Cause : Brake chopper IGBT temperature has exceeded internal fault limit.

Let chopper cool down.
Check for excessive ambient
temperature.
Check for cooling fan failure.
Check for obstructions in the air flow.
Check the dimensioning and cooling of
the cabinet.
Check resistor overload protection
function settings (parameters
48.01...48.05).
Check that braking cycle meets allowed
limits.
Check that drive supply AC voltage is not
excessive.