STARTING AND SYNCHRONIZATION RHEOSTA RHEOST AT FOR F OR SYNCHRONIZABL S YNCHRONIZABLE E 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
VA R1 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 a nd 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. 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 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. 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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