Posted tagged ‘gap’

Latest Interview Questions & Answers

September 16, 2011

01-interview method-interview nervousness-interview notice

1. What is Auto Dosing?

Auto dosing is an automated system of feeding the equipment with liquid products. It is the ideal way to ensure the correct calibrated dose at the right time every time in auto.


2. Difference between Codes, Standards and Specifications?

  • Code is procedure of acceptance and rejection criteria.
  • Standard is accepted values and compare other with it.
  • Specification is describing properties of any type of materials.

3.  Difference between Strainer and Filter


Strainer for coarse size, Filter is more accurate than Strainer.


4. What are differences between Welding & Brazing?

In Welding concentrated heat (high temperature) is applied at the joint of metal and fuse together.

In Brazing involves significantly lower temperatures and does not entail the melting of base metals. Instead, a filler metal is melted and forced to flow into the joint through capillary action.


5. What does a pump develops? Flow or Pressure

A pump does not create pressure, it only creates flow. Pressure is a measurement of the resistance to flow.


6. Which is heavier 1kg of Iron or 1kg of Cotton? and why?

Both of them have same weight. The only difference is the volume of Iron is small compared to Cotton.


7. What will be the position of Piston Ring?

In 180 degree angle the Top ring, Second ring and Oil ring are fixed. Position the ring approximately 1 inch gap below the neck.

INDUCTIVE CHARGING

August 23, 2011

02-powermat-iphone-4-wireless-battery-charger-wireless charging mat-wireless receiver case-new wireless technology

In the future all electronic devices will be wirelessly powered. Small, battery-powered gadgets make powerful computing portable.

The battery charger should be capable of charging the most common battery types found in portable  devices today.  In addition, the charging  should be  controlled from the base station and a bidirectional communication system between  the pickups  and base  station  should be developed.


Inductive Power Systems:

Inductive Power Transfer (IPT)  refers to the concept of transferring electrical power between two isolated circuits across an air gap.  While based on the work and concepts developed by pioneers such as  Faraday and Ampere, it  is  only recently that IPT has been developed into working systems.

Essentially, an IPT system can be divided into two parts;

  • Primary and
  • Secondary.

The primary side of the system is made up of a resonant power supply and a coil. This power supply produces a high frequency sinusoidal current in the coil.  The secondary side (or ‘pickup’) has a smaller coil, and a converter to produce a DC voltage.

01-ecoupled wirelss charging technology-inductive coupling-keep battery life higher-concept-illustration

Working of Inductive Power Transfer:

In this system communications signals are encoded onto the waveform that provides power to the air gap. Communication from the primary side to the secondary is implemented by switching the power signal at the output of the resonant converter between its normal level  and a lower level which is detectable by the pickup but still provides enough power to control the pickup microcontroller. This process is called Amplitude Shift Keying (ASK). This is achieved by varying the output voltage of the buck converter which provides an input DC voltage to the resonant converter.

01-electric vehicles-charging-batteries-wireless charging of electric cars-Delphi_Witricity_Wireless

Communication from the secondary to the primary is achieved by a process called Load Shift Keying (LSK).  This involves varying the loading on the pickup.   Any load on the pickup will reflect a voltage on the primary circuit proportional to the load.  Therefore a variation in the load on the pickup can be detected by the charging station.

The communications system must provide two discrete levels of voltage reflected onto the primary side,  to represent the on and off states for digital communications. The difference must be easily detected on the primary side to provide a robust communications channel. Signals are decoded by simple filters and comparators which feed a  digital signal to the microcontrollers.

Advantages:

EV wireless charging parking 9-29

IPT has a number of advantages over other power transfer methods  – it is unaffected by dirt, dust, water, or chemicals.  In situations such as coal mining IPT prevents sparks and other hazards.  As the coupling is magnetic, there is no risk of electrocution even when used in high power systems.  This makes IPT very suitable for  transport  systems where vehicles follow a fixed track,  such as  in factory materials handling.