Polarity marks show the connections where the input and output voltages have the same

instantaneous polarity, this is important when transformers are connected in parallel.

Transformer polarity depends on whether the coils are wound around the core clockwise or

counterclockwise, and how the leads are connected. Often, polarity marks are shown using

symbols, such as a dot or plus-minus marks, on the transformer and nameplate.

We can categorise the polarity of the transformer to two types,

1. Additive Polarity

2. Subtractive Polarity


DC Kick/Flick Test:

For this test, a dc battery, a dc voltmeter or ammeter (preferably

analog), and test leads are required. This method is a quick and easy test for polarity, but

there is a possibility that it may leave remnant flux in the transformer. Remnant flux may

cause saturation when the CT is next energized.


The steps of the dc kick test are as follows:

1. Connect the positive of the voltmeter to the a2 (marked) terminal of the high-voltageside of the transformer and the negative lead to the a1 as shown in Figure.


2. Connect the positive terminal of the battery to the polarity terminal (.) and negativeterminal of the battery to the nonpolarity terminal of the transformer winding under test.


3.Momentarily touch or connect the battery’s positive terminal to the polarity terminal (.)ofthe transformer winding under test.


4. Closely watch the needle or analog scale of the voltmeter. It should jump in the positivedirection. This happens in a fraction of a second, so the meter must be monitored veryclosely. If the voltmeter kicks in the positive direction, the polarity marks are correct. If itkicks in the negative direction, the polarity marks are incorrect.