// Numbas version: exam_results_page_options
{"name": "DC Series Generator", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "DC Series Generator", "tags": [], "metadata": {"description": "", "licence": "None specified"}, "statement": "<p>In testing, a separately excited DC machine, operating at a speed of $\\var{Ntest}\\ rpm$, produces $\\var{Vtest}\\ V$ with an open circuit armature, when operated at a fixed field current of $\\var{IF}\\ A$.</p>\n<p>Its intrinsic resistances are:</p>\n<p>Field Resistance:&nbsp;$R_F = \\var{RF}\\ \\Omega&nbsp;$</p>\n<p>Armature Resistance:&nbsp;$R_A = \\var{RA}\\&nbsp; \\Omega&nbsp;$&nbsp;</p>\n<p>The machine is then connected as a series generator to supply a load with a current of&nbsp;$\\var{IF}\\ A$ when running at a speed of $\\var{N}\\ rpm$ .</p>", "advice": "", "rulesets": {}, "extensions": [], "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"Ntest": {"name": "Ntest", "group": "Test Data", "definition": "random(1000 .. 2000#100)", "description": "", "templateType": "randrange", "can_override": false}, "RF": {"name": "RF", "group": "Operation", "definition": "random(10 .. 50#5)", "description": "", "templateType": "randrange", "can_override": false}, "RA": {"name": "RA", "group": "Operation", "definition": "random(1 .. 10#1)", "description": "", "templateType": "randrange", "can_override": false}, "VL": {"name": "VL", "group": "Operation", "definition": "random(100 .. 500#1)", "description": "", "templateType": "randrange", "can_override": false}, "IF": {"name": "IF", "group": "Operation", "definition": "random(1 .. 10#1)", "description": "", "templateType": "randrange", "can_override": false}, "N": {"name": "N", "group": "Operation", "definition": "round(60*omega/(2*pi))", "description": "", "templateType": "anything", "can_override": false}, "magnetism": {"name": "magnetism", "group": "Test Data", "definition": "Vtest/(2*pi*Ntest/60)", "description": "", "templateType": "anything", "can_override": false}, "omega": {"name": "omega", "group": "Operation", "definition": "ea/magnetism", "description": "", "templateType": "anything", "can_override": false}, "T": {"name": "T", "group": "Operation", "definition": "magnetism*IF", "description": "", "templateType": "anything", "can_override": false}, "ea": {"name": "ea", "group": "Operation", "definition": "VL + IF*(RA+RF)", "description": "", "templateType": "anything", "can_override": false}, "Vtest": {"name": "Vtest", "group": "Test Data", "definition": "random(100 .. 500#50)", "description": "", "templateType": "randrange", "can_override": false}, "RL": {"name": "RL", "group": "Operation", "definition": "VL/IF", "description": "", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "RL > 0", "maxRuns": "1000"}, "ungrouped_variables": [], "variable_groups": [{"name": "Test Data", "variables": ["Ntest", "Vtest", "magnetism"]}, {"name": "Operation", "variables": ["IF", "RF", "RA", "VL", "T", "ea", "omega", "N", "RL"]}], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "gapfill", "useCustomName": true, "customName": "Magnetism", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the magnetism on the machine?</p>\n<p>$k_a \\phi = $ [[0]]</p>", "stepsPenalty": 0, "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<ul>\n<li>Convert the testing speed from $N$ in rpm to $\\omega$ in rad/s.</li>\n<li>Fill all testing values into $e_a=k_a\\phi\\omega$ to get the magnetism, $k_a\\phi$ at the given current.</li>\n</ul>"}], "gaps": [{"type": "numberentry", "useCustomName": true, "customName": "Magnetism", "marks": "10", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "minValue": "magnetism*0.99", "maxValue": "magnetism*1.01", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": true, "customName": "Torque", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the torque on the shaft?</p>\n<p>$T$ =&nbsp;[[0]] $ Nm $</p>", "stepsPenalty": 0, "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<ul>\n<li>Find the torque from $T=k_a\\phi I_A$.</li>\n</ul>"}], "gaps": [{"type": "numberentry", "useCustomName": true, "customName": "Torque", "marks": "5", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "minValue": "T*0.99", "maxValue": "T*1.01", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "sortAnswers": false}, {"type": "gapfill", "useCustomName": true, "customName": "Voltage", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<p>What is the output voltage to the load?</p>\n<p>$V_L$&nbsp;=&nbsp;[[0]] $ V $</p>\n<p>What is the load resistance?</p>\n<p>$R_L$ =&nbsp;[[1]] $\\Omega$</p>", "stepsPenalty": 0, "steps": [{"type": "information", "useCustomName": false, "customName": "", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "<ul>\n<li>Calcuate the voltage, $e_a$, from $e_a=k_a\\phi \\omega$.</li>\n<li>Find the output voltage 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