0
They are marked on the transformer. H1 and H2 primary, X1 and X2 secondary. Dual voltage primary H1, H3 H2, H4, Dual voltage secondary X1, X3, X2, X4.
Additional Answer for Unmarked TransformerFor a completely unmarked transformer, a continuity test will confirm which terminals belong to which windings, and a resistance test will identify the high-voltage (higher resistance) and low-voltage (lower resistance) windings. In North America, HV winding terminals are identified by the letter 'H' and LV windings by the letter 'X'.For a two-winding, four terminal, transformer, to test for polarity, the transformer should be orientated so that the HV windings are on the far side of the transformer, and the LV windings are on the nearest side. By convention, the left-hand HV terminal is then marked H1, and the right-hand terminal is marked H2. The LV terminal adjacent to H2 is then connected to terminal H2, so that both the HV and LV windings are in series. A voltmeter is then connected between the LV terminal adjacent to H1, and the H1 terminal itself. A low-voltage supply is then connected across the HV windings (i.e. between H1 and H2). If the voltmeter registers a voltage higher than that applied to the HV windings, then the transformer is of additive polarity, and the LV terminal adjacent to H2 should be marked X1 and the LV terminal adjacent to H1 should be marked X2. If, on the other hand, the voltmeter reading is less than the applied voltage, then the transformer is of subtractive polarity, and the LV terminal adjacent to H2 should be marked X2, and the terminal adjacent to H1 should be marked X1.
By convention, when terminal H1 'goes positive' during the AC sine-wave, then terminal X1 should also 'go positive'.
A similar process applies to multi-winding multi-terminal Transformers. Again, the windings of such transformers must have their terminals identified first -a simple continuity test will reveal these. The rule is that an odd number (e.g. H1, etc.) represents the 'start' of a winding, and an even number (e.g. H2) represents the 'end' of a winding. Again, a simple resistance test will identify the high-voltage (higher resistance) and low-voltage (lower resistance) windings.
For UK transformer, HV windings are identified as A-B, etc., and LV windings as a-b, etc.
Still curious? Ask our experts.
Chat with our AI personalities
Judy
Rene
DevinAdd your answer:
Earn +20 pts
What do transformer coil have to do with the way the transformer control voltage in alternating current?
Transformer coils are normally used to step down power from high power lines to a power you can actually use in your house. This works through the ratio of windings on a coil to the windings on the output side.
How is a DC permanent-magnet motor reversed?
Reverse the polarity of armature windings of the motor.
How do you calculate rating of 11 kv transformer?
The KVA rating of a transformer is based on how much heat the transformer can dissipate. The BIL rating is based on how well the windings are insulated. There are other "ratings" as well. Rough calculations can be done, but tests are generally performed to prove the calculations (transformer designers will design on the conservative side to insure the transformer meets specification). These type of calculations are best done by a computer. You will struggle to determine the hot spot max temperature rise in a transformer by hand.
A transformer has 20 primary windings and 100 secondary windings If the secondary voltage is 25 V find the primary voltage?
Voltage on primary/Primary turns = Voltage on secondary/Secondary turns
What are the approximation of open circuit and short circuit test of transformer?
A short-circuit test is done to determine the power lost in the resistance of the primary and secondary windings of the transformer. It is done at full load current but with only enough voltage to give the required current with the secondary short circuited. An open-circuit test is done at full load voltage but no current is taken from the secondary, and this enables the power lost in the magnetic core of the transformer to be measured. As well a power, the tests also allow the inductances to be measured as well as the resistances, in order ot characterise the transformer fully.
