Unplanned shutdowns of parts of the installation lead to production losses and equipment damage, endanger process reliability and the quality of the goods to be produced. It is therefore important to use suitable protective devices to interrupt the power supply only in the event of actually existing fault currents. Furthermore, incipient residual currents should be detected at an early stage. Only those who keep an eye on their electrical installation can react in time without the protective device switching off. The high currents and/or high voltages generated during resistance welding often mean that conventional RCDs/residual current devices (such as RCCB, RCBO, CBR) cannot be used.
The short, pulsed and extremely high load currents and the system-related high-frequency leakage currents lead to false tripping and thus to unnecessary interruptions. Furthermore, conventional RCD solutions cannot be optimally adjusted to the installation.
The use of a residual current device (RCD) is often prescribed by standards for different protection goals, e.g. as protection against indirect contact or as additional protection in earthed systems. In resistance welding according to DIN EN 62135-1 (VDE 0545-1) or IEC 62135-1, a residual current device (RCD) can be used for protection against electric shock in the event of a fault (indirect contact):
We recommend the use of a modular residual current device (MRCD) according to DIN EN 60947-2 Annex M or IEC 60947-2 Annex M. Depending on your installation and your individual needs, we currently offer two product lines:
MRCDB300 series → The integrated solution: Evaluation unit and current detection unit are combined in one device. The devices have a communication interface for parameter setting and transmission of the present status and the currently measured values.
MRCDB423 → The combined solution: Evaluation unit and current detection unit are separated from each other. The evaluation unit with display enables direct parameter setting and allows direct reading of the actual status on site.
You gain flexibility. Modular residual current devices (MRCD) from Bender can be fully adapted to your application. Not only can the size of the external measuring current transformer be selected according to the conductor cross sections and the load current, but also can response values, response times, relay behaviour, frequency response etc. be individually adjusted to your installation.
False tripping is avoided. Due to the very precise measurements and the resulting much smaller tolerance range during tripping, your resistance welding system remains available for longer. Conventional RCD solutions can already trip at 50 % of the response value, the Bender MRCD trips at 65 % at the earliest, normally only at about 85 %.
False tripping caused by external influences such as high load currents from nearby cables are reduced by the optionally available magnetically shielded measuring current transformers. The MRCD from Bender also offers an adjustable filter function for frequency ranges and allows you to use existing circuit breakers.
Feel free to contact us – we will be happy to advise you. We are convinced that by using an MRCD you will gain flexibility, reduce unnecessary interruptions and use a residual current device that can be optimally adapted to the special requirements of your welding applications.
| Name | Category | Size | Language | Timestamp | D-/B-Number |
|---|---|---|---|---|---|
| Protection of persons, fire and plant protection, not an issue? | Technical information | 158.1 KB | EN | 2020/11/2424.11.2020 |
Products
AC/DC sensitive residual current monitoring modules for MRCD applications
Modular residual current device type B for additional protection (protection against indirect contact) in earthed systems (TN and TT systems)
AC/DC sensitive residual current monitoring modules for MRCD applications
Modular residual current device type B for additional protection (protection against indirect contact) in earthed systems (TN and TT systems)
