SU729682A1 - Synchronous contact ac switching device - Google Patents

Description

electromagnet through the contact spring 5 is mechanically connected with the movable power contacts 6. The main drive 7 with the help of the rod 8 acts on the movable power contacts 6 of the apparatus, which are locked to the fixed power contacts 9,

The winding 10 of the synchronizing electromagnet is electrically connected through an additional resistance 11 to the secondary winding 12 of the phase-shifting current transformer, the primary winding 13 of which is turned on. in the circuit of the power contacts of 6.9 apparatus. The magnetic circuit 14 phase-shifting current transformer is made with air gaps in order to increase the leading angle of the shift of the secondary current in the circuit of the transformer relative to the primary current.

Thus, the power contacts 6.9 of the apparatus are directly connected to the synchronizing electromagnet and are autonomous from the main drive 7 of the apparatus.

Structurally, the synchronizing device, in which the contact springs are connected with stationary power contacts mounted on a support allowing for angular displacements, is made as follows (see FIG. 2). The moving force contacts 6 of the apparatus are rigidly connected by means of the rod 3 to the synchronization bar 2 electromagnet. The stationary power contacts 9 are pivotally supported and connected to the contact springs 5. Thus, the contact springs 5 do not affect the movement of the moving contacts 6, the movement of which is carried out by the force of the return spring 4,

When power is applied to the winding of the main drive 7 of the apparatus under the action of the rod. 8, the mobile b and stationary 9 contacts of the device are pre-closed (see Fig. 1). At the same time, the contact 5I return 4 springs are compressed (gin. The current passes through the power contacts and the primary winding 13 of the phase-shifting current transformer, creating a holding force Hcuv in the winding 10 of the synchronizing electromagnet.

In the process of shutting down the apparatus after removing the mechanical pressing with the rod 8 from the power contacts b. they remain closed15 until the electromagnetic forces holding the bark 2 in the tightened state match the opposing forces created by the contact 5 and return 4 springs.

As in the circuit of the winding 10. synchronizing electromagnet and, therefore, the magnetic flux in the working

the gap is shifted relative to the zero of the primary (commuting) current by the lead angle, the moment of unwinding of the power contacts 6.9, determined by the equality of the active and. The force acting will be strictly in front of the current zero. At the same time, the lead angle remains constant over a wide range of switching currents, and its adjustment is performed by selecting the phase shifting parameters of the circuit (additional resistance il and the secondary winding 12 of the phase-shifting current transformer) and design parameters of the magnetic circuit 14 of the phase-shifting current transformer.

Since the measles 2 synchronizing electromagnet is directly connected with the moving force contact and 6,

there is no need to coordinate the moments of the -detection of synchronous and power contacts with the moment of mechanical removal of the rod 8. The difficulty of such coordination lies in choosing the magnitude of the failure of the synchronous and power contacts, and the failure of the power contacts must be less than the failure of the synchronous contacts. In addition, during the operation of the device, the magnitude of the failure of the synchronous and power contacts changes, which leads to a mismatch and a failure in the synchronous shutdown. Therefore, the exclusion of synchronous contacts not only eliminates the canceled shortcomings, but also significantly increases the reliability of the synchronous apparatus as a whole.

In order to increase the stability of the proposed synchronous device, the contact springs of the apparatus b are directly connected with the stationary power contacts 9 fixed to a support that allows for angular displacements (see Fig. 2). When synchronous disconnection of power contacts 6 and 9 at the moment of equality of electromagnetic forces acting on measles 2 electromagnets and counter forces of contact 5 and return 4 springs in the initial stage of their movement, the speed of movement of moving force contacts 6 is much higher than the speed of movement of contact point on a fixed force contact 9. This is due to the greater mass of the fixed contact 9 compared with the moving system of the synchronizing electromagnet. In regen structures, the mass of the sliding junction 9 is 3-5 times higher than the mass of the moving system of the synchronizing electromagnet.

Thus, the opening of the power contacts b and 9 is carried out strictly at a predetermined period of time before the transition, commuting the GO current through zero, regardless of the magnitude of the contact failure and the force of the contact pressing. This allows not only to facilitate the design of the moving system of the synchronizing electromagnet, but also to increase the stability of the timing characteristics of the synchronizing device.

Claims (3)

1. A synchronous contact switching device of alternating current containing moving and stationary power contacts, contact springs, a current transformer with gaps and a phase-shifting circuit, a synchronizing electromagnet, the closure of which is connected to the phase-shifting circuit of a current transformer. characterized in that, in order to increase the reliability and simplify the device, the measles of the synchronizing electromagnet is directly connected to the idle-moving power contacts. 2, The device according to claim 1, characterized in that the fixed power contacts are fixed: pivotally with the possibility of angular displacement and are associated with contact springs. Sources of information taken into account in the examination 1. Author's certificate five No. 319005, cl. H 01 H 9/30, 1971. 2. The author's certificate  47916J, cl. H 01 H 33/44, 1975. 3. Authors certificate No. 522526, cl. H 01 II 33/44, 1976.