Regular Motor Maintenance To Avoid Failure

Motor Maintenance

A well carefully designed motor maintenance program, when correctly used, can be summed up as

1.Preventive maintenance

2.Predictive maintenance

3.Reactive maintenance

Inspection cycle depend upon the type of motor and the conditions under which it operates.

Motors need maintenance regularly in order to avoid failure and prolong their lifespan. Generally speaking, motors and motor parts should be maintained and tested at every 6 months.

1.Preventive maintenance

The objective of this kind of maintenance is to prevent operating problems and make sure that the motor continuously provides a reliable operation usually, preventive maintenance is a scheduled part of maintenance a whole system.

   

2.Predictive maintenance

The objective of this kind of motor maintenance is to ensure that the right kind of maintenance is carried out at the right time. In order to define these two parameters, it is necessary to monitor the motor operation regularly and thereby detect problems before they actually occur.

3.Reactive maintenance

The main objective of this kind of maintenance is to repair and replace the motor when a failure occurs. Reactive maintenance or breakdown maintenance as it is referred to as well, does not imply any regular service or tests.

The Basics Of Molded Case Circuit Breakers You MUST Know

Molded Case Circuit Breakers (MCCB)

Molded case circuit breakers are interrupting devices with self contained, current responsive elements. These breakers are assembled as an integral unit in a supported and enclosed housing of insulating material.

Depending on the amount of protection required, these breakers can sense internally and then clear under voltage, over current, and short circuit conditions.

Some tripping elements are also externally accessible through control wiring, and other circuit protection can be added. Breakers may rely solely on outside information to perform their prime function. Several trip units may be available for a particular frame size. A specific assembled breaker may have a lower continuous current rating than the current designation of the frame manufacturers.


Contacts often begin to part during the first cycle of a fault. The current breaker must be capable of interrupting the maximum allowable first cycle asymmetrical current. The operating mechanism provides a means of opening and closing the toggle mechanism of quick-make/ quick- break type contacts.(Snap open or closed independent of the speed of handle movement).

Molded case circuit breakers use in restricted to low voltage and medium voltage system 

MCCB Trip Elements

Trip elements trip the operating mechanism of a circuit breaker during either a prolonged overload or short circuit currnent. Some molded case circuit breakers have a screwdriver slot located on the front of the trip unit used for adjusting sensitivity.

The maximum setting is established by protection of the minimum conductor size in the circuit.

Instantaneous Magnetic Trip

Magnetic trip work by using an electromagnet in series with the load current. When the current. When  the current reaches the set point, the electromagnet instantaneously trips.This type of trip commonly found in low voltage breakers.

Thermal Trip

Considered the industry standard, these trip elements work using a bimetal heated by the load current.When overheated, indicating an overload, the bimetal will detect, which causes the operating mechanism to trip.

Thermal Magnetic Trip
A thermal magnetic trip, in addition to provide short circuit protection, guards against long- term current overload existing longer then roughly 10 seconds. Because bimetal deection is dependent on current and time, the thermal unit provides long-time delay for light overloads and fast response for heavy overloads.

Questions to help in preparation about Interview !!!

At the  eve of interview of any company we always have a fear of being rejected or what they ask me in interview.
Here are some of questions related to electrical automation engineering for job interview.

Q-1.  Tell me about your self.
Ans-  I am ____ from _____ .
          I have __ year of experience of it field.
          My highest qualification is _______from ______university.
          In my family i have _____brothers or sisters_____.
          My hobby is _______.
          That all  about me sir.

Q-2    What experience do you have in automation field ? 
Ans-   Hopefully if you're applying for this position you have bags of related experience, and if that's the case you should mention it all. But if you're switching careers or trying something a little              different, your experience may initially not look like it's matching up. That's when you need a              little honest creativity to match the experiences required with the once you have. People skills            are people skills after all, you just need to show how costumer service skills can apply to                      internal management positions, so on.  

Q-3  What is your greatest weakness ?
Ans - This is challenging question -- as if you have no weaknesses you are obviously lying! Be           realistic and mention a small work related flaw. Many people will suggest answering this using         positive trait disguised as a flaw such as " I am a perfectionist. "  I would advocate a certain                degree of honesty and list a true weakness. Emphasize what you've done to overcome it and                 improve. This question is all about how you perceive and evaluate yourself.

Q-4 What challenges are you looking for in this position ?
Ans- The best way to answer question about the challenges you are seeking is to discuss how you       would like to be able to effective utilize your skills and experience if you were hired for this job.

Q-5 What do you know about us ?
Ans- Follow these easy research tips before your next job interview:
        1. Visit company website, look in the "about us".  
        2. Visit the company's linkedin page to view information.
        3. Also read present news about company in " Press release section".

Where Do Electrical Faults Occur The Most?

Causes of electrical faults

A fault is not a natural occurrence. it is an unplanned event which occurs unexpectedly. Electrical faults in an electrical installation or piece of equipment may be caused by

Negligence - that is lack of proper care and attention

Misuse - that is not using the equipment properly or correctly

Abuse - that is deliberate ill treatment of the equipment

By picture presentation we describe

7 Possible points where electrical faults occur 

Point 1- Fault occur in wiring system

All cable connections must be made mechanically and electrically secure . They must also remain accessible for future inspection , testing and maintenance



The only three exception to this rule are when

1. Underground cables are connected in a compound filled or encapsulated joint.

2. Floor warming or ceiling warming heating system are connected to a cold tail.

3. A joint is made by brazing , soldering or compression tool.

Since they are accessible , cable inter connections are an obvious point of investigation when searching out the cause of a fault.

Point 2- Electrical faults also occur at cable termination

Flexible cords are delicate - has the terminal screw been over tightened , thus breaking the connection as the conductors flex or vibrate ?