Ask Our Experts

Ask Our Experts

Our Engineering Experts are asked a variety of question about filter sizing, power quality and product support. Here you will find some of our most commonly asked questions.

TCI offers a variety of options for the output of the variable frequency drive. Not always is long cable length the sole deciding factor for this selection. Yes, the output line reactor is a regular selection for 100 foot lead runs on a standard electric motor or perhaps using a drive on an older series motor. And yes, a V1K output dV/dt filter is typically a good selection for longer runs with properly sized lead cables and drive adjustments for either a standard or inverter duty motor.

The question then becomes, when do I actually suggest specifying the sine wave filter? There are some important questions for the customer to answer: what level of motor protection do you need, and what is the true cost of a premature motor failure and down time? Can you afford to have youe equipment down?  Can you get replacement equipment quickly? Can you get equipment replaced or repaired fast? Will you lose product or money during the downtime? Is it easy to fix when the motor fails?

The added cost of using the sine wave filter gives the customer longer motor service life and helps to reduce premature motor breakdown on drive applications. The sine wave filter returns the modulated square wave coming from the drive to a near sinusoidal waveform the motor really wants to see. That will reduce motor heating, audible noise, vibration and help reduce drive related motor insulation breakdown issues. It also reduces common mode currents and motor shaft bearing problems.

These benefits will keep submersible pumps moving water, HVAC fans and blowers heating and cooling buildings, irrigation pivots growing crops, and conveyors moving sand, gravel, or parts in a factory. Let’s not forget todays big topic of pumping gas and oil to support our economy and energy needs.

The sine wave filter will help reduce total operating costs by helping to keep drive systems running. TCI offers both the MotorGuard and MotorShield sinewave filters. Be a helpful consultant and quote a filter for those important drive applications. And remember, motor lead length is not the only issue for selecting a sine wave filter. For assistance, call your TCI Representative or TCI Technical Support to discuss your application requirements.  

Our team uses basic system data to generate accurate harmonic and power quality analysis for your unique application. By knowing the VFD horsepower, rectifier type, number of non-linear loads and drive impedance, we can provide an accurate active filter recommendation. We also provide a free, easy to use online sizing tool to help you set performance targets for harmonics and power factor. To access our online tool, Click Here.

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