▁the ▁closer ▁when ▁it ▁is ▁needed ▁to ▁open ▁the ▁door . ▁When ▁opening ▁the ▁door ▁manually , ▁the ▁op ener ▁portion ▁is ▁still , ▁so ▁the ▁opening ▁is ▁smooth ▁and ▁quiet . ▁P erman ently ▁engaged ▁– ▁the ▁motor ▁driven ▁mechanism ▁( the ▁op ener ▁portion ) ▁is ▁always ▁joined ▁to ▁the ▁closer ▁( if ▁present ) ▁and ▁to ▁the ▁door . ▁When ▁opening ▁the ▁door ▁manually , ▁the ▁user ▁is ▁also ▁driving ▁the ▁op ener ▁portion , ▁so ▁the ▁opening ▁is ▁rough ▁and ▁no isy . ▁Elect ro - h yd ra ul ic ▁types ▁are ▁inher ently ▁quiet ▁and ▁smooth ▁during ▁manual ▁opening , ▁as ▁the ▁motor ▁and ▁p ump ▁are ▁off . ▁ ▁External ▁links ▁ ▁http :// www . const ruction w it ness . com / Pub lished - Art icles / Autom atic - Do ors - S ens ors / The - In s - Out s - of - Autom atic - Do or - Operation . aspx ▁The ▁Ins ▁and ▁Out s ▁of ▁Autom atic ▁Do or ▁Operation ▁Over view ▁of ▁A NS I ▁safety ▁standards ▁hyd ra ul ic ▁door ▁closer ▁examples ▁on ▁aircraft ▁hang ar ▁doors ▁ ▁Category : E lect rome chan ical ▁engineering ▁Category : Autom ation ▁Category : Do ors <0x0A> </s> ▁Kar im abad ▁( , ▁also ▁Roman ized ▁as ▁Kar ī m ā b ā d ; ▁also ▁known ▁as ▁Kar ī m ā b ā d - e ▁Ar b ā b ī ) ▁is ▁a