# Virtual Reality Training Application for the Condition-Based Maintenance of Induction Motors
## 4 Materials and Methods
At this level, the user interacts with a disassembled induction motor. The induction motors are composed of several parts, with the most important being the stator, rotor, shaft, bearings and frame. Individual parts can be examined closely. The objective is to identify each one of them, and to do so, the user must label them with a name, as shown in Figure 3;
* Induction motors arrangement design: This level has a twofold objective. On the one hand, the objective is to understand the connections between the motor and the integration of the gearboxes in the formation of a kinematic chain, which is also comprised of components such as generators and couplings. Secondly, the objective is to understand and to apply the synchronous speed equation, Equation (3). The user must, through self-instruction, select the motor and gear case arrangement that achieves the motor speed, \(f_{r}\), at 900 revolutions per minute (r.p.m.). For this purpose, the user has access to a large number of different motors and gear cases, as shown in Figure 4. The user has to make use of the theoretical formula, Equation (3), overprinted on the workbench, with which the problem may be solved. The arrangement is fully modifiable, so that the user can wind back the process in case of error. Figure 1: Operational learning model developed for induction motor maintenance training. Figure 4: Induction motor arrangement design level. Figure 3: Disassembly of induction motors. Figure 2: Introductory tutorial. Training Application module B approaches the simulation and identification of the operating state under the influence of induction motor faults. This module aims to represent an environment where the trainee can simulate the operating state of induction motors under the influence of different faults, so that the user can learn to identify them using MCSA current analysis. Thus, the simulation of these complicated processes can be accomplished with VR tools in an efficient and cost-effective manner. Module B was designed so that users could progress through different levels and advance towards the following goals:  
* _Introductory tutorial:_ This module incorporates new elements for interaction as the tasks that the user is expected to perform become more complex. At the following levels, the user will have to interact with user interfaces (UI) in order to select different faults to be simulated. Likewise, the user learns to use a device for the measurement of electrical signals (mainly current) as seen in Figure 5A, together with the clamp accessory that can quickly measure the current, as shown in Figure 5B;
* _Analyze induction motor faults:_ In this phase, the user can be trained in the detection of different types of faults. In front of the user on the workbench is a system composed of an induction motor and an alternator coupled to a pulley and belt system. Using the left panel, users can select the type of fault they want to learn and how to detect it. The user can choose to simulate failures of broken bars in the induction motor, misalignments and unbalances between the induction motor and the alternator, and gearing wear (uniform gradual wear on gear teeth 25%, 50% and 75%). Once the user selects a fault in the left panel, illustrated in Figure 6A, an exploded view of the object is displayed for detailed observation of the fault, as can be seen in Figure 6B. This view is immensely useful in these contexts, as these faults are normally inside a part or in an inaccessible area and are therefore not immediately visible. The whiteboard shows relevant information on the type of fault and how to detect it. By using the measurement device, the power quality of the induction motor can be analyzed, as can be seen in Figure 6C. If the user has correctly configured the measuring device, it receives the raw signal and can display it in real time.