New current limiting feature for ignition protection
15 July 2011
Danfoss VLT Drives has introduced a new current limiting feature for its VLT AutomationDrive, which makes it easier to apply “Ex-e” motors instead of the more expensive “Ex-d” motors. The feature ensures that the VLT drive will limit motor current to prevent the motor from overheating. The user simply enters data from the motor nameplate via the drive's control panel, and from this data, the drive creates a “loft” that limits the current provided dependent on motor speed.
The new feature offers more than just an economical and flexible alternative to existing methods. It opens the way to attractive energy savings by increasing the cost effectiveness of speed controlled applications, especially pumps and fans. Features at-a-glance:
Uncomplicated - flexible use of speed control with motors having “Increased Safety” ignition protection
Compact - distinctly smaller frame size, lower weight and lower costs compared with speed control of motors with flame-proof enclosures.
Flexible - easy mix and match, resulting in smaller stocks of motors and converters.
Economical - lower investment costs enable faster payback when speed control is used to achieve energy savings .
Universal - universal application across the power range of 0.4 to 1,200kW with 400, 500 or 690V supply.
No need for matched pairs - suitable for operation of Ex-d/de and Ex-e motors without the need for matched pairs of motors and drives.
The VLT PTC thermistor card MCB 112 (which handles PTC thermistor monitoring), ensures that motors with Ex e ignition protection are operated in compliance with the provisions of ATEX Directive 94/9/EC.
Contact Details and Archive...