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POWER INDUCTORS
Notes to Figure 5 (Page 95)
The PT Toroid Series inductance is speci鏗乪d at AC and DC signal levels which have no signi鏗乧ant effect
on the permeability of the powdered iron toroidal core. Superimposed AC and DC voltages will change the permeability and therefore
the inductance, under operating conditions. Typically, DC currents will reduce the inductance, while AC signals will increase the
inductance up to a point, before beginning to decrease. Supporting information is provided, detailing the AC or DC effects upon each
part. Saturation resulting from DC currents is speci鏗乪d with waveform having less than a 1% ripple content. When considering the AC
waveform, both the frequency and voltage level must be taken into account. As an aid in de鏗乶ing what effect the alternating sine wave
signal will have, the voltage/frequency factor curve can be used. To determine what change of inductance can be expected at a given
voltage level and frequency, simply divide the sinusoidal RMS voltage by the frequency. The voltage is in volts and the frequency is in
hertz. As an example, if using part number PT25-680 at a 1VRMS signal level, and a frequency of 25KHz, the voltage/frequency factor
is calculated to be: 1VRMS/25,000Hz = 40 x 10鈥?. Referring to the graph, a 39% increase in inductance would be expected.
Notes to Figure 6 (Page 95)
Typical saturation effects as a function of DC 鏗俹wing through the part. Data is representative of a DC
waveform with less than 1% ripple, and an AC waveform less than 10 gauss.
Note
This information is intended to be used in assisting the designer in part selection. Each operating application may contain other
variables which must be considered in part selection; such as temperature effects, waveform distortion, etc.... Delevan Sales/Engin-
eering staff is available to provide information as needed to 鏗乼 each application.
www
.
delevan
.
com
E-mail: apisales@delevan.com
270 Quaker Rd., East Aurora NY 14052 鈥?Phone 716-652-3600 鈥?Fax 716-652-4814
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