used stir plate question

i was given a used mag-mix stir plate from a friend recently. I've used it once, but the thing gets really hot and i'm a bit worried.

I took it apart and everything appears to be properly attached and wired but the potentiometer appears to be the thing getting hot. Is this normal? I know it controls the power transferred, so it makes sense that it would get hot, but this seems really hot.

Do potentiometers go bad?

Do i just put a silicone hot pad on the stir plate to keep the heat from the yeast and not worry about it?

any insights would be appreciated

How hot is it getting? If it's under 100F then I wouldn't worry about it.

hot enough that it's uncomfortable to the touch. i put a thermometer on it last time, but i can't remember if it was 100 or 110. I'll do some tests later and see. Part of it was that i stopped using it when it got that hot because i was going to bed and feared it would continue to heat up and cook my yeast

If it's so hot that you can't keep your hands on it then it's around 110-115F, that's a bit too warm for my tastes. AFAIK a lot of commercial stir plates have heat built in, not sure if this is one of those but I've not heard of a pot getting hot like you are describing. If it is in fact the pot, I'd try to find a replacement.

Donner said:

i was given a used mag-mix stir plate from a friend recently. I've used it once, but the thing gets really hot and i'm a bit worried.

I took it apart and everything appears to be properly attached and wired but the potentiometer appears to be the thing getting hot. Is this normal? I know it controls the power transferred, so it makes sense that it would get hot, but this seems really hot.

Do potentiometers go bad?

Do i just put a silicone hot pad on the stir plate to keep the heat from the yeast and not worry about it?

any insights would be appreciated

Click to expand...

It's possible that the component has gone bad, or it's possible that the part was underrated to begin with. If you are handy with a soldering iron, it should be easy enough to swap out.

I ran the plate without the cover on and it was clearly the potentiometer that was getting hot. Not sure how hot, but it makes sense that it would be heating up the whole unit.

I don't think it's designed to be heated since there is no second dial for control.

I think i can replace it easily enough, i just didn't know if it was normal for potentiometers to get so hot.

The casing says it's a 115 volts, so i assume i'd need one that would be rated that high.

It seems like a great stir plate other than the heat issue, so i think i'd like to salvage it if i can

Pots are rated for wattage, not voltage. You need to figure out how much of a voltage drop your circuit yields in relationship to the current draw of your motor, and then calculate a maximum watt rating from that.