The more universal a system is designed to be, the more important it is to be suitable for use in many different applications. This is also the case with the SINAMICS G120C - the compact converter system from Siemens - which is used as a universal drive for all industrial and commercial application areas. Target industries include HVC (heating, ventilation, cooling), automotive manufacturing, textile, printing, and the chemical industries as well as cross-industry applications such as material handling or building systems.
Depending on the application, sometimes the devices in the power supply network operate within the IT network configuration (French: Isolé Terre). Siemens has therefore made sure that all their component solutions meet the special requirements of IT networks. For power connections, Weidmüller offered the best plug-in connector solution in the shape of its OMNIMATE® IT range.
A single insulation fault produces no dangerous contact voltage in IT networks. The reference potential earth is at the same voltage level as the faulty phase.
Full power for IT networks
Energy supply networks in the IT network configuration (also known as the 3-wire system) are found in production lines in the automotive industry, hospital operating theatres, trains, mobile generators, and special industrial facilities, like those found in explosive hazardous areas - in mining, for example. IT networks have specific features which Weidmüller fully took into consideration when designing its OMNIMATE® IT PCB plug-in connectors.
“A single insulation fault produces no dangerous contact voltage in IT networks. The reference potential earth is at the same voltage level as the faulty phase,” explained Wolfgang Sichmann, product manager at Weidmüller, about the IT network’s characteristics.
“A second insulation fault on another phase results in the safety fuse being tripped. For this reason, there are special fault alarm systems used that warn on the first earth fault so that troubleshooting can be done before a shutdown occurs.The system is ‘first-fault protected’ in this way. In order to comply with IEC 61800-5-1:2007, IT mains systems must account for 400 volts relative to earth. The touch protection gap thus increases from 3 mm for 400-V TN networks to 5.5 mm for 400-V IT networks. These enhanced requirements are fully met throughout our OMNIMATE® IT range. Even the SU 10.16 IT MF male header with its large plug opening for PCBs in 10.16 mm pitch, offers sufficient basic touch protection with its insulated contact tips.”
There are three product families in the OMNIMATE® IT line; they are SL/BL 7.62 IT MF, SV/BVZ 7.62 IT MF, as well as SU/BUZ 10.16 IT MF. These are scalable from 24.5 A/2.5 mm² through 41 A/6 mm², up to 76 A/16 mm², and operate equipment in the power categories up to 16 kVA, 28 kVA, and 52 kVA. The same design is used for all three sizes of the SINAMICS G120C, which is ideal for Siemens, as the company wanted uniform plug-in connectors.
The middle flange saves space and acts as a one-hand, safety interlock mechanism. This guarantees that the male and female headers can snap together safely and automatically. The clearance and creepage distances of the PCB plug-in connectors have been optimised, so that even in difficult installation situations there are no restrictions placed by the UL approval for 600 V applications. The female headers can be delivered with clamping yoke (screw) connectors, where the terminal points are always open at delivery. This saves time and money when wiring and permits an automatic functional test of the device with the female header installed. Even the BVF 7.62 HP PCB plug-in connector with its PUSH IN connection technology meets the requirements of IT networks.
Standard-compliant, compact design, automatic locking, and time saving were the arguments that convinced Siemens to use the OMNIMATE® IT plug-in connector series. By using the OMNIMATE® product series, there is no requirement for additional covers in the SINAMICS G120C range of devices. The design-in and approval process also took place without any compromises.