Transformer

Machine tool transformer refers to an electrical energy conversion device used in machine tools or mechanical equipment. It is mainly used as a control power supply for general voltage of machine tools and mechanical equipment, a control circuit for general circuits in mechanical equipment, and a power supply for local lighting and indicator lights.

Ⅰ. Manufacturing materials of machine tool transformers:

Iron and core materials: mainly silicon steel sheets. The quality and efficiency of the transformer have a great relationship with the quality of the silicon steel sheets used.

Winding material: usually enameled wire, yarn covered wire, silk covered wire. In general, use high-strength heat-resistant enameled wire, which has good electrical conductivity and heat resistance, and has a certain degree of corrosion resistance.

Insulation material: In the winding transformer, the isolation between coil frame layers and the isolation between windings should use insulating materials. The general transformer frame material can be made of phenolic cardboard, polyester film is used between layers, and yellow wax cloth is used for isolation between windings.

Impregnating material: impregnating insulating varnish can enhance the mechanical strength of the transformer, improve the insulation performance, and prolong the service life.

Ⅱ. Functional characteristics of machine tool transformers:

1. With voltage conversion function;

2. With filtering anti-interference function;

3. It has heat resistance, moisture resistance, stability, chemical compatibility, low temperature resistance, radiation resistance and non-toxic environmental protection characteristics.

Ⅲ, the principle analysis of machine tool transformers:

The machine tool transformer is based on the principle of electromagnetic induction. The primary winding and the secondary winding are sheathed on a common iron core, and the mutual coupling between the magnetic circuit and the circuit realizes the transfer of energy from the primary winding to the secondary winding.

When a sinusoidal AC voltage U1 is applied to both ends of the primary coil, there is an alternating current I1 in the wire and an alternating magnetic flux ф1 is generated. It passes through the primary coil and the secondary coil along the core to form a closed magnetic circuit. A mutual induction potential U2 is induced in the secondary coil, and at the same time a self-induction potential E1 is induced on the primary coil by ф1. The direction of E1 is opposite to the applied voltage U1 and the amplitude is similar, thus limiting the size of I1. In order to maintain the existence of the magnetic flux ф1, a certain amount of power consumption is required, and the transformer itself also has a certain loss. Although the secondary is not connected to the load at this time, there is still a certain current in the primary coil. This current is called "no-load current". ".

If the secondary is connected to a load, the secondary coil will generate a current I2, and therefore generate a magnetic flux ф2, the direction of ф2 is opposite to ф1, which will cancel each other, so that the total magnetic flux in the core is reduced, so that the primary The self-inductance voltage E1 decreases, and as a result, I1 increases. It can be seen that the primary current has a close relationship with the secondary load. When the secondary load current increases, I1 increases and ф1 also increases, and the increased part of ф1 just supplements the part of the magnetic flux offset by ф2 to keep the total magnetic flux in the core unchanged. If the loss of the transformer is not considered, it can be considered that the power consumed by the secondary load of an ideal transformer is the electric power obtained by the primary from the power supply. The transformer can change the secondary voltage by changing the number of turns of the secondary coil as needed, but it cannot change the power that the load is allowed to consume.

Ⅳ, the use environment of machine tool transformers:

1. Ambient air temperature -5℃ to +40℃, the average value of 24 hours does not exceed +35℃;

2. The altitude of the installation site does not exceed 2000M;

3. The relative humidity of the atmosphere does not exceed 50% when the ambient air temperature is +40℃, and it can have a higher relative humidity at a lower temperature. The average maximum temperature of the wettest month is 90%, and the monthly average minimum temperature of the month It is +25℃, and takes into account the condensation on the surface of the product due to temperature changes.

Ⅴ. Inspection regulations for machine tool transformers:

Transformer inspection should meet the following requirements:

1. The daily inspection should be at least once a day, and the night inspection should be at least once a week.

2. The number of inspections should be increased in the following situations:

a. Put into operation for the first time or within 72 hours after overhaul or transformation.

b. When the weather changes suddenly (such as thunderstorm, strong wind, heavy fog, heavy snow, hail, cold wave, etc.).

c. During the hot season and peak load period.

d. When the transformer is overloaded.

3. The daily inspection of transformers should include the following:

a. The oil temperature should be normal, there should be no oil leakage or oil leakage, and the oil level of the oil conservator should correspond to the temperature.

b. The oil level of the casing should be normal, and there should be no damage, cracks, serious oil pollution, discharge marks, and other abnormal phenomena on the outside of the casing.

c. The transformer tone response is normal.

d. The hand feel temperature of each part of the radiator should be similar, and the cooling accessories should work normally.

e. The moisture absorber should be intact and the adsorbent should be dry.

f. Lead joints, cables, and bus bars should show no signs of heating.

g. The pressure release device, safety airway and explosion-proof membrane should be intact.

h. The tap position and power indication of the tap switch should be normal.

i. There should be no gas in the gas relay.

j. All control boxes and secondary terminal boxes should be closed tightly and free from moisture.

k. The appearance of the dry-type transformer should be free of dirt.

l. The transformer room should not leak water, the doors, windows, and lighting should be intact, well ventilated, and the temperature should be normal.

m. The transformer housing and various parts should be kept clean.