{"id":83,"date":"2020-01-13T13:36:38","date_gmt":"2020-01-13T18:36:38","guid":{"rendered":"https:\/\/opentextbc.ca\/basicmotorcontrol\/chapter\/control-relays\/"},"modified":"2023-03-02T11:55:24","modified_gmt":"2023-03-02T16:55:24","slug":"control-relays","status":"publish","type":"chapter","link":"https:\/\/opentextbc.ca\/basicmotorcontrol\/chapter\/control-relays\/","title":{"raw":"Control Relays","rendered":"Control Relays"},"content":{"raw":"[pb_glossary id=\"262\"]Control relays[\/pb_glossary] are magnetic devices that are used to remotely switch loads. They are functionally identical to a magnetic [pb_glossary id=\"227\"]motor starter[\/pb_glossary], save that control relays lack [pb_glossary id=\"233\"]horsepower-rated contacts[\/pb_glossary] and built-in [pb_glossary id=\"208\"]overload[\/pb_glossary] protection.\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"232\"]<img src=\"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-content\/uploads\/sites\/314\/2020\/01\/Control-Relay-e1579722791916.png\" alt=\"\" width=\"232\" height=\"303\" \/> Control relay.[\/caption]\r\n\r\nSince magnetic-motor starters are limited in the number of [pb_glossary id=\"267\"]auxiliary electrical contacts[\/pb_glossary], control relays are used where additional contacts are required to switch low-level current loads such as [pb_glossary id=\"270\"]pilot lights[\/pb_glossary], motor starters, or other relays.\r\n\r\nSome control relays are the latching-type relay, in that after energizing the coil, the relay contacts remain mechanically latched in the closed position, even after power is removed from the coil. To open the relay contacts, the coil requires the momentary energization of a second coil to unlatch the coil.\r\n\r\nThe advantage of this type of relay is that it is not necessary to keep the coil continuously energized, which results in quieter operation and less current drawn from the source.\r\n\r\nhttps:\/\/media.bccampus.ca\/id\/0_78f45o7j?width=608&amp;height=402&amp;playerId=23449753","rendered":"<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_83_262\">Control relays<\/a> are magnetic devices that are used to remotely switch loads. They are functionally identical to a magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_83_227\">motor starter<\/a>, save that control relays lack <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_83_233\">horsepower-rated contacts<\/a> and built-in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_83_208\">overload<\/a> protection.<\/p>\n<figure style=\"width: 232px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-content\/uploads\/sites\/314\/2020\/01\/Control-Relay-e1579722791916.png\" alt=\"\" width=\"232\" height=\"303\" \/><figcaption class=\"wp-caption-text\">Control relay.<\/figcaption><\/figure>\n<p>Since magnetic-motor starters are limited in the number of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_83_267\">auxiliary electrical contacts<\/a>, control relays are used where additional contacts are required to switch low-level current loads such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_83_270\">pilot lights<\/a>, motor starters, or other relays.<\/p>\n<p>Some control relays are the latching-type relay, in that after energizing the coil, the relay contacts remain mechanically latched in the closed position, even after power is removed from the coil. To open the relay contacts, the coil requires the momentary energization of a second coil to unlatch the coil.<\/p>\n<p>The advantage of this type of relay is that it is not necessary to keep the coil continuously energized, which results in quieter operation and less current drawn from the source.<\/p>\n<p><iframe loading=\"lazy\" id=\"kaltura_player\" title=\"Electric Relays 101\" src=\"https:\/\/api.ca.kaltura.com\/p\/148\/sp\/14800\/embedIframeJs\/uiconf_id\/23449753\/partner_id\/148?iframeembed=true&#38;playerId=kaltura_player&#38;entry_id=0_78f45o7j&#38;flashvars[leadWithHTML5]=true&#38;flashvars[streamerType]=auto&#38;flashvars[localizationCode]=en&#38;flashvars[sideBarContainer.plugin]=true&#38;flashvars[sideBarContainer.position]=left&#38;flashvars[sideBarContainer.clickToClose]=true&#38;flashvars[chapters.plugin]=true&#38;flashvars[chapters.layout]=vertical&#38;flashvars[chapters.thumbnailRotator]=false&#38;flashvars[streamSelector.plugin]=true&#38;flashvars[EmbedPlayer.SpinnerTarget]=videoHolder&#38;flashvars[dualScreen.plugin]=true&#38;flashvars[Kaltura.addCrossoriginToIframe]=true&#38;wid=0_uzgntobd\" width=\"608\" height=\"402\" allowfullscreen=\"allowfullscreen\" sandbox=\"allow-downloads allow-forms allow-same-origin allow-scripts allow-top-navigation allow-pointer-lock allow-popups allow-modals allow-orientation-lock allow-popups-to-escape-sandbox allow-presentation allow-top-navigation-by-user-activation\" frameborder=\"0\"><\/iframe><\/p>\n<div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_83_262\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_83_262\"><div tabindex=\"-1\"><p>Used when additional auxiliary contacts are needed in a control circuit, a control relay is a magnetic contactor which is <strong>not<\/strong> designed for the energization of motors, and <strong>does not<\/strong> have built in overload protection.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_83_227\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_83_227\"><div tabindex=\"-1\"><p>A device that controls the flow of electrical power to a motor. It is designed to safely start and stop a motor, and provide <strong>overload protection<\/strong>.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_83_233\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_83_233\"><div tabindex=\"-1\"><p>A set of contacts that has been designed to make or break the flow of current to a motor and can handle loads up to a specified amount of horsepower at a specific voltage. The size of contacts are determined by the size of the motor they are controlling.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_83_208\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_83_208\"><div tabindex=\"-1\"><p>A moderate and gradual rise in the value of current over a relatively long period of time that is caused by excessive amounts of current drawn by a motor due to too much load being put on the motor.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_83_267\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_83_267\"><div tabindex=\"-1\"><p>Contacts on a magnetic starter that are not Horsepower rated. Can come as either normally-open or normally-closed and can be used as maintaining contacts, electrical interlocks or control for pilot lights.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_83_270\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_83_270\"><div tabindex=\"-1\"><p>A small lamp connected in the control circuit to indicate the status of a motor or other situation.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":90,"menu_order":6,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-83","chapter","type-chapter","status-publish","hentry"],"part":59,"_links":{"self":[{"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/chapters\/83","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/wp\/v2\/users\/90"}],"version-history":[{"count":4,"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/chapters\/83\/revisions"}],"predecessor-version":[{"id":441,"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/chapters\/83\/revisions\/441"}],"part":[{"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/parts\/59"}],"metadata":[{"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/chapters\/83\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/wp\/v2\/media?parent=83"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/pressbooks\/v2\/chapter-type?post=83"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/wp\/v2\/contributor?post=83"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/opentextbc.ca\/basicmotorcontrol\/wp-json\/wp\/v2\/license?post=83"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}