SIEMENS CNC controls – SITOP power supplies

Stabilized power suppliesSITOP power supplies

The 24 V DC power supply units from the SITOP range are optimized for industrial use and operate on the switched-mode principle. Due to the precisely regulated output voltage, the devices are even suitable for the connection of sensitive sensors. Different versions are available depending on the output current and specific application.

In some cases, functional expansion is possible with add-on modules. For example, to protect against long supply system outages, 6 A, 15 A and 40 A DC UPS modules are available with external buffering by rechargeable batteries and maintenance-free SITOP UPS500 with capacitor technology. 48 V DC power supplies have been added to the SITOP product range.

The SITOP PSU400M power supply unit with 600 V DC input is suitable for use on frequency converters as an efficient DC/DC converter.

It converts the DC link voltage to a stabilized 24 V DC thus allowing, for example, specific emergency retraction movements to be performed in the event of a mains failure. This is possible because the control system and the drive electronics continue to receive a power supply for as long as there is sufficient energy stored in the DC link.

The wide DC input range (200 V to 900 V DC) and the high efficiency level (up to 96 %) ensure efficient use of the DC link energy. The compact power supply units are versatile in their application thanks to their high overload capability with 50 % extra power for 5 s/min, their comprehensive range of functions and their rugged construction. The selectable ON delay which ensures that the converter’s DC link is not loaded immediately during starting is one of the features that makes it ideal for operation on SINAMICS frequency converters.


  • High level of efficiency
    The efficiency of up to 96 % keeps the current consumption low and the control cabinet cool.
  • Easy installation
    The low weight and mounting accessories support fast and therefore low-cost installation.
  • Low space requirements
    The high power ratio means that the devices only require minimal space in the control cabinet and in the machines.
  • Accurate output voltage
    The output voltage of 24 V DC remains accurate even under conditions of extreme voltage variation. The loads are protected from overvoltage spikes which lengthens the lifetime and reduces downtimes.
  • Low residual ripple
    The low residual ripple of less than 0.4 % supports voltage-sensitive loads.
  • Integrated short-circuit protection
    No additional protection of the cables in the 24 V DC circuit is required.
  • Safety isolation
    The UA output is electrically isolated from the input (output voltage SELV acc. to EN 60950). Dangerous voltages cannot arise due to electrical isolation at the output.
  • Meets the requirements of national and international standards, e.g.:
    • CE marking in accordance with 89/336 EEC und 73/23 EEC
    • UL/cUL (CSA) approval
    • FM approval (Factory Mutual)
    • Marine approval
  • No release of silicone