What is duty cycle and protection class?

Answer Posted / er. vasim

Duty Cycle:- It is the classification based on time
duration for which a motor will be loaded
According to IsS 4722, following classes are assigned
S1-Continous
S2-Short time duty
S3- Intermitent periodic duty
S4- Intermitent periodic duty with starting
S5- Intermitent periodic duty with starting and electric
breaking
S6- Continous duty intermitent periodic loading
S7- Continous duty with starting and electric breaking
S8- continous duty with periodic speed change

IP Protection:
It stands for Ingress protection, According to IS 4691 IP
is classified as:

In IP their are two numerals, ie:IP56
1st numeral: protection against ingress of solid particles
or human body parts,etc
2nd numeral: protection against penetration of liquid

for 1st numeral
IP 1: protection against solid of 50 mm dia or more
2: protection agianst solid of 12.5 mm dia or more
3: 2.5 mm dia or more
4: 1-2.5mm dia
5 and 6: protection against dust particle

for 2nd numeral
1: protection against vertical fall of liquid
2:protection against fall of liquid at an angle of 15 degree
3: 60 degree
4: 180 degree (ie: heavy rain fall)
5 and 6:protection provided against liquid jet (very heavy
rush of liquid)
7 & 8:protection provided against total immersion in liquied

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