Nate Electrical Exam with 100% Correct Answers 2024, Exams of Electrical Engineering

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Nate Electrical Exam with 100% Correct

Answers 2024

What electro-mechanical control would you use on a cap tube or automatic expansion valve system to maintain the space temperature? - Correct Answer-C: A thermostatic control Open motors are designed to operate at a given temperature rise as indicated on the motor nameplate. What does this mean? - Correct Answer-A: indicates the temp. rise over the surrounding air of a motor when the motor is operating at full-load conditions A voltmeter is connected into a circuit in which of the following ways? - Correct Answer- B: Parallel A low pressure control is usually located on the: - Correct Answer-A: Condensing unit A high pressure control is usually located on the: - Correct Answer-A: Condensing unit The term "nominal voltage" refers to: - Correct Answer-D: The listed voltage Which of the following is a safety control? - Correct Answer-B: High pressure control Low voltage controls are usually designed to operate at no more than: - Correct Answer- A: 25 volts A unit of power equal to one horsepower and delivered at the shaft of a motor is known as: - Correct Answer-B: Brake horsepower What is the purpose of the holding circuit in a magnetic motor starter? - Correct Answer- B: Holds the main contacts closed until the control circuit through the interlock is broken. On a magnetic motor starter, the alloy piece that causes the motor starter to open and shut off the motor if too much motor current is drawn is called the: - Correct Answer-D: Trip armature A set of contacts in a pressure control that close when the pressure increases are - Correct Answer-A: Direct acting Direct acting means "closes on rise". Contacts close on an increase Which of the following control settings is typically non-adjustable? - Correct Answer-B: Range

Ohm's law states: - Correct Answer-A: E = IR

All else being equal, which of the following wire sizes will carry the most current? A: 10 ga B: 14 ga C: 12 ga D: 18 ga - Correct Answer-A: 10 ga The run capacitor on a motor is used to: - Correct Answer-A: Increase torque Doubling the voltage to a resistance will cause the power or watts to: - Correct Answer- C: Quadruple What is impedance? - Correct Answer-A: Opposition to alternating current flow How are fuses sized? - Correct Answer-A: By amperage C: By voltage Capacitors are rated in: - Correct Answer-B: Microfarads C: Volts One horsepower is equal to watts. - Correct Answer-B: 746 How much resistance must be placed in a 220-volt circuit to limit the current to 2 amps?

• Correct Answer-B: 110 ohms Impedance in a circuit is the result of: A: Pure resistance B: Inductive reactance C: Capacitive reactance D: All of the above - Correct Answer-D: All of the above Doubling the voltage to a fixed resistance will: - Correct Answer-B: Cause the current to double When the temperature of a negative temperature coefficient material increases, its resistance will: - Correct Answer-C: Decrease What is the Btuh output of an electric heater rated at 15 Kw? - Correct Answer-B: 51,150 Btuh What is the total capacitance of two 20-microfarad capacitors wired in series with each other? - Correct Answer-B: 10 mf What is the total capacitance of two 20-microfarad capacitors wired in parallel with each other? - Correct Answer-D: 40 mf If a conductor is wrapped around the jaws of a clamp-on ammeter four times and the meter indicated 16 amps, the actual amperage would be: - Correct Answer-C: 4 amps On a standard electro-mechanical thermostat, if the fan switch is in the "on"

position, the indoor fan will: - Correct Answer-C: Run continuously

The coil of a lockout relay is wired in with the contactor coil and in with the contacts of the control it is protecting. - Correct Answer-C: series, Which of the following capacitors is the best choice to replace a 35 mf, 370 volt run capacitor? A: 35 mf, 330 volt B: 35 mf, 390 voltC: 30 mf, 440 volt D: 40 mf, 370 volt - Correct Answer-B: 35 mf, 390 volt A motor is a load. - Correct Answer-B: Inductive The compressor oil safety control is an electro-mechanical control that operates on which two pressures? - Correct Answer-A: Oil pump pressure and suction pressure What is the millivolt reading of a good thermocouple? - Correct Answer-B: 15 mv A high pressure safety control is: - Correct Answer-B: Reverse acting Two silicon-controlled rectifiers wired in reverse parallel with each other allows: - Correct Answer-A: Current flow in both directions Back to back scrs allow alternating current to pass but can be controlled by the switching of the gates to allow for high speed switching Hot surface igniters operate on which of the following voltages? - Correct Answer-B: 120 volts Which of the following mathematical relationships is true of a motor's horsepower if the CFM of a blower were changed? - Correct Answer-D: Hp changes by the cube of the change in CFM If you have trouble with this question you need to study the fan laws and work out a few fan law problems When four diodes are constructed in a bridge circuit and alternating current is brought into the input of the bridge, the output of the bridge provides: - Correct Answer-B: Full wave rectification When photons of light strike the surface of a typical cadmium sulfide photoconductive cell,. - Correct Answer-B: resistance decreases A low voltage control system that primarily operates on two levels of voltage is called: - Correct Answer-B: A digital system A voltage imbalance is a problem associated with which type of

motor? - Correct Answer-B: Three phase motors

An air conditioning compressor has the following motor protection devices: low pressure control, high-pressure control, internal thermostatic overloads and an oil failure control. If the internal thermostatic overloads open, which of the following will take place? - Correct Answer-C: 360 ohms When the internal compressor thermostats or overloads open they shut down the compressor but the control circuit remains in the circuit. There is no oil pressure with the compressor off so the oil failure control trips and locks out the control circuit. By the time the technician arrives the internal thermostats in the compressor have cooled and reset. The technician just finds the compressor out on the oil failure control and can be led to believe that an oil problem exists when the actual problem is compressor overheating Using the standard resistor color code to determine the value of a resistor, what is the resistance of a resistor with the following three colors in this order: red, green, black? - Correct Answer-A: 25 ohms What is the purpose of the resistor wired across the terminals of a start capacitor? - Correct Answer-B: To prevent arcing and possible damage to the start relay contacts Which of the following will cause an increase in the horsepower required per ton of cooling on an air conditioning system? - Correct Answer-C: Both a and b Using an automatic pump down system, the compressor is directly controlled by: - Correct Answer-B: Low pressure control Which of the following test results indicate a capacitor is good? - Correct Answer-A: An ohmmeter is set to the highest ohm scale and its test leads placed across the capacitor terminals. The analog meter's needle moves quickly to the right side of the scale and slowly returns to the left end of the scale.