MTE Corporation Announces New dV/dt Filters Design to Protect AC Motors

  • November 22, 2004
  • News
MTE Series A dV/dt filters are designed to protect AC motors from the destructive effects of peak voltages facilitated by long cable runs between the inverter and motor. Depending on the turn-on time (Semiconductor risetime) of the power semiconductors used in the inverter, and the size of the motor; cable lengths as short as eight feet can result in motor peak voltages that exceed the rating of the motor¡¦s insulation system. However, the longer the cable the greater the problem.The MTE dV/dt filter is guaranteed to meet its maximum peak motor voltage specification (150% of bus voltage) with up to 1,000 feet of cable between the filter and the motor. It is also rated for a maximum dV/dt of 200 volts per microsecond. However, in specific applications, the filter has provided excellent performance with cable runs up to 3,000 feet. The dV/dt filter has a ¡§3% insertion impedance¡¨ which ensures motor torque is not affected by added voltage drops from the filter. The MTE dV/dt filter is a passive fourth order device that reduces transmission line effects of motor cables by dampening the rate of voltage increase and minimizes the peak voltage that occurs at the motor terminals. MTE Series A dV/dt filters are designed for use with inverters operated at switching frequencies between 900 Hz and 8 kHzThe dV/dt filter has a continuous current rating of 100% RMS and intermittent current of 150% for 1 minute and 200% for 10 seconds.Available as panel-mount or in NEMA 1, 1-2 and 3R enclosures the new dV/dt filter is rated for use in temperatures up to 50„a C as panel mount or 40„a C with enclosed cabinets.Typical applications include submersible pumps, HVAC equipment and process automation lines. Motors rated 100 HP and below and standard NEMA B motors, MG1Part 30, are prone to failure as a result of high voltage spikes and will benefit from dV/dt filtering.The MTE dV/dt filter is UL and cUL listed to UL508 and CSA-C22.2 No 14-95 File E180243 (3 ¡V 1000 HP, 120VAC through 600VAC 50. 50/60 Hz Three Phase).MTE Corporation offers a wide variety of power quality solutions designed to improve the reliability and performance of variable speed drive systems and to minimize interference with other sensitive electronic equipment. Products include the industry-leading Matrix Harmonic Filter, RFI/EMI Filters, line/load reactors, surge protectors, dc link chokes, motor protection filters and a wide array of power quality equipment designed to protect and lengthen the life of electric motors, motor controls and other critical equipment.MTE products are available and supported worldwide from factory offices/warehouses and through a network of Sales Representatives and Authorized Distributors.For more information visit:

Did you enjoy this great article?

Check out our free e-newsletters to read more great articles..