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المحتوى المقدم من Bryan Orr. يتم تحميل جميع محتويات البودكاست بما في ذلك الحلقات والرسومات وأوصاف البودكاست وتقديمها مباشرة بواسطة Bryan Orr أو شريك منصة البودكاست الخاص بهم. إذا كنت تعتقد أن شخصًا ما يستخدم عملك المحمي بحقوق الطبع والنشر دون إذنك، فيمكنك اتباع العملية الموضحة هنا https://ar.player.fm/legal.
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Motor Protection Types - Short #192

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Manage episode 412828132 series 1264891
المحتوى المقدم من Bryan Orr. يتم تحميل جميع محتويات البودكاست بما في ذلك الحلقات والرسومات وأوصاف البودكاست وتقديمها مباشرة بواسطة Bryan Orr أو شريك منصة البودكاست الخاص بهم. إذا كنت تعتقد أن شخصًا ما يستخدم عملك المحمي بحقوق الطبع والنشر دون إذنك، فيمكنك اتباع العملية الموضحة هنا https://ar.player.fm/legal.

In this short podcast episode, Bryan talks about motor protection types, including overloads.

The most common overload we see in residential HVAC is a built-in thermal overload, which is usually a bimetallic disk that flexes in response to heat (such as from a locked condition, electrical problem, or simply running hot) and opens the circuit. The two metals have different expansion and contraction rates, which causes the flexing; they will return to their original position once the motor cools down. In some cases, these can fail when they open and close too often; they are not designed for switching duty. Many circuit breakers have a similar thermal design and may be prone to nuisance tripping in the summer.

A lot of commercial motors rely on external overloads; some are even built into the electrical box rather than the compressor. These external magnetic overloads are often integrated into the contactor, which turns the motor on and off; this type of contactor is called a starter. These starters may have adjustable overload settings based on current, not just temperature (which may also respond to nuisance sources of heat and require a cooldown period). Some circuit breakers also trip magnetically and are less likely to be affected by temperature.

Thermistor-based overloads usually consist of a PTC (positive temperature coefficient) resistor; as temperature goes up, resistance goes up, which can take a motor winding out of the circuit. NTCs are in separate parallel circuits with relays; as the resistance decreases, it pulls in a coil that opens the circuit.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

  continue reading

691 حلقات

Artwork
iconمشاركة
 
Manage episode 412828132 series 1264891
المحتوى المقدم من Bryan Orr. يتم تحميل جميع محتويات البودكاست بما في ذلك الحلقات والرسومات وأوصاف البودكاست وتقديمها مباشرة بواسطة Bryan Orr أو شريك منصة البودكاست الخاص بهم. إذا كنت تعتقد أن شخصًا ما يستخدم عملك المحمي بحقوق الطبع والنشر دون إذنك، فيمكنك اتباع العملية الموضحة هنا https://ar.player.fm/legal.

In this short podcast episode, Bryan talks about motor protection types, including overloads.

The most common overload we see in residential HVAC is a built-in thermal overload, which is usually a bimetallic disk that flexes in response to heat (such as from a locked condition, electrical problem, or simply running hot) and opens the circuit. The two metals have different expansion and contraction rates, which causes the flexing; they will return to their original position once the motor cools down. In some cases, these can fail when they open and close too often; they are not designed for switching duty. Many circuit breakers have a similar thermal design and may be prone to nuisance tripping in the summer.

A lot of commercial motors rely on external overloads; some are even built into the electrical box rather than the compressor. These external magnetic overloads are often integrated into the contactor, which turns the motor on and off; this type of contactor is called a starter. These starters may have adjustable overload settings based on current, not just temperature (which may also respond to nuisance sources of heat and require a cooldown period). Some circuit breakers also trip magnetically and are less likely to be affected by temperature.

Thermistor-based overloads usually consist of a PTC (positive temperature coefficient) resistor; as temperature goes up, resistance goes up, which can take a motor winding out of the circuit. NTCs are in separate parallel circuits with relays; as the resistance decreases, it pulls in a coil that opens the circuit.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”

Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.

Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

  continue reading

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