Am trying to restore and antique theater popcorn popper that has a burned out heater. This is a 230 volt element and I wonder if anyone has found any place that sells just the coil element that I could use as replacement. Was thinking of a clothes dryer element also. thanks. Dale
Not sure what the shape is supposed to be but I would check out Johnstone supply they carry electric range elements as well as dryer ones. They have pictures of them so hopefully you can find one that matches the shape you need!
Wayne
According to dale :
Conceptually, it's not too hard to get it operational again, but given you call it an "antique", and "antique" implies that it could be _VERY_ old and unsafe (ie: no thermal cutouts etc), I'd be very nervous about it. Be sure to have a safety kill switch and a fire extinguisher handy...
If the existing element has one or two breaks, you can often get them brazed or silver-soldered to give it a few more years of life.
Alternately, if you can determine the wattage and dimensions of the existing coil element, you may be able to find a clothes dryer element that has the right wattage, roughly the same coil length and diameter, and cut it out of the element frame (if the frame can't be reworked to fit) to get to the raw coil and restring it.
It's also possible to make your own heating elements from raw nichrome, but that will require considerable care in ensuring you get the final temperature right. A really good appliance service center might be able to do that.
If you can't braze the existing element, I'd take the unit into a good appliance service center and ask if they can match the voltage, wattage, and length parameters.
How many watts is this thing anyway? Dryer elements are in the
4500-6000W range - that seems a trifle high even for an industrial-duty popcorn maker.
If you need to know the wattage measure the two pieces of old element with an ohm meter and then do the math.
A handy calculator :
According to PrecisionMachinisT :
Ah, to a certain extent, yes. But if you try to shorten the length dramatically while keeping the same voltage, you'll probably burn out the element. Even with active and tightly coupled thermostatic control (an "antique" may not have such a thermal cutout let alone thermostatic control) the lifetime will probably be dramatically shortened.
Heater wire has a positive temperature-resistance coefficient. Which means, as the temperature goes up, the resistance does too, _tending_ to self-regulate power consumption and keep the temperature constant even with reasonably minor voltage variation. Which means that the cold resistance is often very much different than operating resistance, and depending on the composition of the heater wire, the old coil might have the same resistance as the new coil when cold, but have radically different resistance at operating temperatures.
[Tungsten lightbulb filaments do the same thing, but not as dramatically as traditional nichrome heater wire.]The best way to measure operating resistance (assuming nowhere on the device is a plate saying what the wattage is) is to somehow get the breaks fixed temporarily, fire it up, measure operating current, and do the resistance calculation _then_. But keep in mind that's the hot resistance, not cold.
Reducing the length of a dryer element is presuming that the dryer wattage is _lower_ than the corn popper (unlikely). Halving the length of the dryer element doubles the wattage and quadruples the heat output per inch (assuming constant resistance, which it really isn't, but...). Given how they engineer these things with relatively close design tolerances (higher wire guage costs money), I'd expect the lifetime to be shortened no matter how good (the likely non-existant) thermostatic control is.
So, the most convenient yet reasonably inexpensive method of replacement would be to find a dryer element that roughly matches in length and wattage.
If it turns out that the OP can only find a dryer element with double the wattage and roughly double the length, he could cut it in half and rewire the corn popper for 120V.
He could probably obtain the nichrome wire himself and wind his own heater coil easily enough. I'm _sure_ there's web sites that show you how to design heater coils using nichrome wire, ie: how to select wire gauge for given desired lengths, wattages and supply voltages. But I haven't looked for any such sites.
Chris,
Nice post.
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