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Water Level Sensor
What sensor is used to measure the level of water in a tank?
thakur.rajesh.ranjan
- Sep 25th, 2010
A small rubber ball, we generally use in our dewatering sump for water level sensor. This gives command mechanically to level switch.
ravs42
- Aug 6th, 2010
A simple mechanical model for water level indicator includes a float(rubber ball) providing a mechanical link to the indicator i.e. d output. When the water level rises the float due to it's light weight raises up and via the link the pointer will move to display the required output.
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Transformer Humming
What causes transformer humming?
Krishna Kant Gupta
- Mar 13th, 2012
Humming sound in the transformer is due to the stray losses in the transformer due to the leakage flux.this flux produce eddy currents in the nearby conductive areas.The humming sound is the result of...
bittu123
- Nov 9th, 2011
Humming sound caused by magnetostriction phenomenon. Magnetostriction is change in physical dimension of material because of change in magnetic field.
Since, there is varying magnetic field in transformer causes vibration of core in gap available due to bad insulation. and starts soud hum -
Electrical Machine Harmonics
What is harmonics and how they are produce in electrical machine?
ravs42
- Aug 6th, 2010
Harmonics are the integral multiples of the fundamental values of current/voltage quantities. Generally it is caused due to non linearity caused by the load which adversely affects the supply side. Main impacts occurs in capacitors, telecommunication lines, power transformers, etc.
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Spark Plug
When the power supply cable got sparked, it gets burnt or caches fire then explain why the spark plug in our automobiles never get burnt or catch fire even it spark's?
ravs42
- Aug 6th, 2010
Generally in automobiles we have an alternator that produces ample AC supply that is converted to 12V DC supply via the help of rectifiers and regulated IC usage. The 12V is then feed to the batterri...
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DC Motor Amature Control
Why armature control is used, not the field control for DC motors?What is the drawbacks in field control method?
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Transformers and Varying DC Current
Will DC current that varies, for example a DC square wave, but that only sinks to neutral (0V) and not enough to cause current to flow in the opposite direction, pass through a transformer? If so, how will you be able to calculate reactance for this?
ravs42
- Aug 8th, 2010
A DC square wave will have a very high value of dv/dt as compared to the pure sine wave. When it is striked to transformer, a high value of dv/dt would not be responded by it, as a result, the waves ...
Abhijit_atrangi
- Feb 22nd, 2010
No, only change in flux will induce the emf in a ckt. and that only feasible with AC that goes in opposite direction also. But in case of DC that produce flux with no change that never cause any emf in circuit. In case of DC square wave you change the magnitude of a wave from zero to max.
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Run DC machine as a Generator
It is possible to run one DC machine as a generator or motor purposely? What adjustment we have to do for that operation?
ravs42
- Aug 21st, 2010
DC generators has got some limitations. The machine speed and output cannot be increased above certain limit due to commutation problems and cost. Besides using an alternator along with a rectifier circuit can be the best option to generate DC supply.
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Transformer Taping
Why tapings of Transformer is always provided on HT side? why not on LT side?
ravs42
- Aug 21st, 2010
It is because of two reasons1.high voltage regulation.Large range of voltage can be obtained.2.less current value on the HV side,as a result,no sparking problem.
Raman Jain
- Dec 3rd, 2009
Tapings in transformers are provided at HV side . The reasons are : 1. Less current has to be handled .2. As the LV windind is wounded first i.e near the core and HT winding is wounded on the top of the LV winding. So it is easier to provide Taps on HV side.
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DC Voltage Control
How we can step-up or step-down the DC voltage directly?
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Current Transformer
Explain why the secondary terminal of current transformer should not be lift open circuited.
ravs42
- Aug 21st, 2010
Due to high ratio,if the secondary is left open a very large voltage will be developed at the secondary.As a result the core vl be saturated n operator working nearby vl face severe accidents.
deepanshu_jadon
- Mar 10th, 2010
In CT secondary side is not open because it has large voltage difference
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what is meaning by the SKIN effect in electrical circuits
veerateja
- Jun 2nd, 2011
In ac electrical circuits due to varying magnetic fields they induce eddy inside the center of conductor .Due to the induced eddy currents they restrict the current flow on the center and pushes the c...
ravs42
- Aug 8th, 2010
When alternating current flows thru the conductor, magnetic field intensity in the inner side is more, as a result flux concentrated on the inner conductor is very high. Since inductance of the coil i...
