Industrial Automation and Control Interview Questions

What is cascade amplifier?

 A multiple-stage amplifier in
which the output of each stage is connected to the input
of the next stage.
What do you mean by cascade control? 
Control in which the output variable
of a controller is the reference variable of another
controller(s).

What is command in Control Systems?

Command is an operative order which initiates a movement or a function. The order may be: 

1. direct input to the machine in coded form; 

2. results from a logical interaction of instructions from an outside source with conditions sensed
by the machine; 

3. outputs derived from the computing or comparing function.

What is derating factor?
The factor by which the ratings of component parts are reduced to provide additional safety
margins in critical applications or when the parts are subjected to extreme environmental conditions for which their normal ratings do not apply.

What do mean by interconnection system?

The electrical and mechanical interconnection of any one or all of the six levels
of interconnections generally common to electronic equipment. The six levels of interconnections are: intramodule, module to motherboard, intramotherboard, motherboard to back panel, backpanel wiring and input/output.
What is manual control in industrial automation?
 Control in which a direct or indirect human manipulation of the final controlling element
is carried out. In the process industry, this is generally done via a standardized signal. Can also be defined as direction of a computer by means of manually operated switches. 

What is automatic control system?

 A control system which operates without human intervention. It is subdivided into a controlling system and controlled system.

What do you mean by automatic zero-and full-scale calibration?

Zero and sensitivity stabilization by servos for comparison of demodulated zero-and full-scale signals with zero and full-scale references.

What are pneumatic system?

A system which makes use of air for operating control valves and actuators (cylinders,
motors).

What Are Common Electrical Interview Questions?

Electrical interview questions one might expect to answer during a job interview may fall into three categories: education, experience, and certification. In addition, preparing for a job interview will generally entail having a current, well-prepared resume and demonstrating desirability as a potential employee. Electrical interview questions will depend upon the specific job within the field; an applicant for a job as a residential electrician will field different questions from an electrical engineer.

Presenting a well-prepared resume is one of the primary tips for a job interview. This document will form the basis for many of the interview questions addressed to the applicant. The resume should provide specifics about all pertinent past and current employment information as well as contact information, education, and work experience. Dates and duration of job experience and electrical training are typically a necessity.

If a job is being sought from a large employer, an applicant may have at least two interviews, one from a human resources (HR) representative and one from a qualified manager. Questions regarding general qualifications and references might be expected in an interview by the HR staff member. Electrical interview questions typically will be asked by a manager with electrical training and will often include questions about knowledge and skills directly related to the job at hand.

Questions To Ask Electrical Contractors

Hiring electrical contractors is an important task. One of the most important parts of the process of choosing an electrical contractor is a brief question-and answer session. The questions should be designed to answer any questions you may have about the contractor. The time spent talking with the contractor should also give you a better idea if that's the kind of business person you want working in your home.

• What are your qualifications? This is a basic question that should be among the first you pose to any person who is going to perform work for you. What you want to hear is that the contractor is licensed and has experience in a wide variety of areas, including the specific work that has you searching for electrical contractors.
• Tell me about this job. Does the contractor seem knowledgeable about the job? Is he or she able to explain the project is easy-to-understand terms? This is a good opportunity for the contractor to impress you with his knowledge, demeanor, personality and salesmanship. You don't have to find the nicest person in the world to do some electrical work in your home, but it doesn't hurt if you sense that the two of you will get along well. After all, there is always the possibility of a problem with the job, and at that point you want someone who is reasonable and easy to communicate with.
• Do you carry the appropriate insurance? This should be more than a yes or no answer. You want to know if the electrical contractors you are interview have general liability and worker's compensation insurance. Legitimate electrical contractors will expect the question and have the paperwork to proof they carry proper insurance.
• Is your company in good standing with the state? If any of the electrical contractors you are considering haven't properly handled licensing or tax obligations with the state, you're better off moving on to other candidates. This isn't the kind of question you take at face value. You should inquire with your state's Secretary of State or Attorney General offices - one is likely the agency the maintains records on corporations working in the state.
• Please provide several references. In fact, it's a good idea to ask for references from the last few jobs. That may or may not be possible, since every customer won't agree to be listed as a reference. However, for electrical contractors who do good work, most customers are happy in return to offer positive references.
• Give me a cost and timeline for the job. You want more than when the job will be finished. What is the expected work schedule and will there be any time off during the project? As far as the price, what could cause the final price to come in higher or lower?
• Can you put the job terms in writing? Also ask for a contract, which serves as a means of protection for both you and the electrical contractors. The contract should briefly describe the job, include the cost, time frame and whether the contractor is expected to clean up each day or at the end of the project.

Electrical Contactor, Switch, Circuit Breaker Difference

An Electrical Contactor is a switch. In simple words contactor is a switch which closes its contacts with the help of relay. Most of the contactors operate by electromagnet, thus causing the contactors to close and open by spring or gravity. The main difference between the contactors and switch is that contactors can be operate remotely whereas switch has to be manually operated at the location. Contactors can be controlled by manual or remote push buttons or by automatic devices such as timers, float switches, thermostats, pressure switches and so on. As the control is both remote and automatic they are employed in lighting, heating, air conditioning and motor loads

• Circuit Breaker interrupts the fault current which electrical contactor cannot. Generally contactors are connected in series with fuse. Therefore during short circuits fuse acts as fault current interrupting element in the circuit. In simple contactor is a switch with remote control and automatic functions. Circuit breaker is employed to protect the circuit and electrical contactor is used to open and close the contacts
• Contactors are generally employed in low voltage and medium voltage level. Circuit breakers can be employed up to EHV systems for switching purpose

Fuse Advantages Disadvantages in a Electrical Circuit

Fuse is the cheapest protection device in electrical circuit against short circuits and overloading of circuits. Fuse is a metal wire or thin metal strip which has the property of low melting point which is inserted into the electrical circuit as protective device. Fuse provides protection against excessive currents which can flow in circuit during short circuits. Under normal working condition the current flowing through the circuit is within safe limits but when fault occurs such as short circuit occurs or when load more than circuit capacity is connected to it, current exceeds the limiting value results in fuse wire gets heated up, melts and break the current. Thus fuse protects the machine or electrical equipment against the excessive currents.

Time for blowing out of fuse depends on the magnitude of the excessive current. Larger the current more rapidly the fuse blown off. Thus fuse have inverse time characteristics. Such characteristics is desirable for protective gear. 

Fuses are used on low and high voltage circuits of moderate to high capacity where frequent operation is not not expected. Fuse is employed for protection of distribution transformers, small and medium size motors, lighting circuits, branch circuits of distribution lines, in industrial plants and commercial buildings. 

Advantages:

• Fuse is cheapest type of protection in an electrical circuit
• Fuse needs zero maintenance
• Operation of fuse is simple and no complexity is involved
• Fuse has the ability to interrupt enormous short circuit current without producing noise, flame, gas or smoke
• The operation time of fuse can be made much smaller than operation of circuit breaker. It is the primary protection device against short circuits
• It affords current limiting effect under short-circuit conditions
• Fuse inverse time current characteristic has the ability to use for over-load protection

Disadvantage:

• During short circuit or overload once fuse blows off replacing of fuse takes time. During this period the circuit lost power
• When fuses are connected in series it is difficult to discriminate the fuse unless the fuse has significant size difference

Electrical Controls Design Engineer

Electrical controls design engineers require a high level of analytical ability to solve the unusual problems that can arise during their jobs. As the job usually involves working in coordination with other engineers, good team spirit and interpersonal relations is needed. 

Other critical criteria include knowledge of product design and automotives, familiarity with basic machine types, high proficiency in reading and interpreting engineering drawings using the knowledge of advanced engineering methods, tools and procedures, testing, manufacturing and assembling.

Electrical control design engineers also help manufacturing electrical equipment like machinery controls, electric motors, lighting and wiring in automobiles and buildings, aircraft radar and navigation systems, power generating, transmission and controlling used by electric utilities. 

Electrical control design engineers can specialize in different fields such as mechanical, electrical, electronic biomedical, automotive and civil engineering. The projects undertaken are quite interesting and can range from redesigning to maintenance of automotives.

Compared to the other heavy equipment jobs, an engineer specializing in electrical control and design has a less strenuous job. Electrical controls design engineer jobs account for nearly 35% of the total engineering opportunities available. There are job options in nearly every heavy equipment and construction company and the flexibility of the job allows one to relocate quite easily.

Electrical controls engineer interview questions

Electrical systems/electrical controls engineers help develop, design, implement, and maintain electrical systems in many different industries. They may specialize in one particular discipline, such as electrical power distribution, telecommunications, or electronics component design.

Electrical systems/electrical controls engineers have opportunities to benefit the environment in different ways, depending on the projects they work on. They may work on energy-efficient home appliances or HVAC systems. They might work on wind farm projects, or update energy transmission systems so that they can move power from wind farms to areas of need, or help to implement a smarter grid system. In architecture and construction, they can design efficient wiring or lighting systems for new buildings that are seeking Leadership in Energy and Environmental Design (LEED) certification. In fact, some electrical engineers seek LEED Accredited Professional (AP) status themselves, which demonstrates their expertise in sustainable building design practices.

Whether they're developing circuit boards or designing power substations, these professionals have similar work processes. First, they communicate with management or clients to determine the purpose, limitations, and goals of a project. Next, they do preliminary design of the product, often using computer aided design (CAD) software. They perform calculations and make technical drawings of the product or system. Once design is complete and finalized, they might oversee the production or construction of the product, including monitoring the production or installation of components, troubleshooting problems, and ensuring that safety and construction requirements are met. Some electrical engineers also maintain previously-installed electrical systems. A single person may participate in one or all of these steps in the product's life.

The title "Electrical systems/electrical controls engineers" are common job titles for electrical engineers doing green-related work. Electrical engineers can be green across a variety of industries, but the most prevalent green fields are in electrical systems and electrical controls. Most jobs for green electrical engineers in Minnesota are posted by employers as "electrical engineers."