Interested to Buy Any Domain ? << Click Here >> for more details...
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.
- 1 Answers
- 6290 Views
- Engro, I also Faced
- E-Mail Answers
Answer Posted / 7anoter4
10 hp=7.5 kW. The manufacturer has to indicate the starting
current.
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
Istart=12*7.5*1000/1.73/415=125.2 A.
The short-circuit protection has to be set at
1.25*125.2=156.5 A.
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
[ohm].
cos(fi)=0.85 [approx.] rated and 0.3 at start. Sin(fi)=
(1-cos(fi)^2)^0.5.
In this case if the cable length will be 80 m 4 mm^2 copper
conductor has to be employed.
| Is This Answer Correct ? | 6 Yes | 0 No |
Post New Answer View All Answers
how can we change the polarity of Alternating current rapidly? how frequency of ac can be controlled and changed easily?
my diploma certificate in my higher education college
what are the reasons of CT circuit faulty in busbar protection scheme?
in parallel operation of power transformer why the distance between power transformer and capacitor bank feeder is necessary to know
Why 15Amp. MCB is suitable to carry load of 1.5Ton Ac please Explain?
Why in ESP Positive earthed
Sir pl provide 5 year sample paper for post junior engineer(electrical).I have currently applied for junior engineer (electrical) on RRB Ajmer
EXPLAIN THE TRANSFORMER MAINTENANCE?
please send me last 5 year interview questions
I am inpecting a 10kVA UPS what tests should i do and should i observe?
pls,send the previous year written test questions.
Explain advantages of storage batteries
if we apply 1000ADC instead of 100ADC or We apply 50ADC instead of 100ADC,What will be happened in the test result value.Pl explain
What is touch potential and step potential?
What is the power requirement of tamil nadu for one month?
