Ingles goya 7 - 1

Single-phase motors: The change of their direction of rotation can be accomplished just by exchanging phase and neutral connections. Feature higher efficiency than three-phase motors. Are larger than three-phase motors (the rated power value being the same). All answers are true.

In general, control circuit conductors: Have a 1.5 mm2 cross-section and are identified by red insulation. Have a 1.5 mm2 cross-section and are identified by black insulation for the phase conductor and blue insulation for the neutral conductor. Have a 1.5 mm2 cross-section and are identified by red insulation for the positive conductor and black insulation for the negative conductor. None.

According to the number of phases, electric motors can be: Single-phase. Two-phase. Three-phase. a) and c) are correct. All are correct.

Indicate the right statement about the contactor coil: It is formed by a high-diameter cupper wire winding featuring a low number of turns. It is the part of the contactor that can be distance-controlled. A coil's three terminals are identified as A1, A2 y A3. None.

A motor frame is connected to: It is connected through the metal screws, so no conductor is needed. The earthing electrode through the neutral conductor. The earthing electrode through the protective conductor. None.

Please mark the incorrect answer: A contact has two types of contacts: power and control contacts. Control contacts are also called auxiliary contacts. Power contacts feature higher breaking capacity. Auxiliary contacts have higher breaking capacity values that power contacts. All are incorrect.

Find out the correct statement: Electric motors are static machines that transform electric energy into mechanical energy. Electric motors are rotating machines which convert electric energy into mechanical energy. Electric motors are rotating machines which convert mechanical energy into electric energy. None.

A contactor comprises the following parts: Coil, electromagnet and electric contacts. Coil, pneumatic circuit and electric contacts. Coil, electromagnet and thermal elements.

Which of the following statements about the contactor is true? : It is robust and reliable, because it doesn't include any delicate mechanisms. It is a pneumatic device which can be distance-controlled for making or breaking currents. It is used for protecting motors upon failure of one phase. a) and c) are correct.

Mark the right statement about three-phase motors: Delta connection is recommended for the lowest rated voltage of an electric motor. Star connection is recommended for a motor's highest rated voltage. There is a device called contactor that is used for protecting motors from a phase failure. The direction of rotation of three-phase motors can be changed by exchanging any two phases' connections.