10Hp, 3-phase, 415v, 50Hz induction motor.
The above motor is to run on Star-Delta connection, so how
do i make following hardware selection
1) MCB, 2) Contactor, 3) Wire Gage (Depending on P-P current
or Line Current), 4) OLR,
Please tell in detail how to do the above, so as to get the
ans. of it even if the Hp rating changes.
10 hp=7.5 kW. The manufacturer has to indicate the starting
Let's say the motor is designed for star/delta starting
then according to IEC 60034-12 Tab2 for 6.3 kw up to 25 kw
S1=12 then maximum permissible starting current will be
The short-circuit protection has to be set at
The circuit breaker rating has to be 150 A. The motor
overload has to be set at 1.25*Irated and also will trip
the breaker if the current of 2*Irated will last more than
the permissible stall time [let’s say 4 sec].
The supply cable allowable current [see IEC 60364-5-52]
shall be 1.25*Irated.
Usually a 7.5 kW motor at 415 V rated current will be 13-16
A then the cable permissible minimum should be 20 A.
According to the above mentioned standard 2.5 mm^2 copper
conductor PVC insulated will be ok.
You have to check the voltage drop also: no more than 3%
rated and 10% at start. If DV=1.73*I*[R*cos(fi)+X*sin
(fi)].R,X =total resistance-at 70 dgr.C- and reactance
cos(fi)=0.85 [approx.] rated and 0.3 at start. Sin(fi)=
In this case if the cable length will be 80 m 4 mm^2 copper
conductor has to be employed.
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Where is 2 phase supply used commercially?
can anyone help me regarding bout Electrical designs and calculations .. which text book should i follow as i am a trainee engineer.Description of my work which is Electrical designs like cable sizing, lighting, lightning, Gensets sizing, motor sizing, transformer sizing, generator sizing, circuit breakers, PDB MCC PCC SLDB MLDB panels, Single line diagrams mainly, substation desings, cable routing and layouts, reactive power compensations, power factor improvement, voltage drop calculations, power generations, power transmission, power distributions all calculations.Please help me
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