Wet Patches in Varnished Insulation in Motor

I don't know, but the first four possibilities that come to mind:

• is it varnish from the windings? (with all power off and locked out, can you get a sample (or even just touch it)--is it sticky to the touch?) (Maybe the varnish wasn't baked properly--but that seems unlikely if it's been two to six months since the motor was put in service--or, are you saying, this happens with replacement motors as well, and only after 2 to 6 months in service? What happens then--do the motors die and need to be replaced? Are they big enough motors to be considered for rewind / repair--if so, what can the motor repair shop tell you? (wet varnish seems unlikely, because after two months, the varnish should be baked pretty good from the heat of the motor running--likewise, even if the varnish is a two part expoxy and somebody left out the hardener, I would expect the heat of the motor to have hardened it)
• is it condensation--is it a high humidity area? (this seems unlikely, as the motor heat will tend to prevent condensation)
• was there any kind of "silicone grease" applied to the terminations or contained inside those glass fibre sleeves when they were installed?
• is it leakage (into the motor) of some fluid in the process--or some lubricant used on other machinery in the process?
  

hi

greetings from India

do you have stored motors for long time before use?

because of humidity moisture is formed over glass fiber sleeves during storage period.

quality of glass fiber sleeve i.e. insulating varnish over the sleeve may be of air dry type which catches humidity if not treated properly

to prevent this clean the existing sleeve with solvent.

apply DR BECK backtol RED over the sleeve and allow some heat and dry cycle for curing.

you must pre-heat the motors before initial use.