SU685469A1 - Thyristorized generator for electro-erosion machines - Google Patents

Description

(54) THYRISTOR GENERATOR FOR ELECTRO-EROS

MACHINES

The drawing shows the principal on the generator circuit.

Thyristor generator contains

DC source 1 in SOS

power sources of 2 and under the burning 3 voltage, power circuit of the erosion gap, power thyristor 4, TOKOorpaHHtTOBaiushchee resistance 5 / erosion gap 6, resistance 7 ear, resistance 8, protective ignition current, and power diode 9; main switching cell: thyristor 10, recharging choke 11, switching capacitor 12; additional switching cell: thyristor 13, recharge choke 14, switching capacitor 15 (switching cells are connected between each other by diode 16 and additional diode 17), power thyristor damping circuit: limiting choke 18 and blocking diode 19, choke 20 and idling diode 21; the charging circuit of switching capacitors: diode 22, choke 23 and resistance 24. The generator operates as follows.

When the DC source 1 is turned on, the com, mutating capacitor 12 is charged to the polarity indicated in the drawing without brackets along the circuit: 1-12-17-14-22-23-23 -24 1, and the switching capacitor 15 - to the analog field chain rity: 1-11-16-15-22-23-24-1. Upon receipt of the control and micca on the power thyristor 4 on the idling resistance 7, and, accordingly, on the erosion gap 6, a voltage pulse is generated, ensuring the ignition of the erosion gap b with a current limited by the resistance 8 along the circuit: 2-4-5 -6-8-3-2. In this case, S5UDD 9 is biased by the inverse of the undervoltage voltage 3, after the erosion-gap gap is broken, the main part of the ignition voltage 3 is applied to the resistance 8, and the diode 9 opens, allowing current to flow from the power source Chain 2: 2-4-5-6-9-2. The process of quenching and restoring controllability of the power thyristor 4 begins after switching on the switching thyristors 10 and 13. When the control pulses arrive at the thyristors 10 and 13, a recharge of the capacitor jets 12 and 15, each in its cell-12-10-I- 12 and 15-14-13-15 in the polarity shown in the drawing in brackets,

After the process of recharging and switching capacitors, the thyristors are quenched. Thyristor 10 is quenched by capacitor 2 through

choke 11 by applying reverse voltage, and thyristor 13 is quenched by capacitor 15 through choke 14. Quenching of power thyristor 4 occurs simultaneously with quenching of switching thyristors 10 and 13, but switching capacitors 12 and 15 are connected to it in parallel, first each along its own alignment circuit 12 -17-14 and 15-16-11 and directly to the power thyristor through the choke 18, limiting the quenching current and the blocking diode 19. The process of restoring the control of the thyristors is provided by recharging the house of the switching capacitors from {inverse polarity in parentheses) in a straight (without parentheses).

The recovery time of thyristor control is equal to the recharge time of when the 4H4 capacitors from the reverse polarity to zero along the POWER circuit: 2-12-17-14-18-18-5-6-9-2 for capacitor 12 and 2-11-16- 15-18-19-5-6-2 for a condenser. 15 and along an additional circuit: 2-12-17-14-22-23-24-3-2- for a condenser and 2-11-16-15- 22-23-24-3-2 for the capacitor 15. However, the total electrical resistance of the additional circuit is chosen significantly more than the main electrical impedance of the power circuit, therefore, the recovery time is almost determined by the parameters s power circuit. To reduce the idle losses of the generator, there is a recharge circuit: choke 20, diode 21, reducing the power consumption from the direct current source 1 during the recharge of running capacitors from reverse polarity to direct.

The generator operation mode was described above, when both switching thyristors are turned on, and the switching cells form a synchronous co-switching unit. However, in idle mode, there is no need to turn on two com- puter cells, and the normal operation of the generator is ensured by switching on one switching cell, for example, with a thyristor of 10 o When the generator is operating in the mode of significant currents (working stroke, short circuit) lytipyk) let the thyristor 13 of the second cell enter when there is a current in the erosion gap, and thus the switching capacity of the switching node is increased,

Another mode of operation of the controller is also possible - alternately connecting 2 and commuting cells in order to obtain a predetermined frequency of the generated pulses with a reduced period of operation 2 times