iam interesting to design the control panel for 3 phase
pump motors by controling single phase switches.iam plan to
use fuse,contactor & relay for motor protection .how can i
select the voltage & amps rating for fuse,contactor & relay
plz guide me .if anybody clarify my doubt means it will
more helpful for my future .

Answer Posted / kuldeep singh

Fuse should be 2.0-2.5 times of full load current,
Contactor shall be 2.o times of fullload cureent ( with
AC23 duty) ,relay should be such that full load current of
motors is in mid the range of relay settings,

Isolater rating shall be 2.5 times of full load current

use 4 Amp fuse for your control circuit and aux contactor
of 2no + 2 nc contact etc

for more ask

kuldeepuee@rediffmail.com

KULDEEP SINGH
B.TECH
IITR

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