Possible Stupid Question

Here it is... Is the coil supposed to have some sort of liquid in it. When I removed mine, when I shake it it sounds like there is water inside of it. :v6:

 

there are no stupid questions
I think it's oil of some kind
can't be more specific than that
sorry

 

X2, it is filled with oil.

 

X3 - Shell Dialla AX transformer insulating oil.

 

correct there are no stupid questions only dumb ones. j/k

 

Older coils (pre-1960) likely used PCBs. Modern replacements are a mineral oil. The oil conducts heat from the windings to the shell. IMO if you can hear it slosh, it probably has leaked some.

 

Depends on who made them, some will slosh when brand new, some won't, I have a brand new spare that has sloshed since new, my old Accel unit sloshed when I bought it, the one I run on my Jeep does not and it is a "Standard" brand oil filled not epoxy.

 

Just as a note: the older coils using PCB's (polychlorinated biphenols) are also filled with mineral oil. The Shell Dialla series was the most common brand used. PCB was an antioxidant oil additive which was later banned because of environmental and health concerns. This can be nasty stuff, so if you have an old coil that leaks, try not to get the oil on your skin, and dispose of it at a (free) county hazmat pickup point.

Most coils were designed with a dry-nitrogen "bubble" built in, to allow for oil ullage (expansion with heat). The liquid oil cannot compress, so a fully-filled coil would likely leak from the extreme hydraulic pressure of the expanding oil. Whether or not the coil sloshes depends on the size and location of the bubble.