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 with emphasis on those devices used for equipment protection and personnel safety. A brief description of the 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 a 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 five kW, 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. The prime mover for the experimental generator is a 7.5 hp, four-pole synchronous motor.
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.
Voltage and current probes, data-acquisition systems, digital multimeters, oscilloscopes, tachometers, power supplies, etc.