Answer / navnit bhimani

Motor full load current=H.P.x1.5 in three phase line
Motor full load current=H.P.x4 in single phase line
you can select 20% over size than full load current.

Answer / prabhu gnanasekaran

All power contactors has to be selected as per the TYPE 2
CO-ORDINATION chart. Which will have the KW rating of the
motor with Line current and starting current. So TYPE 2 CO-
ORDINATION chart will be the base for the selection of
power contactors.

Answer / sahilsmohan

This is depend of utilization of motor :
A.C motor) A.C 1 to A.C 4 : slightly
inductive,slipring,squirel cage ,starting ,stoping, and
plugging, inching .

DC motor ) DC1 TO DC4 slightly induction, series
/shunt,staring stopping, pluging, inching

Answer / amit kansara

first of all determine what is the duty type - ac-2/ac-3 /ac-4
accordingly select the right contactor for manufacturers
catalogue.

Answer / pvr.parthasarathi

For selecting a power contactor for a particular motor the following points are to be considered.
1) Type of the motor ie. Squirrel cage, Slipring .
2) Full load of the motor and its Voltage .
3) Operating cycle of the motor ie. S1 , S2 -----.
4) Nature of the drive ie. cycle of operation such as normal , jogging, Breaking etc.

So selecting the contactor for a motor does not have single point formula. But as a thumb rule for 3 phase motors it can be selected at 130 percent of FLC, if all other factors are normal.

Answer / pramod

As per the different manufacture the give its selection
chart but techanically calculate the motor full load current
of the motor and select the nearst current size of contactor
as per different manufacture Power Contactor List

If one tertiary phase i.e. R,Y or B is earthed of a loaded type tertiary delta connected (Without load)of a power auto transformer, what is its advantage/disadvantage?

0 Answers   Amara Raja,

What should be the conservator minimum oil level required in 2 mva transformer

2 Answers   JSW,

is it possible to flow a current between nutral and earth in a circuit? although nutral and earth having same potential diffrence? i=0/r=0A if any body now any solid reason because i am getting a triping problem in rcbo due to nutral and earth shorting???

2 Answers  

Why 3 phase induction motor getting supply in body if one of it's phase is cut

0 Answers  

what is the function of Moulded case circuit breaker, why it is called Moulded?

0 Answers  

draw a dol with the following rtds,stop/start,ct,vt and o/l supply is 6.6kv and the coil is 110v

1 Answers   Anglo Eastern,

what should be the motor rating for pumping water for house hold use from 60km far lake and what formula is to use please tell me

1 Answers  

why shoud in High tension cable( above11KV etc.,)a semiconducting material coating will be there on insulation?

1 Answers  

WHY IS RESTRICTED EARTH FUALT PROTECTION NEEDED?? WHY CANT DEIFFERENTIAL PROTECTION SUFFICE???

14 Answers  

is it true there's a big difference in using Cummins or Denyo...especially power output or leakage

0 Answers  

what is the different betweem earthing and neutral?

8 Answers  

What is the fuction of UV & how it works in circut breakers? is it one type of relay?

4 Answers