Assertion: tube | /r/CapableOf | turn on with slow ramp
Facets:
value: to avoid thermal shock
type: PURPOSE
Source sentences:
text: Further measures included switching off the heater voltage when the tubes were not required to conduct for extended periods, turning on and off the heater voltage with a slow ramp to avoid thermal shock on the heater element,:226 and stress testing the tubes during offline maintenance periods to bring on early failure of weak units.:60–61