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3dDesignBand said: Furse strike risk software V5 in accordance with BS EN 62305-2 Risk Management.
Hello all!
I’ve got a question to engineers design of Lightning Protection Systems. What software do you use into your work, especially to identify the most suitable location(s) for the air terminal(s)?
Best regards
observe the oil temp. and oil pressure of the transformer at night and day .. usually during night time oil temp. go down… i wonder this transformer is outdoor type.
Yes, definitely you will save kVA loading on the Generator. At the same time it is important to know for me that your generation. In fact I work for Power Quality solutions for PF improvement. it is better to know that whether the importing kW & Power used locally.
I hope this helps?
Bye!
Hasan J
adoy said:
why does a core creates a power factor and how does it happend?
The core of the tx is made up of material having some hysteresis loss and eddy current loss.To supply these losses ,a working component of no load current.no load current has to supply magnetic current also to magnetise the core which is 90 degree out of phase with v(lagging ).This gives rise to no load power factor angle which is @ 70-80 degree.
@electricalexpert65 said:
do you mean a magnetic core?
Power factor results from the inductive nature of a coupling system. To overcome thiis negative effect, capacitors are used to balance the inductivity. Usually sytems rated in VA shall be multiplied by a factor, often between 0.8 and 0.9, to calculate the usable power in Watts.
To understand soft starters you need to understand the basics of strting induction motors.
An induction motor has a torque/speed characteristic which tells you the torque that the motor will produce at every speed from zero to synchronous speed with rated voltage (400V) applied. The load will also have a torque/speed characteristic. You need to understand these if you are going to play with soft starting. To start the motor must produce sufficient torque at standstill “Locked Rotor Torque” to overcome the load torque of the device it is to drive. Once started the torque produced must stay above that of the load in order to continue to accelerate. Eventually the motor settle at a point where the load torque and motor torque are equal which will usually be around rated speed.
At rated voltage (400V) the motor will produce “Locked Rotor Torque” at standstill, the value of which will be dependent on the design of the motor. The torque will be proportional to the square of the ratio of applied voltage to rated voltage so if you reduce the applied voltage to 200V, the locked rotor torque will fall to 25% of the rated value which may or may not be sufficient to overcome the load torque. If it is not sufficient the motor will simply sit there in a stalled state drawing approx 1.5 to 2.0 times its rated current without any cooling and either trip the protection circuit or burn out.
Electronic soft starters generally control the start by ramping the voltage up slowly and monitoring the starting current so this is not likely to happen. They will detect a constant stalled condition and shut down before you do damage. However, if you are playing with a reduced voltage starter such as star/delta starter, primary resistance or reactor, you need to get the motor and load torque/speed curves and calculate the minimum voltage that will produce the torque you need to ensure that the motor gets away from rest and also passes the minimum torque point often known as the “pull up torque” with the reduced voltage.
Don't forget also that the voltage drop along the cable is increased during starting due to the higher than rated current being drawn and thus the voltage at the motor terminals may be even smaller that the ratio of the applied voltage to the rated voltage.
GOODEVNING,
the calculation of a cathodic protection sytem depends at first to the objet to protect (its material, dimensions, geometry, caoting ), at second of the envirnement (soil, sea, river…).
the envirnement is catactrise with its resistivity, if the resitivity is too low, and if its caot isn't made of lagging, and if its the electrolyt isn't sufuric acid then you can protect the objet with a system of cathodic protection.
th e calculation depends en the external surface of the objet and ist type of coating.
there's same vlaues isccated in nace standards or europeen standards that give you grid of values to use in calculation of cathodic protection
adoy said:
why does a core creates a power factor and how does it happend?
power factor is not a physical term. Its hypothetical. It says how effectively power is used. What i understand from your question is why some amount of power is utilised to magnetise the core.. Is it what you want to know..? if yes, the answer is; allmost all cores are made of some materials which has certain properties of resistance and inductance/capacitance. to overcome these factors some mmf is required which is pulled from supply power.
May be this might be helpfull? http://www.opamp-electronics.com/tutorials/inrush_current_2_09_12.htm
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You can try “ionisation” type lightning conductors. Usualy you can download the dimensioning software from the manufacturers website/
Here are soem manufacturers, distributors:
Zucchini – Contact nearest Legrand distributor
Canalis – Contact nearest Schneider dealer
Eaton(Moeller) also can provide busbar system
EAE – http://www.eae.com.tr/
I hope it was usefull !
The lightning arrestor will be inthe midlle
Q²=L²+W²
L=Roof long demention
W= Roof waid demention
h= hight of lightning arrestor
Z= buildind hight
if Z<30m ……….h=0.5Q+1
IfZ >30m ………h=(3/5)Q
As long as the frequency range at the location of installation of the panels in which the termianls are installed does not fall under the natural frequency of vibration, in which case there will a tendency for opening up of the connection, it is very good arrangement. Most of the off-shore installation does not prefer this arrangement, as the vibration levels are in very wide range and short distance.
Fluorescent bulbs contain mercury and pose a danger to the environment.Some may be required to pay for disposal of fluorescent bulbs.If the bulb breaks, it contaminates it's surroundings icluding food. Proper clean up can be expensive. LED Light Bulb use less energy than a Compact Fluorescent for the same light output.
