Thermal Overload Protection For Hermetic Motors

They may also be used in commercial motors which must function in high pressure corrosive environments.

Thermal overload protection for hermetic motors.

There is one cylindrical stator and a three phase winding is symmetrically distributed in the inner periphery of the stator. Klixon 3hm hermetic overload protector are new generation product designed to meet the demands of tomorrow s compressors. A thermal protector integral with the motor approved for use with the motor it protects on the basis that it will prevent dangerous overheating of the motor due to overload and failure to start a protective device integral with a motor that will protect the motor against damage due to failure to start if the motor is part of an approved. In this instance the protection is designed to prevent damage within a motor or other similar device caused by overheating.

This motor thermal overload protection scheme is very simple. Electrical mechanical and thermal motor characteristics define the frame needed for effective motor protection running stage starting stage and locked rotor conditions serve to determine the main motor parameters motor heating and thermal damage motor characteristics depend on both positive and negative sequence current in the. The amount of current through relay 49 depends on the degree of imbalance of the bridge. Overheating or high current are generally caused by other factors that overload the motor like substituting the wrong motor or lack of proper ventilation around the.

Thermal overload relays are one of the most common and economical motor overload protection devices especially for single phase motors. The degree of protection that an internal protection device provides is classified in the iec 60034 11 standard. Due to such symmetrical distribution when three phase power supply. As mentioned thermal overload relays contain a bimetallic strip and a bimetallic strip is a mechanical device that converts temperature change into mechanical displacement.

When either exceeds the motor s limit the protector will shut the motor off until it cools. The type of thermal overload for which the thermal protection is designed 1 digit. As the temperature of the stator winding increases the electrical resistance of the detector increases which disturbs. The rtd of the stator is used as one arm of the balanced wheatstone bridge.

If larger motors 10 kw are subjected to these higher currents for a longer time damage should be expected. The thermal overload protector on a motor monitors both motor temperature and current. In order to also ensure the thermal overload protection of the motor in the cases of supply asymmetry and loss of a phase high quality motor protection relays have mechanisms with phase failure sensitivity differential release. Another type of overload protection often called thermal overload protection is built into certain mechanical devices such as motors or engines.

Tp is the abbreviation for thermal protection.