Korndörfer autotransformer starter (English Wikipedia)

The IEEE paper, Farr, L.B.; SmithIII, A.J. (2005). "Medium-Voltage Reduced-Voltage Autotransformer Starter Failures—Explaining the Unexplained". IEEE Transactions on Industry Applications. 41 (2). Institute of Electrical and Electronics Engineers (IEEE): 502–506. doi:10.1109/tia.2005.844396. ISSN 0093-9994., identifies the prior art auto-transformer Korndörfer circuit as a producer of fast rise-time voltage surges during a random transition from the first starting stage.
Emam, S.E.A.; Amer, A.H.; Gaber, M. (2008). "Protective measures for transient overvoltages in motors starting by autotransformers". 2008 12th International Middle-East Power System Conference. pp. 503–510. doi:10.1109/MEPCON.2008.4562397. ISBN 978-1-4244-1933-3. S2CID 44728880.
The IEEE paper, Gill, John D. (1979). "Transfer of Motor Loads Between Out-of-Phase Sources". IEEE Transactions on Industry Applications. IA-15 (4). Institute of Electrical and Electronics Engineers (IEEE): 376–381. doi:10.1109/tia.1979.4503676. ISSN 0093-9994. S2CID 17307995., provides evidence to the danger of using “Open Circuit Transition” in the reduced voltage Autotransformer motor starter apparatus.

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US patent 1096922A, Max Korndörfer, "Method of and apparatus for starting alternating-current motors", published 1908-05-15
US Patent 1840093, L.C Hardesty
US Patent 1561017, W.E Paul

Emam, S.E.A.; Amer, A.H.; Gaber, M. (2008). "Protective measures for transient overvoltages in motors starting by autotransformers". 2008 12th International Middle-East Power System Conference. pp. 503–510. doi:10.1109/MEPCON.2008.4562397. ISBN 978-1-4244-1933-3. S2CID 44728880.
The IEEE paper, Gill, John D. (1979). "Transfer of Motor Loads Between Out-of-Phase Sources". IEEE Transactions on Industry Applications. IA-15 (4). Institute of Electrical and Electronics Engineers (IEEE): 376–381. doi:10.1109/tia.1979.4503676. ISSN 0093-9994. S2CID 17307995., provides evidence to the danger of using “Open Circuit Transition” in the reduced voltage Autotransformer motor starter apparatus.

The IEEE paper, Farr, L.B.; SmithIII, A.J. (2005). "Medium-Voltage Reduced-Voltage Autotransformer Starter Failures—Explaining the Unexplained". IEEE Transactions on Industry Applications. 41 (2). Institute of Electrical and Electronics Engineers (IEEE): 502–506. doi:10.1109/tia.2005.844396. ISSN 0093-9994., identifies the prior art auto-transformer Korndörfer circuit as a producer of fast rise-time voltage surges during a random transition from the first starting stage.
The IEEE paper, Gill, John D. (1979). "Transfer of Motor Loads Between Out-of-Phase Sources". IEEE Transactions on Industry Applications. IA-15 (4). Institute of Electrical and Electronics Engineers (IEEE): 376–381. doi:10.1109/tia.1979.4503676. ISSN 0093-9994. S2CID 17307995., provides evidence to the danger of using “Open Circuit Transition” in the reduced voltage Autotransformer motor starter apparatus.