Tuesday, November 30, 2021

HOW TO TEST TRANSFORMER with Digital Multimeter and Analog Multimeter

 HOW  TO   TEST   TRANSFORMER     with    Multimeter

TRANSFORMER  TESTING    Transformer   consists  of   2 winding  ;   primary winding and secondary winding.   Transformer is  the important device on power supply circuit. It convert  high voltage to low voltage  and provide safety feature as  isolation between input and output ,  Isolation  between  high  AC voltage and  low AC voltage can  achieve   by transformer.  This article explain basic transformer testing.



Step to test transformer with Digital Multimeter.
1. Turn equipment  off ( unplug )  or    remove power source  from transformer under test.
2. Turn rotary switch  to  resistor  test  function.
3. Connect test leads  to  primary  winding.
Good transformer get  measured  resistance value.
Bad transformer  ( open winding )  meter display  " OL "
Bad transformer  ( short turns )  meter display   0 ohm  or  very much low  resistance.
4. Connect test leads  to  secondary  winding.
Good transformer get  measured  resistance value.
Bad transformer  ( open winding )  the  meter display " OL "
Bad transformer  ( short turns )  meter display very much low resistance.


Test   TRANSFORMER
Test   primary   winding , display  resistance value.
Bad transformer display " OL" (for open ).

Bad transformer display very much low resistance  (for short ).



HOW  TO  TEST  TRANSFORMER  with Digital Multimeter
Test   secondary    winding ,display resistance value.
Bad transformer display " OL" (for open ).
Bad transformer display very much low resistance  (for short ).



5. Test transformer core with primary winding.  ( Isolation testing)
Connect test leads   to transformer core  and  primary  winding.
Good  transformer  meter display " OL "
Bad transformer   meter  display some resistance (leak)
6. Test transformer core with secondary  winding. ( Isolation testing)
Connect test lead to transformer core  and  secondary  winding.
Good  transformer  meter display " OL "
Bad transformer  meter display some resistance (leak).

TRANSFORMER
 Test transformer core with primary winding ( isolation testing).
Good transformer meter display "OL"
Bad transformer (leak) meter display some resistance value.



Test   TRANSFORMER
Test transformer core with  secondary  winding ( isolation testing).
Good transformer meter display "OL"
Bad transformer (leak) meter display some resistance value.



7.  Test isolation between  primary winding and secondary winding.
Connect test leads   to primary winding   and secondary winding.
Good  transformer  meter display  " OL ".
Bad   transformer (leak)   meter display some resistance.


TEST  TRANSFORMER
Test isolation between  primary winding and secondary winding.
Good transformer meter display "OL"
Bad transformer (leak) meter display some resistance value.



Step to test transformer with  Analog  Multimeter.
1. Turn equipment  off ( unplug )  or remove power source  from transformer under test.
2. Turn rotary switch to  resistor test function , Rx1 range.
3. Connect test leads  to  primary  winding.
Good transformer get  measured  resistance value.
Bad transformer  ( open winding )   the  pointer point at  " ∞  ".
Bad  transformer  ( short turns )  the pointer point at   0 ohm.
4. Connect test leads  to  secondary  winding.
Good transformer get  measured  resistance value.
Bad transformer  ( open winding )  the  pointer point at  " ∞  ".
Bad transformer  ( short turns )  the pointer point at   0 ohm.


Test   transformer
Test   primary  winding, use Rx1 range ,
 meter display some resistor for good transformer.



Test  TRANSFORMER
Test   secondary   winding, use Rx1 range ,
 meter display some resistor for good transformer.


5. Test transformer core with primary winding. ( Isolation testing).
Turn rotary switch  to   Rx10K range test function.
Connect test lead to transformer core  and primary winding.
Good  transformer  the pointer  point  at   " ∞  ".
Bad transformer  (leak)  the pointer show some resistance value.
6. Test transformer core with secondary  winding. ( Isolation testing).
Connect test lead to transformer core and  secondary  winding.
Good  transformer  the pointer point at   " ∞  ".
Bad transformer (leak) ,  the pointer  point  at  some  resistance value on scale.


TRANSFORMER
Test transformer core with primary winding ( Isolation testing ).
Good transformer  ,  the pointer must point at " ∞  ".



TEST   TRANSFORMER
Test transformer core with secondary  winding ( Isolation testing ).
Good transformer , the pointer must point at  " ∞  ".


7.  Test isolation between  primary winding and secondary winding.
Connect test leads  to primary winding  and  secondary  winding.
Good  transformer  ,  the pointer point at   " ∞  ".
Bad transformer   ,   the pointer  point  at  some  resistance value on scale.



How  to  check  electronic   device