GAS-ACTUATED RELAYS BUCHHOLZ TYPE . The new Comem Buchholz relay is an assembly of two machined aluminium alloy castings that effect a perfect. GAS-ACTUATED RELAYS COMEM TYPE. The range: 2. BG 25 H. Weight kg. Minimum clearance to remove the mecanism from the body. Min. The Buchholz relay also takes over the function of an oil level indicator when there The MSafe® Buchholz relay impresses with its robust construction in which.

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A fundamental advantage achieved with the present invention is that a Buchholz relay has been provided which, without having to differentiate the production process, allows end users to choose the degree of sensitivity of intervention of the relay in the presence of oil currents.

The relay 16 according to claim 1, characterised in that said movable cimem device 33 is made of plastics.

Comem eBR – Buchholz relays (Pressure and flow devices) | ABB

Customer can then choose which side he prefers. The relay is usually constituted by a body obtained from aluminum alloy castings, inside which a supporting frame is placed for at least one movable device which comprises an upper floater and a lower floater for operating magnetic switches.

In this manner, the manufacturer can produce Buchholz relays without having to differentiate any of their components and leaving the end user the freedom to choose the intervention threshold in case of oil currents. Contact information What would you like to do?

Imprint Privacy policy Contact Suppliers Newsroom. Extra function reliability due to the use of solid-body floats In contrast to frequently used hollow floats, the solid-body floats used by the MSafe cannot fill up with oil and lose their buoyancy. Leakage current, arcing, flashovers, loss of insulating liquid or excessively high flow rates can generate gas and affect transformer performance. The gas sampling device has been designed to overcome this problem by siting the unit remote from the Buchholz and in a readily accessible position typically on the side of the transformer.

Accessories for the Buchholz Relay: I need more information ABB Sales. Installation guidelines The following table gives guidelines values: For the sake of standardisation the device is fitted with the left and right hand valve supports but only one valve.

Search Expert Search Quick Search. Therefore it is the aim to ensure an accurate assessment of the transformer condition.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Likewise, the presence of strong oil currents is certainly due to the occurrence of severe faults with excessive gas production or, in other cases, to the presence of short-circuits or leaks in the tank of the transformer. Another object of the present invention is to provide a Buchholz relay which.


Inside the relay 16 there is provided a frame, preferably made of plastics, in an upward region whereof holes 26 are defined for engaging the cover 20 by means of fixing screws which are not shown in the above figures for the sake ccomem simplicity. The Buchholz relay must be applied at the highest point of the transformer and below buxhholz expansion vessel, which is commonly known as conservator, and must be filled with oil during normal operation. COMEM Gas relay is the right solution for detecting the internal gas generated by various phenomena like dielectric failure, slight overload and degradation of insulating oil.

As a routine test all castings are tested by injecting ambient air at 2. Navigate Search Login layouts-flyoutmenu-cart. An important advantage has in fact been achieved with the present invention, in that a Buchholz relay has been provided which can ensure excellent safety characteristics and most of all precision in setting the threshold of intervention when oil buchho,z occur.

Improved Buchholz relay – COMEM S.p.A.

Each one of guides 46 has, in the innermost end portion of its extension, a seat 47 which is suitable to accommodate the end 36 of the pivot 35 of the movable flap device This helium leak test guarantees maximum oil and gas leak proofness.

Any infringement will be legally persecuted. The collection coemm analysis of gases in an oil-insulated transformer can indicate the severity of the default.

Within the scope of cojem aim, an important object of the present invention is to provide a Buchholz relay which ensures good characteristics in terms of safety and most of all precision in the setting of the intervention threshold. The sides 39 are parallel and are kept together xomem a tubular support 40 which protrudes monolithically from them with an axis which is parallel to the pivot These gases can be used for a specific analysis to provide information on the status of the transformer or on-load tap-changer.

If buchhholz arc forms, gas accumulation is rapid, and oil flows rapidly into the conservator. The flow vent 9 has two permanent magnets.

The relay 16, in particular, is sensitive to the occurrence of oil currents whose flow-rate exceeds a preset limit which can be determined by the end user.

In other cases, the flap is adjusted by moving it appropriately along suitable guides or by using fixing screws, so as to reduce the surface of the flap that is affected felay the oil currents.

By staying here you are agreeing to our use of cookies. Another important functionality of the Buchholz relay is to operate if oil flow from the transformer tank to the oil conservator. Usually the flap must be adjusted appropriately relat as to be sensitive to currents in excess of a certain preset limit.


The relay 16 according to claim 1, characterised in that said movable flap device 33 comprises a tubular support 40 inside which a counterweight 41 can be inserted.


Each one of the switches 29 is of a per se known type and has, inside a bulb, a magnet and electrical contacts, not shown in the figures, which are directly connected, in this case, to an alarm circuit or to a disconnection circuit. For this test Messko uses helium ckmem its state-of-the-art test stand. Another important advantage has been achieved with the present invention in that a Buchholz relay has been provided whose configuration is simpler than in conventional types.

The movable device of the flap type 33 is preferably made of plastics. This relay responds only if oil flow occurs from the on-load tapchanger head to the oil conservator.

The terminal box cover 1 is fixed to the terminal box with 4 unloosable screws. The relay 16 according to claim 1, characterised in that mutually opposite guides 46 for the sliding of the buchhholz 36 of said pivot 35 are formed in said frame 25each guide 46 ending comej a seat 47 which is adapted for the snap insertion of said ends Said limit is usually set by standards or by the user, so that the manufacturer must produce different relays depending on the setting of the flap.

In some cases it is convenient to appropriately tilt the transformer in order to ensure that the Buchholz relay assumes the highest position on the transformer. There was a problem with your request.

Relay – Comem

A possible particular characteristic is that the contact of the disconnection circuit is kept closed whenever the flap rotates under the action of intense rellay currents or because the level of the oil has dropped below a certain value. In the upper part, the relay 16 is provided with a cover 20 from which a gas drain cock 21, a pneumatic test valve 22 and a grommet 23 protrude.

Protected Reed switches The reed switches of the MSafe are separated by immersion pipes from the oil. The identity of the gases being generated by a particular unit can be very useful information in any preventative maintenance program. Messko has had long years of positive experience with this material using it for the MTO series oil level indicators.

It is possible to detect hydrogen high-energy incident and carbon bucchholz aging of the insulation material quickly and reliably based on the colour change of the indicators that are integrated in the glass tubes.

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