Tuesday, November 30, 2021

HOW TO TEST SWITCH Toggle switch Rocker switch Limit Switch


Test    SWITCH    Toggle  switch   Rocker  switch   Limit  Switch
HOW TO  TEST    SWITCH 


All   kind  of switch   has mechanical  contacts.  The most basic of contacts   is   NC  type contact ( Normally Close )  and   NO   type contact ( Normally  open ).  Some switch has only 1 NC contact  , some switch  has  only  1  NO contact  , and some model consist  of  many  contacts ;  NO  NC Common terminals.      The circuit diagram of  switch  has   printed  on  its  body.    How  to  check  switch   it depends on contact  type of  witch.


NC type contact ( Normally Close )  , Terminal 1 and 2 is connected

NO type contact ( Normally  open )  Terminal 1 and 2 is  not  connected
Basic  output contact form  consists   of   NC  and  NO contact





Step to check  switch


1. Turn   rotary  switch to  continuity test function  of   digital multimeter.
2  Connect  test  leads  to  the  NC contact  of  switch.   The  meter  will  beep  if  it is a  good NC contact.   Bad  NC contact  , the meter does  not beep.   After that change  switch  position by pressing to  ON and  OFF.   The good contacts  will change status  from ON  to OFF or  OFF to ON.
3.  Connect  the  test leads to  the  NO  contact.   The  meter  will  not  beep  if  it is  a good NO contact.   Bad  NO  contact  , the meter will  beep ( short circuit).
After that change switch position by pressing to  ON and  OFF.   The good contact will change status from OFF  to ON  and ON  to OFF.   These changing of contact  represent results  on  multimeter display.
4. Test   every  NO   and NC contact set.  If there is only  1 contact is bad , the  switch  is  not  good.
then find the replacement.

Test    SWITCH
Test   NC contact  of  switch     , the  meter  will  beep  if  it is  a good NC contact. 
Bad  NC contact  , the meter will  not beep.



Test   SWITCH
Then change  the toggle position , the  NC  contact connection  will change too,  from beep to OL.



Test   SWITCH
Test   NC contact  of  switch     , the  meter  will  beep  if  it is  a   good NC contact.  



Test   SWITCH
Test   NC contact  of  switch     , After changing  switch position the internal contacts of switch will change too , from connected  to disconnect.   
Represent  as  beep for connected and OL display  for disconnected.