Switch device comprising a monostable auxiliary switch coupled t

Details Switch device comprising a monostable auxiliary switch coupled t Switch device comprising a monostable auxiliary switch coupled t

1992-05-26

1994-06-21

Donovan, Lincoln

Electricity: magnetically operated switches, magnets, and electr

Electromagnetically actuated switches

Multiple contact type

335202, H01H 6702

Patent

active

053231325

DESCRIPTION:

BRIEF SUMMARY
The present invention concerns a switch device comprising at least one main switch adapted to change state after a transient opening or closing phase due to the action of an operating member and at least one monostable secondary switch adapted to change state temporarily during one of said two transient states.
Generally speaking, it is suitable for all systems employing a switch where it is necessary to detect and possibly to signal the transient opening or closing phase.
It is particularly suitable for implementing multipole switch devices for supplying capacitive loads in which the load current is first established through limiter resistors connected in parallel with main switches that are still open by auxiliary switches connected in series with the resistors, the main switches being then closed by an operating member which closed the auxiliary switches.
These switch devices are used in particular in installations where it is required to improve the power factor. They may malfunction due to ageing of the contact members.
The operating sequence described above is usually obtained by using an operating member which is connected to a solenoid armature and actuates the moving parts of the switches simultaneously. Because of different size gaps between the moving contact parts and the respective fixed contact parts of the two sets of switches, the same movement first closes the auxiliary switches and then closes the main switches which therefore operate initially at a reduced current and thereafter at a constant current representing steady state conditions.
When the solenoid is de-energised to disconnect the capacitive load movement in the opposite direction is imparted to the operating member and the main switches open first and, because the auxiliary switches are still closed, interrupt a virtually negligible current. The auxiliary switches provide most of the rupture capacity and this compromises the service life of the device because their rating is less well suited to this function.
The fixed and moving parts of the main switches are never opened or closed at full load and so they do not benefit from the erosion caused by the electrical arcs and their contact surfaces are progressively polluted which results in an abnormal increase in the contact resistance and sometimes failure of the main poles to close. The increased resistance may in turn disrupt the thermal equilibrium of the switch device, and in particular that of the auxiliary switch and the resistors.
For this type of application, an object of the invention is to provide a switch device operating as described above on closing but reversing the sequence of actuation of the contact parts of the main and auxiliary switches on opening so that the current is transferred reliably from the auxiliary switches to the main switches.
To achieve these results, the invention proposes a switch device comprising at least one main switch adapted to change from an open condition to a closed condition during a transient closing phase and from a closed condition to an open condition during a transient opening phase, said two phases being caused by respective displacements of an operating member, and at least one auxiliary switch comprising at least one fixed contact and one mobile contact coupled to said operating member by a mechanical linkage.
According to the invention, this device is characterised in that said mechanical linkage comprises a releasable coupling adapted to change from a coupled condition to an uncoupled condition during one of said transient phases and to return thereafter from said uncoupled condition to said coupled condition during subsequent passage of the main switch through the other transient phase.
Advantageously, said releasable coupling is of the stress-release type and is adapted to be released when the operating force transmitted to the auxiliary switch by the operating member of the main switch exceeds a predetermined threshold.
In a first embodiment of the invention said releasable coupling comprises resilient snap-fastener means

REFERENCES:
patent: 4281305 (1981-07-01), Weeks
patent: 4345225 (1982-08-01), Lemmer

Affiliated with

Also associated with

Rating

Switch device comprising a monostable auxiliary switch coupled t does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Switch device comprising a monostable auxiliary switch coupled t, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Switch device comprising a monostable auxiliary switch coupled t will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2223332