Maximum lifespan and reliability: What you need to know about protecting your motors.
What is the main advantage of a thermally protected motor in continuous operation?
The main advantage is the avoidance of costly motor failures due to overheating. This leads to a significant reduction in unplanned downtimes (by about 15%) and a substantial increase in the mean time between failures (MTBF) of more than 20%.
How do PTC thermistors protect a motor in continuous operation?
PTC thermistors (NTC) are directly placed in the motor winding and dramatically increase their resistance in case of overheating. This signals the protective device to shut down the motor before critical temperatures are reached and damage occurs..
When is a manual reset of the thermal protection preferable to an automatic one?
A manual reset, typical for PTO switches (bimetal), is preferable when an unexpected restart of the motor would pose a safety risk , for example, with conveyor belts. It enforces a root cause analysis before restarting and thus increases operational safety.
Why is the correct selection and installation of thermal protection so important?
A mismatch or incorrect installation can negate the protective effect, lead to unnecessary shutdowns, or insufficiently protect the motor. This can significantly shorten the lifespan of the motor (by up to 50%) and jeopardize the safety of the facility.
What distinguishes a motor protection switch (MSS) from a motor protection relay (MSR) in the context of continuous operation?
An MSS combines overload and short circuit protection and directly switches the main circuit. An MSR controls external contactors and requires separate short circuit protection but often offers more flexibility in adjusting the protective characteristics, which can be advantageous for continuous operation applications.
Can electronic overload relays improve reliability in continuous operation?
Yes, electronic overload relays offer adjustable trip classes and often provide a more accurate detection of motor load. This can significantly reduce false tripping during high inrush currents or variable loads by up to 70% thereby increasing plant availability.
Which standards are particularly relevant for thermally protected motors?
Important standards include DIN 44081 for PTC sensors and the DIN EN 60947 series (especially -4-1) for motor protection switches and relays. For use in explosive areas, the additional DIN EN 60079-14 must be observed.
How does effective thermal protection contribute to improving overall equipment effectiveness (OEE)?
By minimizing downtime and the ensuring reliable continuous operation effective thermal protection can improve the overall equipment effectiveness (OEE) by up to 5% and thus increase the economy of the facility.
Ein effective thermal protection is of great importance for continuous operation to prevent motor damage, which extends the mean time between failures (MTBF) by over 20% und significantly reduces unplanned downtimes by about 15%..
The choice of the right protection mechanism – whether PTC thermistors, PTO bimetal switches, or PT100 sensors – must be precisely matched to the motor characteristics and the specific application to achieve the best possible performance and longevity. proper installation, compliance with standards like DIN EN 60947
Die sachgemäße Installation, die Einhaltung von Normen wie DIN EN 60947 and the use of modern electronic relays can fully exploit the reliability of thermally protected motors. and the overall equipment effectiveness (OEE) can be improved by up to 5%.Learn how to optimally protect your motors from overheating in continuous operation and thus avoid costly failures. We show you the best strategies and technologies!
Continuous operation places special demands on your motors. Effective thermal protection is essential in this regard. Discover in this article how to extend the lifespan of your drives while simultaneously increasing operational safety. Do you need individual advice? Contact us at ATEK Drive Solutions.
Do you need a customized solution for the thermal protection of your motors in continuous operation?
Request individual consultation now!
Proactively avoiding motor failures in continuous operation and increasing efficiency.
Overheated motors cause costly downtimes. Effective thermal protection prevents damage and can increase overall equipment effectiveness (OEE) by up to 5%. Preventive monitoring is therefore essential and significantly reduces unplanned downtimes (by about 15%). The goal is always a low-maintenance motor, especially when it comes to a thermally protected motor for continuous operation. Potential beyond mere damage prevention
An optimally designed motor protection acts proactively and goes beyond mere damage prevention.
Correctly dimensioned, it optimizes the life cycle costs and can increase the mean time between failures (MTBF) by more than 20%. Korrekt dimensioniert, optimiert er die Lebenszykluskosten und kann die mittlere Betriebsdauer zwischen Ausfällen (MTBF) um mehr als 20% erhöhen. This is particularly relevant for a motor for continuous operation with integrated thermal protection, as used in pumps, for example. High-efficiency motors also contribute to reducing energy costs.
Basic mechanisms of thermal protection
Basic mechanisms of thermal protection ensure reliable continuous operation. Direct temperature monitoring, for example using sensors integrated in the winding, is crucial, as critical temperatures occur here first. ATEK relies on multi-point measurements for precise detection, which is important for the longevity of thermally protected motors for continuous operation. Special requirements apply to high-temperature motors..Understanding and optimally utilizing thermal protection mechanisms.
Thermistors (PTC/NTC): Precise monitoring
Thermistors, also known as PTC resistors or NTCs, drastically change their resistance when overheated. Typically, three series-connected PTCs monitor critical “hot spots” in the motor winding; an exceedance of the rated temperature by about +10°C triggers the response. They form the core of effective motor full protection, which ATEK employs, for example, in servomotors for demanding continuous operation.
- PTCs (NTCs) precisely monitor winding hot spots through resistance change.
- Thermostats (PTOs) directly interrupt the circuit in case of overheating and provide robust protection.
- PT100 sensors provide continuous temperature data for effective predictive maintenance.
- Automatic reset mechanisms, often found with PTCs, minimize downtime during operation.
- Manual resets, typical for PTOs, require a root cause analysis before restarting.
- The choice of the appropriate protection mechanism depends on the application and safety requirements of each thermally protected motor for continuous operation..
Thermostats and bimetal switches (PTO): Direct circuit interruption
Thermostats and bimetal switches, often referred to as PTO (Protection Thermique à Ouverture), directly interrupt the circuit upon reaching a critical temperature. They offer robust protection and often require a manual reset, ensuring root cause analysis before the motor is restarted. This approach can reduce unplanned downtimes by up to 30% and is a proven method for protecting motors with overheating protection for continuous operation, for example, in compressors.
PT100 sensors: Continuous data for predictive maintenance
PT100 sensors are resistance thermometers that provide continuous temperature data, thus enabling proactive, predictive maintenance. This data allows for precise trend detection and optimization of maintenance intervals, extending the lifespan of thermally secured drives for continuous use. ATEK uses this sensor technology, for example, for bearing monitoring in ATEK nutzt diese Sensortechnologie beispielsweise zur Lagerüberwachung in air-cooled gear motors..
Reset mechanisms: Automatic versus Manual
The choice of reset mechanism – automatic or manual – is highly application-dependent. Automatic resets, typical for PTC-based systems, minimize downtime. Manual resets, often found in PTO switches, serve to minimize risk by enforcing a check before restarting. In conveyor belts, where an unexpected restart can be dangerous, a manual reset is often preferred. thermally protected motor for continuous operation. Choose the appropriate thermal protection for continuous operation precisely.Adjustment to motor characteristics and application
The motor protection must be precisely adjusted to the motor characteristics, the specific application, and the insulation class (e.g., class F, up to 155°C).
A mismatch can lead to unnecessary shutdowns or, worse, to inadequate protection, which can shorten the motor’s lifespan by up to 50%. Ambient temperature is also an important factor in designing the protection for a Auch die Umgebungstemperatur ist ein wichtiger Faktor bei der Auslegung des Schutzes für einen thermally protected motor for continuous operation..
Motor protection switch (MSS) and motor protection relay (MSR): Functional differences
Motor protection switches (MSS) and motor protection relays (MSR) offer different functionalities. MSS often combine overload and short circuit protection and directly switch the main circuit. MSRs, on the other hand, control external contactors and thus offer more flexibility, for example, for soft start functions. MSRs enable finer adjustment of protection, which can be beneficial for a continuous operation motor with thermal protection. Special requirements apply to IEC explosion-protected motors..
Electronic overload relays: Advanced functions
Modern electronic overload relays offer enhanced functions compared to conventional bimetallic solutions. Adjustable trigger classes (e.g., Class 10 to Class 30) allow for adaptation to the motor’s starting behavior and can reduce false trips at high starting currents or frequent switching cycles by up to 70%. This is particularly advantageous in applications such as packaging machines, which often rely on a reliable thermally protected motor for continuous operation. operation.Correctly install thermal protection and ensure reliability.
Correct assembly and connection are fundamental.
An incorrect installation position or inclination of a thermal relay can change its trip behavior by ±5% or more. Correct assembly according to the manufacturer’s specifications, including observing tightening torques, is therefore essential for the reliable function of the thermal protection. An improperly installed protection for a thermally protected motor for continuous operation. can fail in critical situations.
- Correct assembly according to the manufacturer’s specifications is fundamental for the protective function of every motor with thermal protection for continuous operation..
- A pre-installed short-circuit protection through fuses or circuit breakers is essential.
- The installation of thermal protection components should always be carried out by qualified professionals.
- The “Test” button on protective relays often only simulates the mechanical function, not the thermal trip process.
- Regular inspections with appropriate measuring devices by professionals ensure permanently reliable protection.
- The orientation of the relay must be exact, as deviations can influence the trip behavior.
Necessity of pre-installed short-circuit protection.
A thermal overload relay alone does not protect the motor from short circuits. A pre-installed short-circuit protection, achieved through appropriate circuit breakers or fuses (e.g., gG-characteristic, 16A for a 5.5kW motor), is therefore essential for the safety of every thermally protected motor for continuous operation.. Bei flameproof motor. A particularly careful planning of the overall protection concept is required.
Importance of professional installation.
The installation of motor protection components should always be carried out by qualified professionals. Installation errors can significantly compromise the safety and availability of the drive system and, in the worst case, lead to the failure of the thermally protected motor for continuous operation. system. The investment in professional installation pays off through increased reliability and longevity.
Functionality and limits of the test function.
The “Test” button on many protective relays often only simulates the mechanical function of the trip mechanism, but not the actual thermal trip process. For permanently reliable protection of the motor for continuous operation with integrated thermal protection, regular inspections by professionals with suitable measuring devices are essential. Compliance with standards and quality assurance systems for maximum safety.
Normenkonformität und QS-Systeme für maximale Sicherheit gewährleisten.
Standards DIN 44081 and DIN EN 60947 for safety and quality.
Compliance with relevant standards such as DIN 44081 for PTC sensors and DIN EN 60947 for motor protection switches is crucial. Adhering to these standards not only ensures the quality and reliability of the protective components, but is often also a prerequisite for insurance coverage and the CE marking of a thermally protected motor for continuous operation.. In particular, DIN EN 60947-4-1 requires specific tests for motor protection devices.
Manufacturer quality assurance systems according to DIN EN ISO 80079-34.
Quality assurance systems of manufacturers, for example according to DIN EN ISO 80079-34 for devices in explosive atmospheres, ensure consistent production quality. This is an important quality characteristic, especially for thermally protected motors for continuous operation., which are used in explosive areas. Importance of standardized documentation.
Standardized documentation, including the trip characteristic of the motor protection, is essential.
According to standards such as DIN EN 60079-14, the operator must be provided access to relevant information for testing and adjusting the protection for their Gemäß Normen wie DIN EN 60079-14 muss dem Betreiber der Zugang zu relevanten Informationen für Prüfung und Einstellung des Schutzes für seinen thermally protected motor for continuous operation. system. Missing or incomplete documentation can significantly hinder audits and maintenance work.Thermal protection in practice: Learn and apply from case studies.
Case study wood processing circular saw: Dealing with high starting currents.
A classic case study is the wood processing circular saw, which is characterized by high starting currents. The motor protection must be designed so that it does not trip incorrectly. Ideally, a motor protection switch with a delayed trip characteristic (e.g., Class 20) or an electronic relay with adjustable starting bridging should be used to ensure the thermally protected motor for continuous operation. starts safely. This tolerates the high starting current but reliably switches off in the event of an actual overload.
Case study automatic feed systems: Frequent start-stop cycles.
Automatic feed systems are often characterized by frequent start-stop cycles. Conventional bimetal relays can trip prematurely here due to thermal inertia. An electronic overload relay with a higher trip class can increase the number of permissible starts per hour by up to 50%, thus improving the availability of the system that relies on a robust motor with overheating protection for continuous operation. Also, IP55 motors in such applications benefit from this. Case study fan operation: Specific aspects.
Fans that are often operated continuously present specific requirements for thermal protection. Starting currents and especially variable ambient temperatures must be considered in the design.
Choosing the correct trip current and possibly using temperature-compensated protective relays is necessary to ensure reliable operation of the Eine korrekte Wahl des Auslösestroms und gegebenenfalls der Einsatz von temperaturkompensierten Schutzrelais sind notwendig, um einen zuverlässigen Betrieb des thermally protected motor for continuous operation. system. This can be particularly challenging for IP67 servomotors in harsh environments.
Case study pump control: Protection against dry running and overload.
In pump control systems, not only is protection against overload and overheating important, but often also protection against dry running. Modern electronic relays often offer integrated underload detection, based on measuring the cosine phi or active power. This function detects a dry run of the thermally protected motor for continuous operation. and switches off the pump before damage occurs.
