I am currently working on evaluating the breakdown strength of dielectric paper using the standard sphere gap method under AC voltage, as mentioned in some studies. I would like to gain a deeper understanding of the entire setup and procedure. Specifically, I have the following questions:

• What type of testing machine is typically used for conducting breakdown strength testing using the sphere gap method? Are there specific models or brands recommended for high-temperature testing (up to 300 °C)?
• How is the sphere gap setup constructed? Are there specific materials or electrode sizes recommended for this testing?
• How is the AC voltage source controlled to maintain a steady rate of 200 V⋅s⁻¹, and what safety precautions are typically implemented?

• Are there any specific guidelines for preparing the dielectric paper samples, such as electrode placement or surface conditioning?
• Is it necessary to use electrodes like platinum (Pt) or silver paste (Ag) for ensuring uniform contact, or are other conductive coatings preferred?

• How is the temperature of the sample regulated during testing? Is a digital ceramic heater with a thermocouple sufficient, or are there other recommended temperature control systems?
• How is the alignment and positioning of the electrodes ensured to minimize errors in breakdown strength measurements?
• Are there any specific data acquisition systems or software recommended for recording breakdown voltage and current?

I would greatly appreciate detailed insights, references, or standard protocols for implementing this testing method effectively.

Thank you very much for your assistance and guidance.