Zaporozhye enterprise «element converters» produces a series of modules MTOTO optotiristornyh for currents from 40 A to 250 A. They are a monolithic structure, inside which are placed two thyristors connected in half-bridge circuit, as well as two optical elements. A feature of these modules is that their power components and controls are galvanically isolated from the module housing. In addition, controls are galvanically isolated from the power elements of the module. The heat from the elements is removed through the ceramic insulator and metal base.
Shown in the figure a schematic diagram of the power supply for the entire range of modules optotiristornyh Zaporozhye enterprise «element converters».
Consider the principle of operation of the circuit. An alternating voltage of 12 V is supplied to the transformer TV1 wave rectifier V1-V4, a smoothing capacitor C1 and supplied to the control circuit. Detector «zero» on the transistors T1, T2 at the start of each half cycle of the mains voltage rapidly discharges the capacitor C2, and then he slowly charged by the current flowing through the resistor R5. As a result, «sawtooth» voltage is supplied from capacitor C2 to the noninverting input of op amp DA1, enabled by comparator circuit. He compares the voltage at the inverting input given by the regulator RR1.1 with «sawtooth» voltage at the non-inverting input. In each half-cycle of the network as soon as the voltage at the non-inverting input of op-amp DA1 becomes greater than the inverting comparator switches, and its output will be a positive voltage. Phase front rectangular output pulses of the comparator depends on the voltage level defined by the regulator RR1, and recession — is tied to the time of zero voltage sinusoid network.,
RR1. Light bulb goes off smoothly. Disconnect the AC voltage of 220 V / 50 Hz. Disconnect the meter. The power supply is ready for operation.
Due to the fact that the control modules is carried out with direct current, the modules are kept open during the entire time of the applied control current. This allows you to switch the load with low input current without distorting its shape.
When adjusting the value of the DC voltage to the circuit can be connected to both active and inductive (motor) load. The same applies to the control circuit
After pressing SB1, the relay K1 which is placed on its contacts automatic blocking and simultaneously connects the lower figure for the output resistor R12 to ground the unit. At the same time it begins to shine light diode LED, indicating the operating status of the device.
Power transformer TV1, supply chain management, not more than 10 VA.
To adjust the circuit you must connect an incandescent lamp 100 watts and the operating voltage of 220 V to the output terminals of modules VT1, VT2. The broken wire power emitting diode modules VT1, VT2 set milliamp and fully enter the resistor R11. The resistance of the voltage regulator RP1 fully enter. The input circuit applies an alternating voltage of 220 V / 50 Hz. Briefly press SB1. This turn of LED. Gradually reduce the resistance regulator RP1.
Resistor R11 is the current set-emitting diode is 140 mA. In this light at the output terminals of the power supply should light the full fervor.
Then gradually reduce the resistance regulator AC voltage. Also in this case, the inductive load can use a transformer.
The above-described control is used to supply power transformers to 50 kVA in a device for welding roll cold rolling at one of Kramatorsk.