A single sheet of white paper, likely an A4 document, lies on a dark, textured surface in Galabovo, Bulgaria

A single sheet of white paper, likely an A4 document, lies on a dark, textured surface in Galabovo, Bulgaria. The paper exhibits minor creasing and some faint speckled artifacts, suggesting it is a printout or photocopy. The content is predominantly in Bulgarian, featuring mathematical formulas and an electrical circuit diagram. The upper section of the document presents formulas related to electrical engineering concepts, including: * "Фактора на мощността - cos φ" (Power factor - cos φ) with the formula `cos φ = P1 / (√3 . U1 . I1)`. * A partially visible description leading to "P2" (output useful power on the engine shaft). * The formula `M2 = (60 . P2) / (2 . π . n)`. * An approximation formula `P2 ≈ 0.1047 . n . M2`. * "КПД" (Efficiency) with the formula `η = (P2 / P1) . 100 %`. Below this, a section titled "II. Използвани схеми" (II. Used schemes/diagrams) introduces an "Електрическа схема" (Electrical diagram). This diagram depicts a three-phase electrical circuit. It includes three input lines (U1, V1, W1), each indicating 24V, connected to two wattmeters (WP1, WP2), an ammeter (A), and a voltmeter (V). These are wired to a series of inductive coils and resistors, representing a load connected to a three-phase motor symbol (M 3~). To the right of the motor, a separate circuit shows a component labeled "B," an ammeter (A!), and a power source indicating 9x40V. The bottom section of the document partially displays the heading "II. Резултати от изследванията и изчисления" (II. Results of the research and calculations). The paper is positioned on a dark gray or black surface with a repeating pattern of circular depressions, consistent with a rubber mat or a specialized workbench. The lighting is even, suggesting an indoor environment. No individuals or active interactions are depicted in the image.