Johnny's Reloading Bench PID Controller Help

[flygrimm]

See the post above for the measurements. I bought the pot new several years ago but have only used it a few times.

Stuart

[Delkal]

With the multimeter set to 200 ohms I am getting a reading of about 20 between the terminals of the heating coil. I am getting a reading of about 14 between each terminal and the case of the melting pot.

I took the PID out of the equation for the next test. When I plug in the pot directly into the wall outlet the pot comes on and I can touch it without any problem. Once I ground the case of the pot it trips the GFCI.

Does that mean the pot measurements were when it was plugged into the PID? I was asking for the numbers of just the pot unplugged. I have no explanation for how you can have unity from each plug to the case and not have it short out immediately when you plug it in. I have no idea about your pid circuit and if the readings are normal or if it is from the ground fault circuit being very sensitive but you claim you got shocked. There shouldn't be enough voltage downstream of the PID controller to do that.

[flygrimm]

The measurements were taken with the pot unplugged from everything.

Stuart

[Delkal]

My pot is 3 pronged and the ground plug is attached to the body and tested under 1 ohm as expected. The ohms between the other two plugs is 20 ohms as expected from going thru the heater coil. Neither of these plugs give any readings when touched to the body so they are isolated. I have no other ideas about what is going on. Sorry.

[flygrimm]

Thanks for your time. I'm going to give Lee a call. I'll let you all know what they say.

Stuart

[Delkal]

Since you had the top of the melting pot open check the connections again and make sure none of the connectors are touching the body. I am not sure what that connector on the right of your photo is for but make sure it is far from the body and any other wires when you put the top back on. Good luck.

[flygrimm]

Just talked to one of the techs at Lee. He thinks that the insulation on the outside of the coil had broken down and is causing my issue. He said that I should not have any continuity from either terminal of the coil and the outside of the coil. I do remember that when I took it apart initially to install the thermocouple there was a bunch of rusty junk in the bottom of the housing. That's probably the insulation he was talking about.

I'm going to order a new coil and see how that works out. I'll test it out with the multimeter before I install it as well.

I'll let you know how things go.

Stuart

[flygrimm]

OK. Got back from work with a package from Lee. I did a few tests on the new vs old heating element.

IMG_2397.jpgIMG_2398.jpgIMG_2399.jpgIMG_2400.jpg

First picture shows the resistance of the old element at around 20 ohms. Second shows the resistance between the core of the old element and the outer covering at around 30 ohms.

The third shows the resistance of the new element around 20 ohms again and the fourth shows the resistance between the core and the outer cover is an open circuit.

I installed the new element and now when the metal covering from the thermocouple touches ground nothing happens! New element works well and no more shorting out.

[Delkal]

Thanks for posting a followup. First time I heard of that and something to keep an eye out for in the future.