The DMCR relay
DMCR relay
The DMCR Protection relay is the most complete safety solution for a transformer.
It protects your transformer by monitoring temperature, pressure, oil level and gas accumulation inside the tank.
Monitoring functions :
Temperature monitoring is done via a probe located inside the thermo well immersed in transformer oil.
There are two monitoring levels: an alarm level and a tripping level. Both levels can be set freely.
Temperature is constantly displayed on the relay thermometer.
DMCR as seen from above
Pressure monitoring is done through a pressure switch. This pressure switch is located in the upper part of the DMCR relay and it monitors pressure inside the tank on a 0.1 bar to 0.5 bar scale.
The tripping threshold of the pressure switch can be set freely. However, it is factory-set at time of order on a specially-engineered test bench, which is a guarantee for precision.
The oil level monitoring function of the DMCR relay allows the tripping of the transformer (or setting off of an alarm, depending on the user set up) if the level of oil is decreasing abnormally or if there is gas accumulating inside the transformer.
In the event of gas accumulation, it can be sampled through the bleeder and then analyzed.
Oil level / gas accumulation control float
Technical benefits.
DMCR offers 4 safety functions in one compact but solid product. Fitting and connecting a DMCR relay is easy.
The body of the DMCR relay is made of ultra-resistant plastic material and has been designed in such a way that oil level is visible all-round, at 360 degrees. It is also possible to check temperature settings at any time, without opening the relay.
The standard DMCR relay also has integrated magnetic protection, which is unique for this type of product.
It is simple: the oil level monitoring system is made of a REED changeover contact which is actuated by a magnet, located inside the level float.
Theoretically, a REED contact is sensitive to any magnetic field and can therefore trigger when subjected to a magnetic field other than that of the DMCR magnet. However, this would be an issue as such occurrence would cause tripping of the relay, despite the absence of any legitimate default in the transformer.
In order to avoid such problem, we have designed the oil level monitoring system carefully so that the REED contact is actuated by a powerful ring-shaped magnet which, in addition to actuating the contact, also acts as magnetic shield against external magnetic environment.
The integrated magnetic protection and the 360° oil level visibility are patented innovations.