The Mine Electrical Systems Laboratory is a 527-square-foot facility dedicated primarily to research of electrical engineering applications in the mining industry. There is some limited instructional use which consists of the demonstration of operating principles of electrical and electronic devices commonly used in the mining industry and safety aspects of mine electrical systems. A brief description of equipment in the Mine Electrical Systems Laboratory is given below.
Universal Laboratory Machine
The Universal Laboratory machine (ULM) is a two-pole, uniform airgap universal machine directly coupled to a swinging frame DC dynamometer. The stator windings of the ULM are terminated on a panel at the front of the machine. This terminal panel makes it possible to form a large variety of phase and field windings by connecting the individual coils in different configurations. The dynamometer can be used as separately excited generator or as a field-controlled shunt motor.
Experimental Synchronous Machine:
The experimental synchronous machine is used for investigating electrical deterioration detection in three-phase synchronous generators. The machine is a 5kW, 1800 rpm synchronous generator with unique modifications to permit simulation of armature and field winding deterioration. The armature circuit has been modified to include 45 electrical taps connected at various points of the winding that are brought out to terminal strips for access. Insulation deterioration is simulated by creating leakage paths in the winding by connecting these taps together at the terminal strips. The types of deterioration that can be simulated include turn-to-turn, coil-to-coil, and phase-to-phase. The field circuit has also been modified to permit access to the field winding at nine different points.
Ground Fault Protection Demonstrator:
The Ground Fault Protection Demonstrator is a fully functional ground fault protection system for both three-phase and single-phase systems. The demonstrator includes a three-pole circuit breaker equipped with a shunt trip device, current transformers, an electronic ground fault relay, instrument transformer, ammeters and a variable impedance fault. The demonstrator is used for demonstrating zero-sequence relaying, direct relaying, potential relaying, the effect of parallel paths and so forth.
AC Motor Controller:
The AC motor controller includes devices necessary for demonstrating full-voltage starting, reduced-voltage starting, reversing and overload protection of three-phase induction motors.
DC Motor Controller:
The DC motor controller includes devices necessary for demonstrating full and reduced voltage starting, adjustable-speed operation, dynamic braking, overload and field-failure protection.
Motor-Generator Set:
The Motor-Generator set is composed of a 7.5 HP four-pole synchronous motor coupled to a 5.0 kW four-pole synchronous generator. The synchronous generator has been custom-built to provide access to 45 individual points within the armature winding and 9 different points in the field winding.
Programmable Logic Controllers:
PLCs consist of two Allen Bradley SLC 5/03 programmable logic controllers, each with 16 inputs and 16 outputs. Five copies of RSLogix 500 ™ ladder logic programming software are available for the development of logical statements that can be downloaded to the SLC 5/03.
Miscellaneous:
Voltage and current probes, digital multimeters, oscilloscope, tachometers, power supplies, motors, generators, transformers, control circuit panels, etc.