Thats what I thought but tested the Fluke meter.It's probably a capacitor.
That would make sense, I pulled it away from the windings while trying to troubleshot and has not failed but being in Az the ambient temp could be part of it. It is a couple of yrs old but just started, maybe getting weak. Not a lot of load as it is driving a pool led light.It is certainly a PTC thermal polyfuse p/n RHEF900 available at Digikey For <$2
But it seems to be working as expected on and off. What is uncertain is the ambient temperature and what loads have increased causing it to switch off. The critical uncertainty is your threshold temperature. If it is getting almost too hot to touch. It's your excessive load.
Define your loads please. The surge and power stored is causing your symptoms.
It is rated to hold 9A <=16V RHEF900 = H9 16V - High Temperature
Tony Stewart there is no room for a fan. Worked all afternoon yesterday (ambient ~80°), turned it on for an hour then off for a bit then back on w/o fail.I don't have a lot of details but if it is getting hot, a little 12V fan might make it happier, retrofit to maximize the air velocity across the surface.
On second thought, 120VAC/14VAC 70VA hmm probably makes 12V to 14Vdc for about 50W max. You might be able to see if your pool lights run on 12Vdc or a car battery. These supplies are cheap and almost free if you find an old PC power supply.
We still do not know exactly what lamps (link parts) nor the transformer temperature to properly analyze the cause.Tony Stewart there is no room for a fan. Worked all afternoon yesterday (ambient ~80°), turned it on for an hour then off for a bit then back on w/o fail.
This morning (ambient ~50°) I turned it on light came on for brief moment then turned off. Turned power off for a bit then back on and same thing happens.
Ordered replacement poly-switch from Digi-Key with part# Tony Stewart posted.