{"id":45942,"date":"2024-04-15T22:05:15","date_gmt":"2024-04-15T22:05:15","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=45942"},"modified":"2024-04-15T22:05:15","modified_gmt":"2024-04-15T22:05:15","slug":"to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/","title":{"rendered":"To avoid formation of grooves in the commutator of a D.C. machine"},"content":{"rendered":"<p>\r\n    <!-- Check if it's an AMP page -->\r\n            <!-- Non-AMP version -->\r\n        <div class=\"mcq-container\" data-quiz-id=\"quizState_6a974644b503d\">\r\n                                            <div class=\"option\" data-option-key=\"option1\" data-is-correct=\"true\">\r\n                    The brushes of opposite polarity should track each other                <\/div>\r\n                                            <div class=\"option\" data-option-key=\"option2\" data-is-correct=\"false\">\r\n                    The brushes of same polarity should track each other                <\/div>\r\n                                            <div class=\"option\" data-option-key=\"option3\" data-is-correct=\"false\">\r\n                    machine A. The brushes of opposite polarity should track each other B. The brushes of same polarity should track each other C. Brush position has no effect on the commutator grooving                <\/div>\r\n                                            <div class=\"option\" data-option-key=\"option4\" data-is-correct=\"false\">\r\n                    All of the above                <\/div>\r\n                            \r\n            <!-- Feedback messages for non-AMP -->\r\n            <div class=\"feedback\" data-feedback=\"wrong\">Answer is Right!<\/div>\r\n            <div class=\"feedback\" data-feedback=\"right\">Answer is Wrong!<\/div>\r\n        <\/div>\r\n\r\n        <script>\r\n        document.addEventListener('DOMContentLoaded', function () {\r\n            var containers = document.querySelectorAll('.mcq-container');\r\n\r\n            containers.forEach(function(container) {\r\n                var options = container.querySelectorAll('.option');\r\n                var feedbackSelect = container.querySelector('[data-feedback=\"select\"]');\r\n                var feedbackWrong = container.querySelector('[data-feedback=\"wrong\"]');\r\n                var feedbackRight = container.querySelector('[data-feedback=\"right\"]');\r\n\r\n                options.forEach(function(option) {\r\n                    option.addEventListener('click', function() {\r\n                        var selectedOption = option.getAttribute('data-option-key');\r\n                        var isCorrect = option.getAttribute('data-is-correct') === 'true';\r\n\r\n                        \/\/ Remove previous selections\r\n                        options.forEach(function(opt) {\r\n                            opt.classList.remove('correct', 'incorrect');\r\n                        });\r\n\r\n                        \/\/ Add the correct\/incorrect class\r\n                        if (isCorrect) {\r\n                            option.classList.add('correct');\r\n                            feedbackRight.hidden = false;\r\n                            feedbackWrong.hidden = true;\r\n                        } else {\r\n                            option.classList.add('incorrect');\r\n                            feedbackRight.hidden = true;\r\n                            feedbackWrong.hidden = false;\r\n                        }\r\n\r\n                        \/\/ Hide select feedback\r\n                        feedbackSelect.hidden = true;\r\n                    });\r\n                });\r\n            });\r\n        });\r\n        <\/script>\r\n    \r\n    <!--more--><\/p>\n<p>The correct answer is: A. The brushes of opposite polarity should track each other.<\/p>\n<p>The brushes of a DC machine are two or more conducting blocks that make contact with the commutator. The <div class=\"telegram-channel-container\">\r\n        <a href=\"https:\/\/t.me\/pscnotes2025\" target=\"_blank\" class=\"telegram-channel-button\">\r\n            <span class=\"telegram-icon\">\r\n                <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 496 512\">\r\n                    <path fill=\"white\" d=\"M248,8C111,8,0,119,0,256s111,248,248,248s248-111,248-248S385,8,248,8z M362,177L320,367c-3,14-10,18-20,14l-56-41l-27,26 c-3,3-5,5-10,5l4-63L323,196c5-5-1-7-8-3l-98,62l-42-13c-9-3-10-9,2-14l162-63C351,160,365,164,362,177z\"\/>\r\n                <\/svg>\r\n            <\/span>\r\n            Join Our Telegram Channel\r\n        <\/a>\r\n    <\/div> commutator is a cylindrical metal ring that is divided into segments. The brushes are held in place by brush holders and are pressed against the commutator by springs.<\/p>\n<p>The brushes conduct current from the external circuit to the rotor windings. The current flows through the rotor windings and creates a magnetic field. The magnetic field interacts with the stator field to produce torque.<\/p>\n<p>The brushes must track each other to ensure that the current flows evenly to the rotor windings. If the brushes do not track each other, the commutator will groove.<\/p>\n<p>Grooving of the commutator can cause a number of problems, including:<\/p>\n<ul>\n<li>Increased resistance in the rotor windings<\/li>\n<li>Decreased efficiency of the machine<\/li>\n<li>Increased sparking at the brushes<\/li>\n<li>Damage to the commutator<\/li>\n<\/ul>\n<p>To avoid grooving of the commutator, the brushes must be kept clean and free of debris. The brush holders should be adjusted so that the brushes are in good contact with the commutator. The commutator should be inspected regularly and resurfaced if necessary.<\/p>\n<p>The following are the incorrect answers and their explanations:<\/p>\n<p>B. The brushes of same polarity should track each other.<\/p>\n<p>This is incorrect because the brushes of opposite polarity should track each other. The brushes of same polarity will repel each other and will not <div class=\"youtube-subscribe-container\">\r\n        <a href=\"https:\/\/www.youtube.com\/channel\/UCNHT8lW-JmLC68rjBfZhdkg?sub_confirmation=1\" target=\"_blank\" class=\"youtube-subscribe-button\">\r\n            <span class=\"youtube-icon\">\r\n                <svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 576 512\">\r\n                    <path d=\"M549.7 124.1c-6.3-23.7-24.8-42.3-48.3-48.6C458.8 64 288 64 288 64S117.2 64 74.6 75.5c-23.5 6.3-42 24.9-48.3 48.6-11.4 42.9-11.4 132.3-11.4 132.3s0 89.4 11.4 132.3c6.3 23.7 24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z\"\/>\r\n                <\/svg>\r\n            <\/span>\r\n            Subscribe on YouTube\r\n        <\/a>\r\n    <\/div> track properly.<\/p>\n<p>C. Brush position has no effect on the commutator grooving.<\/p>\n<p>This is incorrect because the brush position has a significant effect on the commutator grooving. If the brushes are not in good contact with the commutator, the commutator will groove.<\/p>\n<p>D. All of the above.<\/p>\n<p>This is incorrect because only option A is correct.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Subscribe on YouTube<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[742],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>To avoid formation of grooves in the commutator of a D.C. machine<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"To avoid formation of grooves in the commutator of a D.C. machine\" \/>\n<meta property=\"og:description\" content=\"Subscribe on YouTube\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2024-04-15T22:05:15+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"To avoid formation of grooves in the commutator of a D.C. machine","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/","og_locale":"en_US","og_type":"article","og_title":"To avoid formation of grooves in the commutator of a D.C. machine","og_description":"Subscribe on YouTube","og_url":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2024-04-15T22:05:15+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/","url":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/","name":"To avoid formation of grooves in the commutator of a D.C. machine","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2024-04-15T22:05:15+00:00","dateModified":"2024-04-15T22:05:15+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/to-avoid-formation-of-grooves-in-the-commutator-of-a-d-c-machine\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"mcq","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/mcq\/"},{"@type":"ListItem","position":3,"name":"Electrical engineering","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/mcq\/electrical-engineering\/"},{"@type":"ListItem","position":4,"name":"D.c. 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