How to test the quality of advertising light transformer with multimeter

This depends on the model of the output transformer you want to measure. Different models have different internal windings. It is best to use the drawing to see which windings are connected to each pin. You can use a multimeter to test whether the windings are connected. There is an open circuit and whether there is a short circuit between each winding. However, since the resistance of the windings is very low, it is difficult for a multimeter to judge if the winding is slightly short-circuited. Generally, it is determined based on experience.

Answer: The connection method of transformer Yd5 is as shown in the figure:

The transformer uses the principle of electromagnetic induction A device to change AC voltage, the main components are primary coil, secondary coil and iron core (magnetic core). The main functions are: voltage conversion, current conversion, impedance conversion, isolation, voltage stabilization (magnetic saturation transformer), etc. According to the purpose, it can be divided into: power transformers and special transformers (electric furnace transformers, rectifier transformers, power frequency test transformers, voltage regulators, mining transformers, audio transformers, medium frequency transformers, high frequency transformers, impact transformers, instrument transformers, electronic transformers , reactor, transformer, etc.). Circuit symbols often use T as the beginning of the number. For example: T01, T201, etc.

Method 1: First use the resistance setting RX1 or RX10 of the multimeter to measure the coils on both sides of the transformer. Both coils must be connected. The primary resistance is large and the secondary resistance is small (voltage reduction). Then measure the primary and secondary resistance. If it doesn't work, the basic measurement is good.
Use both ends of the primary coil of the transformer to connect to the AC voltage 50-100 volt range of the multimeter, and use a dry battery to touch both ends of the secondary coil of the transformer.
At this time, the multimeter's needle should swing strongly, which is the function of induced current and mutual inductance voltage. This proves that everything in the transformer is normal and there is no inter-turn short circuit.
Method 2: Use the resistance level of the multimeter. Measure the DC resistance of the primary coil. If the resistance is small. It means there is no wire in the winding. Neither a digital multimeter nor an analog multimeter can judge whether a 10KV power transformer is good or bad. This kind of multimeter is just an auxiliary tool in power transformer detection and has no practical significance. Don't think that the multimeter has many uses.
The detection of power transformers is a highly technical task. The current power transformer testing tools are basically digital testing instruments. It is generally carried out by a company with high-voltage testing qualifications. Because it is related to the personal safety of the majority of users and the safe use of electricity by electrical equipment connected to the transformer.
Take the simplest insulation resistance test of a 10KV power transformer as an example. A 2500V megohmmeter is used to pre liminarily judge the insulation resistance of the primary winding and shell of the transformer; the secondary winding and The insulation resistance value of the shell; the insulation resistance value between the primary side and secondary side windings.