What's inside? - Maytag Neptune Door Lock Wax Motor.

[AJ]

Sometimes I like to take things apart just to see what's inside. 

Here are some photos of what's inside a Maytag Neptune Door Lock Wax Motor.






Motor - Wax, part number: AP4026523





Board, Control, part number: AP4026827

[BrntToast]

Sometimes I like to take things apart just to see what's inside.  <--- something i'd much rather hear from a tech than a customer calling to ask to have it fixed   

[apptech]

Sometimes I like to take things apart just to see what's inside.  <--- something i'd much rather hear from a tech than a customer calling to ask to have it fixed   

I hear ya there. 

[shieldcracker]

Is that disc on top of the rectangular wax pot the resistor that heats the wax?
Or is it the metal pot case that acts as a resistor and the disc a overload device.

[JWWebster]

dang good qwess shield, Maybes one day we will know

[Repair-man]

Here's the skinny...the round disc is cemented to the  plunger assembly with thermoelectric glue, much like the paste used on Uline icemakers to hold the mold to the coldplate. It is there to keep the plunger in a fixed position so it does not float around in there and short out. The other side of the disc contacts the L1 terminal. The metal plunger housing is  positioned very close to the opposing Neutral terminal, creating enough of a gap where it does not short out completely yet close enough to create heat from the 120 volts. The whole cavity of the plunger is filled with a waxlike substance which expands when heated. The spring is there to keep it from jumping out too fast and also to help it retract faster when it cools down.

any questions?

[Mr. Fix-It]

How is heat being generated without a complete circuit? Where's the circuit load that creates the heat?

[Repair-man]

Actually, there is a complete circuit...thru the shiny metal encapsulated plunger assy. Notice on the top photo how each terminal touches it, one thru the round disc, the other on the lower side. The whole capsule is filled with wax which expands when the plunger housing is hot.

[RegUS_PatOff]

The "disc" is a PTC resistor...

A thermally conductive adhesive is used on each side ...

Each with substantially different properties of electrical conduction.

After reading the following,
I can't imagine why they would fail ...

http://www.freepatentsonline.com/7157670.html
(scroll down)

[Mr. Fix-It]

Ah OK the disc is the load then I see. It looked like it was just a hunk of metal. That clears that up. Frightening design though.

[shieldcracker]

It took a while for the answer to come in! I have another question, is the device rated for 120 volts?

[Repair-man]

Well, yes it is designed specifically for 120volt operation. The other switches it  pushes against are both high and low voltage. The Lock light switch, for example is 120 volts also, the spin enable switch is 24 volts.