40 A power supplies

Siemens has added a compact 40 A basic unit to its Sitop modular power supply series. It is 150 mm wide, which is 90 mm narrower than the previous unit. The 20 A power supply has also been renewed and is now 70 mm wide. The two Sitop PSU300M standard mounting rail power supplies for connection to three-phase 400-500 VAC networks now have a wider range input (from 320 to 575 VAC) than previous versions and they provide a reliable 24 V supply even when there are large deviations in the mains supply. The user now simply evaluates the ‘DC 24 V OK’ operating mode via an integrated dry signalling contact.

Apart from its small dimensions, the 40 A power unit can now supply 60 A for 5 s, so it can be used to switch on terminal equipment with high starting currents. Its efficiency of up to 93% reduces energy consumption and heat build-up in the control cabinet.

The Sitop PSU300M standard mounting rail power supplies also have rugged metal enclosures and can provide up to three times the rated current to meet short-term peak power demands. Short-circuit response can be set with the option of either latching shutdown or constant current with automatic re-ramp up to the output voltage. Used in combination with Sitop add-on modules, comprehensive protection can be achieved against primary and secondary disturbances.