY UNIT When the unit is supplied from 220V mains, the D.C. output M4-M5 is operated through switch S1 with built-in pilot lamp and adjusted through knob VAR 1. -Adjustment range: 0 to approximately 8V. The D.C. output is insulated from mains and protected by fuse F1.

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DL 10125 6. RHEOSTATIC STARTING

The starting of the wound rotor three-phase asynchronous motor through the starting rheostat allows high torque values to be obtained with very small currents.

DE LORENZO

NOTE: It is not necessary to supply DL 10125 unit from mains. Set the switch S2 of DL 10125 unit to position R1A of maximum resistance and connect the terminals M1-M2-M3 to the rotor windings of the motor, following the labelling. Set-up and connect the stator windings of the motor to the mains (Y or Δ connection),then supply power to the motor, that will start to rotate. Now set the switch S2 to positions "R2A" and "R3A". As soon as the rheostat resistance is decreased, the rotating speed increases. Finally, short-circuit the rotor brushes by setting the switch S2 to position "4". The motor will rotate at the rated speed, close to the synchronism speed.

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DL 10125 7. RHEOSTATIC STARTING AND MOTOR SYNCHRONIZATION

The synchronization of the asynchronous motor can be performed by converting the rotor into the un notched inductor of a synchronous machine. For this purpose, two rings are short-circuited, while the third ring is connected to the other two through a D.C. source.

DE LORENZO

Refers to experiment N°20 and N°21 of the first volume DL 10280 - Electrical Motors and to experiment N°40,41,42,43,44 and 45 of the second volume DL 10280 - Electrical Generators and Annex.

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© 1996 - 2013 DE LORENZO SPA - Printed in Italy - All right reserved DE LORENZO SPA V.le Romagna, 20 - 20089 Rozzano (MI) Italy Tel. ++39 02 8254551 - Fax ++39 02 8255181 E-mail: [email protected] Web sites: www.delorenzoglobal.com - www.technical-education.it www.delorenzoenergy.com