SU31485A1 - Device for sparkless opening of contacts of contact measuring device - Google Patents

Description

In heating installations with automatic temperature control, a device that controls temperature is often used, it is switched on like a pyrometer and has devices for closing auxiliary circuits (relay contactors) by means of contacts, and the arrow of the device affects the KOTOpbie in one way or another. The design of this device is usually such (a sensitive galvanometer) that it is not possible to use its arrow to directly open the contacts, since it also makes contact, due to sparking, burns. Eliminating sparking by reducing the current in the circuit containing the contacts is undesirable because it is associated with the need to use an intermediate relay, and therefore with the complexity of the circuit. Therefore, usually, devices are used to eliminate sparking, by means of which the circuits, contacts are automatically bypassed or disconnected before opening. The present invention relates to such a device and consists in a special form of its implementation, namely, in the connection circuit of all devices.

The drawing shows a diagram of the device.

(228)

In the heating resistance circuit A of an electric furnace, the temperature of which is controlled by a galvanometer b, an automatic switch K is turned on, equipped with two coils and F; these coils are on the one hand connected to different poles of the current source supplying the furnace A, and on the other hand they are connected to the corresponding contacts EI or Fj of the galvanometer. The closing of the circuit of the coils E or F is carried out using the arrow C of the galvanometer, which is brought into contact, depending on the temperature of the furnace, swivel, on the axis Dr., DI with the yoke D either with the contact EI or with the contact FI.

In the event of a decrease in the temperature of the furnace when the arrows D and the arrow E and the contact EI are closed and the circuit-breaker A / C are closed and the coil E is connected to the power supply circuit, the circuit-breaker will close and close.

At the moment of its closure, it shunts the coil E circuit, as a result of which the subsequent lifting of the drag D and opening of the contacts C and I, an arc does not form between it. At. on switch, / C, in the case; the re-closure of the contacts C and fu, the current in the coil E circuit will not and autoedatic switch will remain on.

If the temperature in the furnace has increased sufficiently, arrow C closes contact FI, which closes coil F. The coil F will operate and turn off the switch K, and this also causes the coil circuit to be interrupted during the last movement of the wire C and FI did not arise; no. Like the previous one, when the contacts C are closed again and (and the current S circuit switch / Q is turned off, the F coil circuit will not turn off and the switch will remain off.

The possibility of contact sparking from: due to the leakiness of their compression is also almost

eliminated by extremely insignificant;

time of current passing

equal only response time

- switch K.

The subject matter of the invention.

A device for open-ended opening of contacts of a contact measuring device used in installations for automatic temperature control or the like, in which the circuits of these contacts, before opening the latter, are automatically opened or bridged, characterized in that the circuit of the contacts controlling the switching coil F The automatic switch K, located in the circuit of the serviced receiver A of electrical energy (for example, heating resistance of the furnace), is turned on. It is connected parallel to this receiver, and the circuit of the contacts that control the switching coil E of the LH switch is connected parallel to the latter.