PULS UK, a manufacturer of high efficiency DIN-rail power supplies, has introduced the QTD20.241 DIN-Rail power supply for use with ac motors and drives. At only 65mm wide, and offering 24VDC at 20A, this 95% efficient Din-Rail power supply uses existing system power to provide secure dc for control systems.
Modern machines typically use maintenance-free ac motors that are controlled by frequency converters or servo amplifiers. Such controllers have an intermediate dc-bus to which all individual drives are connected.
The PULS Dimension QTD20 power supply can be connected directly to the intermediate dc-bus, removing the need for a separate mains or low voltage supply for control equipment.
In the event of a mains failure, the QTD20 utilises the power from the dc-bus capacitors, which are charged from the kinetic energy of the motor until the motor has come to a complete stop. This ensures that the control equipment and other important peripheral equipment is kept operational long enough for a controlled shutdown to take place.
Intermediate dc-buses are not usually filtered, and have high EMI noise superimposed. The PULS QTD20 has a very robust input stage with an appropriate input filter included. Additionally, the QTD20 is UL 508 approved, and is equipped with input fuses rated and tested for 600VDC applications.