Can I use the same choke for use at the input or output of a drive?
We do not recommend this, as we believe this to be a compromise which leads to mediocre performance in either application.
REO build input chokes, Type CNW903, specifically for harmonic mitigation, transient suppression and general EMC use. These are usually of a higher inductance, than an output choke, for a given current, to ensure that the optimal harmonic reduction effect is achieved. Typically we manufacture inductors to give a 4% volts drop at the rated current, this level has been determined to provide the most cost effective performance although units with lower inductance are available. The laminations are standard thickness for mains 50/60 Hz operation as the voltage and other working parameters are well known.
On the other hand, REO’s range of Motor Chokes, Type CNW854 is designed and manufactured to operate between the output of a frequency drive and the connected motor. Its inductance is usually rated to give a volts-drop which will not unduly affect motor performance, but at the same time provide the dV/dt limiting and motor terminal voltage reduction. The core is designed to operate at a lower flux density as inductor performance is severely affected at saturation. The laminations are thinner in order reduce the eddy current losses which occur due to the increased range of frequencies applied to the choke in normal operation.← Back to FAQs