how to test your led driver at 500 voltage

How can I provide high voltage to test equipment when supply voltage is 230 voltage ?

A variable voltage autotransformer (also known as variac) is a transformer which is able to transform or produce AC mains voltages at different desired levels at its output. Thus unlike an ordinary transformer its output voltage is not fixed, rather can be varied manually to obtain more than a single voltage. The voltage obtained from such a device is normally an AC at mains level, which may be higher or lower than the applied input voltage depending upon its settings.

Method 1:when we use single phase

Variac provide normally up to 270 voltages. but some time we will doing the test of led bulb etc load at 450-500  voltage because  of some time electricity  will coming phase to phase ,for solution to  this problem  we will using  step up transformer with variac .



                                                                  IMAGES: SINGLE WINDING VARIAC

                                                                                                                                                 IMAGE: Low voltage convert in high voltage through transformer using variac.


Method 2: when we use double winding variac

The normal output range of variac  is 0 to 270 volt in single phase.

When testing of load at 2 phase supply we use  special variac.This variac made up of two winding.



                                                                          Image :  Two winding variac



                                        IMAGE: low voltage convert in high voltage when we use two winding variac. 



Method 3: when we use 3 phase supply using variac

When testing of load at 2 phase supply we use  special variac.This variac made up of three winding.

The normal output range of variac is  0 to 470 volt in three phases. Three such variable auto transformer when connected electrically in star & mechanically in tandem, became suitable for operations of 415 v 3 phase a.c. supply & to give output of 0 – 415 v or up to 470 volts.



                                                                        Image: 3 phase supply variac



                                               Image: low voltage convert in high voltage using  3 phase supply variac




Our knowledge there are some companies which are providing variac in the India. for your help we are giving below  the name of some companies. For your kind of information  we are not responsible for any problem.    

 We are providing reference of some of the companies we or our customers have recommended.
 You can have direct delaing with them. We are only providing information.   

 Variac Suppliers Companies

          1       RAVISTAT

Address :
Plot No.A-420, Road No.28, 
Opp. Emco Co., Ram Nagar, 
M.I.D.C., Wagle Estate, Thane (W) – 400604 
Maharashtra, India 
Phone : 
91-22- 2582 4626 / 17 
Fax : 
91-22-2582 4647 
Email : 


           2       Green dot electric limited

              Address :

              G-9 Hemkunt Tower /
              Modi Tower,

              98,Nehru Place

              New Delhi 110 019

              Email :

              Phone     : +91 11 2622 2088 
              FAX          : +91 11 2622 2088


            3  contact no.- +919910558428



(Updated: Jan 21, 2021)