Engineering and Technology

 Manual Push Button Starters vs Automatic Starters Manual push-button starters are used for fewer numbers of motors or temporary motor running operations. These starters are made with two or three load contacts. Two load contact starters are used for single phase motor starting or DC motor. Whereas the three load contact starters are used for three-phase motors operation. Manual Push-button type starters are made integral and not fractional power size or horsepower size. The two load contact type starters are generally used to control 5 horsepower single-phase motor or 2 horse-power DC or direct current motor. The three-load contacts starter is capable of controlling three-phase motors powered up to 10 horsepower or 7.5KW. A manual three contacts push-button starter is shown here below. Manual Push button starter Also, you can see the circuit schematic for such a start below as in industry you will deal with the circuit schematic and not the actual starter drawing. Manual Push Butt...

Motor circuit Troubleshooting. Reasons for Motor overloading In the process industry motors are used all over. Thousands of motors in the single process industry are not a big number. Such electric motors are used to drive different types of mechanical loads like pumps, fans, belt conveyors, mixers, grinders, or cutters. Mostly Induction motors are used in industry. They can be single-phase or three-phase. Three-phase motors are very common in the industry due to their efficient operation and robust design. In normal conditions motors are running smoothly without giving any trouble. But sometimes when load running conditions are not even, the motors trip on overload. This motor tripping on overload is necessary to prevent the motor from blowing and burning. If the motor is not tripped in case of an overload, the motor takes more current which heats up the motor, and eventually motor burns due to much current consumption. To prevent the motor from such catastrophic burning an overload p...

  Supersonic anti-ship missiles – not very stealthy! The advantage of a ship with a low radar signature is that it is less visible to anti-ship missiles that typically have active radar homing during the terminal phase. There are other missiles that use infrared homing, so a low infrared signature is important as well. A more advanced missile also can cheat the ship’s electronic signature, for example, the JSM mentioned above which has an RF sensor under development in Australia. As mentioned earlier, ships rely on a close-in weapons system (CIWS) to destroy incoming missiles. The supersonic missiles give the CIWS very little time to react before it hits the ship. There is cur-rent controversy since Russia and China have supersonic anti-ship cruise missiles and the United States and allies only have relatively few in service. There are several reasons for this. Faster missiles tend to fly at higher altitudes where the air is thinner, making them visible from a greater distance as c...

Car immobilizer defect and problem needed to be solved A high-quality cassette deck has been given which is by Grundig which I would like to use, but it needs a set of drive belts. I have not had good luck obtaining suitable belts here or overseas and wondered if any readers could suggest a source. Also, we recently purchased a 1994 car which had an engine immobilizer fitted from new. The documentation for the car means the service manual indicates it was installed by Fortronic Forcefield Car Security Systems. All of their communication contact listings in the paperwork for them are no longer valid. I am sure some readers here know anything about these systems and particularly, how to bypass or disable such immobilizers.  It is operated in the way that a 6.35mm phono plug is inserted into a stereo headphone-type socket on the dashboard and then removed. We would have 60 seconds time or one minute time to insert the ignition key and start the car. I see no brand on the immobilizer m...

 Medical thermometer accuracy  In this current blog post, I am discussing a chronic shortage of thermometers, and many of them may be inaccurate, as I pointed out in my article on thermometer calibration. Many cheap digital thermometers are only accurate to ±2°C, and in some cases can be worse than that. Even high-quality branded thermometers which are from pharmacies and hospitals can be inaccurate. If you get a high temperature reading and worry that you may be sick, only to find out that the thermometer was reading high! We have an infrared thermometer. This cost me $15 some years ago (currently they cost a minimum of $80) and I checked it on the calibrator as being accurate to within ±0.5°C. We had pointed a medical thermometer at our foreheads, and we have been checking ourselves every day, even though we know we are well. My body temperatures readings vary quite a bit, depending on the time of day and whether we have recently eaten. Now I have a baseline for my own healt...