Have replaced high votage transformer several times but it keeps burning out

What is the transformer being used for?

Same as above and what is the amp load vs. the amp rating of the low side.

Eb17bcoleman unit transformer on the air handler

Air handler normally doesn't have a transformer. It is 120 or 240 with a start or start/run capacitor. You question is a bit confusing. Heading says "low voltage" but body says "high voltage". Typically there is a low voltage transformer for the control panel and thermostat with a fan relay that closes and allows the 120 or 240 voltage through. Please clarify exactly what is happening.