Preliminary Analysis Turn to Turn Voltage During Impulse

Preliminary Analysis: Turn to Turn Voltage During Impulse. How to test to 50 V Turn to Turn? Trey Holik, Carlo Santini, Steve Krave QXF High Voltage discussion 11 March 2016

What Tests were performed? • Practice coil QXFP 01 b was Hi-Potted and Impulse tested – Passed all ‘nominal’ electric tests – Fabricated without VTs or PHs • Electrical tests to failure or equipment limit. • Holes were drilled at each turn for measuring T 2 T dc and impulse voltages. 2 Trey Holik| Turn to Turn Impulse Voltage 3/11/2021

Turn To Turn Impulse tests (all at 100 V nominal) • Oscilloscope data: 20 ns/sample, 5000 pts/impulse, 100 µs/impulse, 3 impulses/plot • Data averaged over 500 ns: Good balance between smoothness and maintaining voltage shape • Direct polarity has L 1 at ground, Reversed polarity has L 2 at ground Direct Polarity 3 Trey Holik| Turn to Turn Impulse Voltage Reversed Polarity 3/11/2021

First Peak – Region of interest • Voltage of each turn during a nominal 100 V impulse • The plot is of the first peak • What we want: What is the voltage between each plot/line? ? ? L 2 4 Direct Polarity Trey Holik| Turn to Turn Impulse Voltage L 1 Reversed Polarity 3/11/2021

Peak voltage between Turns (Direct Polarity) 5 Trey Holik| Turn to Turn Impulse Voltage 3/11/2021

Peak voltage between Turns (Reversed Polarity) 6 Trey Holik| Turn to Turn Impulse Voltage 3/11/2021

Summary • Since the dphi/dt area is smallest at the pole turns it will require ~5000 volts to create 50 volts between pole turns • Adjacent turns for L 1 pole turns will require ~3500 volts • Adjacent turns for L 2 pole turns will require ~4000 volts • Midplane turns will require ~1200 volts • A 5000 volt impulse will place 210 volts at adjacent midplane turns 7 Trey Holik| Turn to Turn Impulse Voltage 3/11/2021