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Decreasing Transformer Recovery Time

IP.com Disclosure Number: IPCOM000095205D
Original Publication Date: 1965-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Lake, JA: AUTHOR [+3]

Abstract

Non-linear elements are used to decrease the recovery time of transformers pulsed with unbalanced current bipolar inputs.

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Decreasing Transformer Recovery Time

Non-linear elements are used to decrease the recovery time of transformers pulsed with unbalanced current bipolar inputs.

When primary 1 of transformer 2 is pulsed with unbalanced bipolar current pulse 3, the voltage across secondary 4 is as shown at 5. The secondary current therefore assumes its maximum positive level when pulse 3 is first applied. The current then decays exponentially until the polarity of pulse 3 reverses itself. It now assumes its maximum negative level and exponentially decays until the end of pulse 3.

At the end of pulse 3, the current through secondary 4 assumes some small level other than zero. This is as a result of the differences in the areas of the positive and negative portions of pulse 3. This means there is residual energy stored in secondary 4 of transformer 2. Such residual must be dissipated prior to the application of the next pulse if a level shift is to be avoided. With only resistive load 6 on secondary 4, the dissipation of this energy would take an infinitely long time. However, by the addition of oppositely poled diodes 7 and 8 in series with load 6 and secondary 4, the energy level in transformer 2 is reduced to a negligible value in a relatively short time after the cessation of pulse
3. Diodes 7 and 8 allow the flow of current during pulse 3. At the end of pulse 3, the remaining small secondary current maintains diode 7 in a forward biased condition. Such occurs until the negative a...