Among three-phase power supply the synchronous machines are widely used and they called so because the speed of the rotor of these machines are the same as the rotating magnetic field. They are commonly used as generators especially for large power systems, such as turbine and hydroelectric generators in the grid power supply. Because the rotor speed is proportional to the frequency of excitation,synchronous motors can be used in situations where constant speed drive is required. Since the reactive power generated by a synchronous machine can be adjusted by controlling the magnitude of the rotor field current, unloaded synchronous machines are also often installed in power systems solely for power factor correction or for control of reactive kVA flow. Their construction is almost similar to that a three-phase induction motor except the fact that the rotor is given DC supply.
....
Three-Phase Synchronous Machine with smooth inductor and three-phase stator armature winding for operation either as alternator or synchronous motor.
Power: 1 kVA
Current: 2.6/1.5 A /Y
Voltage: 220/380 V/Y
Rated speed: 1500 rpm, 50 Hz
Rated speed: 1800 rpm, 60 Hz
The Synchronous Machine is designed to operate as a motor or as an alternator. The rotor works as a square cage when starting and stopping. The three-stator windings are brought out to 4-mm separated terminals on the housing, so that they may be connected in wye or delta. The Synchronous Machine runs at constant speed independently of the load. The synchronous speed directly depends on the current frequency and on the number of motor poles. The trainer is also provided with supply terminals, a rheostat for control over the excitation current and a protective circuit breaker in the rotor circuit. Specifications and/or diagrams are silk-screened on the back of a clear-plastic front panel for ease of identification. The main characteristic of a Synchronous Machine is the possibility to change the power factor. Its stator is connected to an AC power supply and its rotor must be linked to a AC/DC rectifying unit. The trainer is protected by a either a diode or thermal-magnetic circuit breaker. Included in the Rotating Machines Trainer for 1/3 hp - 250 W. Requires a 120V 60Hz circuit.
....
Refurbishing Work
Console Mechanical Reassembling
Console reassembling
Clear rear panel changing
Assembling and mechanical adjustment of motor
Repair and/or replacement of casters and couplings
Working table replacement
Complete Console Disassembling
Mechanical repair of housing if required
Sand blasting and painting
Complete Testing And Verifying
Coupling verifying on both sides of machine
Electrical testing w/o load
Inspection report and quality control.
Complete Motor Disassembling
Motor inspection
Repair and replacement of brush assembly if required
External painting
Bearing replacement
Electrical Reassembling And Rewiring
Electrical part replacement
Front panel replacement
Rewiring.
