Johnson Controls Electrical Technician Interview Questions and Answers

An encoder is a device or circuit that converts information from one format to another.

• An encoder can be a hardware device or a software program.

• In the context of electrical engineering, an encoder is often used to convert analog signals into digital signals.

• Encoders are commonly used in communication systems, robotics, and industrial automation.

• Examples of encoders include rotary encoders used in motor control and opt

PLC stands for Programmable Logic Controller, used in industrial automation to control machinery and processes.

• PLC is a digital computer used for automation of electromechanical processes.

• It uses a programmable memory to store instructions and specific functions.

• PLCs are commonly used in manufacturing plants, assembly lines, and robotic devices.

• They can be programmed using ladder logic, function block diagrams, or stru...read more

Industrial automation involves the use of control systems such as robots and computers to handle different processes and machinery in an industrial setting.

• Industrial automation helps improve efficiency and productivity by reducing human intervention in repetitive tasks.

• It involves the use of sensors, actuators, and controllers to monitor and control various processes.

• Examples of industrial automation include automated...read more

Star delta controlling is a method used to reduce the starting current of induction motors.

• Star delta controlling involves initially connecting the motor windings in a star configuration for starting, then switching to a delta configuration for running.

• It is commonly used for large induction motors to reduce the starting current and torque.

• The transition from star to delta configuration is typically controlled by a mot...read more

In star delta connection, typically two contactors are used.

• In star delta connection, one contactor is used for star connection and another contactor is used for delta connection.

• The star contactor is typically rated for the current of one winding, while the delta contactor is rated for the full motor current.

• Using two contactors helps in reducing the starting current and torque in the motor.

• For example, a 3-phase moto...read more

Single line diagram for DOL is a simple representation of Direct-On-Line motor starter circuit.

• DOL starter consists of a contactor, overload relay, and start/stop push buttons.

• The single line diagram shows the connections between these components.

• The power supply is connected to the contactor, which is then connected to the motor.

• The overload relay is connected in series with the motor to protect it from overloading.

• St...read more

I am an experienced Electrical Engineer with expertise in designing and implementing electrical systems.

• I have a Bachelor's degree in Electrical Engineering from XYZ University.

• I have worked for 5 years at ABC Company, where I designed and implemented electrical systems for commercial buildings.

• I am proficient in using CAD software for creating electrical schematics and layouts.

• I have experience in troubleshooting and ...read more

Ohm's Law is a fundamental principle in electrical engineering that relates the current flowing through a conductor to the voltage across it and the resistance of the conductor.

• Ohm's Law states that the current (I) flowing through a conductor is directly proportional to the voltage (V) across it and inversely proportional to the resistance (R) of the conductor.

• The formula for Ohm's Law is: V = I * R, where V is the vol...read more

The current unit is the ampere (A), which measures the flow of electric charge.

• The ampere is named after the French physicist André-Marie Ampère.

• Current is the rate at which electric charge flows through a conductor.

• Other common units for current include milliamperes (mA) and microamperes (μA).

The voltage unit is measured in volts (V).

• The voltage unit is denoted by the symbol V.

• Voltage is the potential difference between two points in an electrical circuit.

• Common examples of voltage units include millivolts (mV), kilovolts (kV), and megavolts (MV).