{"id":86,"date":"2020-01-13T14:43:26","date_gmt":"2020-01-13T19:43:26","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/basicmotorcontrol\/?post_type=chapter&p=86"},"modified":"2020-08-14T19:02:43","modified_gmt":"2020-08-14T23:02:43","slug":"three-wire-with-pilot-lights","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/basicmotorcontrol\/chapter\/three-wire-with-pilot-lights\/","title":{"raw":"Three-Wire Circuit With Pilot Lights","rendered":"Three-Wire Circuit With Pilot Lights"},"content":{"raw":"[caption id=\"attachment_210\" align=\"aligncenter\" width=\"1024\"]\"\" Three-wire control circuit with pilot lights[\/caption]\r\n\r\nMotors are often installed in loud environments or at remote locations, and so simply relying on the sound of a running motor to tell an operator its status is unreliable. To aid with this, we can connect [pb_glossary id=\"850\"]pilot lights<\/strong>[\/pb_glossary] in our [pb_glossary id=\"796\"]control circuit<\/strong>[\/pb_glossary] to indicate the running status of a motor. Pilot lights that are installed in the control circuit in [pb_glossary id=\"852\"]parallel<\/strong>[\/pb_glossary] with the motor starter will be energized when the motor is energized. These are often referred to as motor running lights.\r\n\r\nPilot lights must NEVER be installed in [pb_glossary id=\"977\"]series<\/strong>[\/pb_glossary] with motor starters; the motor starter might not have enough [pb_glossary id=\"718\"]voltage<\/strong>[\/pb_glossary] to pull in, and if the filament in the pilot light burns out, it will create an open in series with the rest of the circuit.\r\n\r\nMotor starters often come with [pb_glossary id=\"854\"]auxiliary contacts<\/strong>[\/pb_glossary] beyond the [pb_glossary id=\"742\"]normally open<\/strong>[\/pb_glossary] [pb_glossary id=\"853\"]2-3 holding contacts<\/strong>[\/pb_glossary], and if not, many starters can have additional auxiliary contacts added to them.\r\n\r\nIf a motor starter has a set of [pb_glossary id=\"744\"]normally closed contacts<\/strong>[\/pb_glossary] these can be wired in series with a pilot light. As long as the motor starter is not energized, the contacts will remain closed and the light will be on. This can indicate to an operator that a motor is in the off or de-energized condition.","rendered":"
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Three-wire control circuit with pilot lights<\/figcaption><\/figure>\n

Motors are often installed in loud environments or at remote locations, and so simply relying on the sound of a running motor to tell an operator its status is unreliable. To aid with this, we can connect pilot lights<\/strong><\/a> in our control circuit<\/strong><\/a> to indicate the running status of a motor. Pilot lights that are installed in the control circuit in parallel<\/strong><\/a> with the motor starter will be energized when the motor is energized. These are often referred to as motor running lights.<\/p>\n

Pilot lights must NEVER be installed in series<\/strong><\/a> with motor starters; the motor starter might not have enough voltage<\/strong><\/a> to pull in, and if the filament in the pilot light burns out, it will create an open in series with the rest of the circuit.<\/p>\n

Motor starters often come with auxiliary contacts<\/strong><\/a> beyond the normally open<\/strong><\/a> 2-3 holding contacts<\/strong><\/a>, and if not, many starters can have additional auxiliary contacts added to them.<\/p>\n

If a motor starter has a set of normally closed contacts<\/strong><\/a> these can be wired in series with a pilot light. As long as the motor starter is not energized, the contacts will remain closed and the light will be on. This can indicate to an operator that a motor is in the off or de-energized condition.<\/p>\n

definition<\/span>