Claude Lyons Variac Refurbishment

Part 2 - Initial testing, cleaning and assessment of condition.

The Video

View this video on Youtube.


In this video, the electrical connections are explained, and several tests done to ensure the device is still safe working as intended.

The transformer windings are intact, however the carbon brushes are excessively worn, resulting in a high resistance.

Insulation resistance is checked between the windings and the metal frame.


Output voltages are checked, and they can be varied between 0 and 100% of the input voltage. Voltages on the fixed taps are also checked.

Wiring connections between the terminal plate and transformer are examined, the brushes are checked, and the top tracks on the transformer are cleaned.

The rotary plate has a substantial amount of paint loss, and the internals are very dirty.