Regarding motor over-temperature protection
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Hello everyone! I have a question regarding methods for motor over-temperature protection: As far as I know, there are three methods, 1) installing a thermal relay ； 2) Add frequency converter ； 3) Add PTC thermistor ； The supplier’s motor has already been developed; it lacks over-temperature protection. Among the three methods mentioned, which one is relatively easy to implement based on the current setup, has a reasonably affordable price, and offers stable performance? Please give me some advice; I don’t know much about electricity.
Today, integrated protectors are used, which enable functions such as quick shutdown, overcurrent and overload protection, zero-sequence protection, grounding protection, as well as control and communication for motors. For example, with Beidou Galaxy’s BDM:), using a frequency converter merely for motor overheat protection is a bit excessive! PTC is generally embedded in the windings during motor manufacturing to provide connection leads, and it is difficult to add them later on.
1) Add a thermal relay； 3) Adding a PTC thermistor is possible; the price is relatively reasonable. The PTC thermistor needs to be installed in an appropriate location, and this requires discussion with the manufacturer
I’ve learned something; thanks for the answers from the second and third floors!
I have another question: compared to these three, what is their accuracy like?
Can it be understood this way? If there is a suitable location, go with a PTC thermistor first, because its accuracy is better than that of a thermal relay, right?
Their protection principles are different. A thermal relay is a protective device used for overload protection of motors or other electrical equipment as well as electrical circuits. Thermistors are used to detect the temperature of the motor stator or rotor, as well as the bearings.
My goal is to cut off the circuit when the motor temperature gets too high, thereby providing protection. Can a thermal relay be used to achieve this? Thank you!
Yes, what is the power of the motor? Generally, for low-power motors, thermal relays or soft starters can be used for protection
PTC + Ma Bao: The PTC is used to detect the stator temperature through embedded coils, while sensors are used to measure the shaft temperature before and after insertion; these functions cannot be replaced by frequency converters or thermal relays. Thermal relays are used for overload protection.