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New to Electrical Design - Please Help

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Newbie level 2
Sep 11, 2009
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Boston, MA
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nichrome wire 120v

Ok, so I'm hoping this is a really simple question to answer (given that I'm missing lot of information) but as I said I'm new to all of this so I'd appreciate if it no one would flame me...

So heres the situation:

I have the guts of a popcorn popper (120v 1440w) which has 2 infrared heating coils tied in series (which I assume are Nichrome wire coils?) and it also has a small electric motor tied in parallel? (I dont have the specs of the motor with me but I can get them if needed) I dont know if this matters but it has a wheatstone bridge connecting the motor to the circuit (I dont know the resistance of each resistor but again can find it out if needed)

What I want to do is some-how cut the total heat output of the system down to a point where I can use a 600w 120v lighting dimmer as a rheostat.

Any information you could provide would be greatly appreciated. Thanks!

For your purpose, the motor and its connections should not matter. If you can make a electrical contact at any place on the heating element (to use as a rheostat), it should work. The wire beign hot, it is to be taken care of. Such arrangements are often used in arcs used in spectroscopy.

So if I understand you correctly:

I can shorten the heating element wire (by cutting it or simply connecting the Neutral to the heating element wire closer to the Line side) -- thus reducing the total resistance of the circuit? and allowing me to use a 600w rheostat?

To reduce the current from 12amps (1440watts) to 5amps (600watts), you either need to use a transformer to reduce the voltage coming from the wall socket from 120vac to 50vac, or you need to increase the resistance from the design value of approximately 10 Ohms to 24 Ohms.

You do NOT want to shorten any of the heating elements - that would decrease the resistance of the heating elements and increase the current. Just the opposite, you need to find an old heater and add some of the nichrome wire in series with the existing heating element to INCREASE the resistance. That will DECREASE the current, and the total power.

Ohm's Law: Current = Voltage divided by Resistance (I=E/R)
Power = Current times Voltage (P=IE)

Now to the practical issues - if you decrease the current in the heating elements to allow your dimmer to work, your machine will probably not get hot enough to pop corn any more.


I think that, there is no need for procure anything.

As per your statement, you have two heating coils connected in parallel manner. such as shown below.


Now just make the coil connections as series. as shown below.


Now your requirement going to be fullfiled.

Take care.

Hi, iam sorry.

as per your statement it self you told coils are connected in series. Iam not properly go through your statement.

In default for high watage applications heater coils connected in parallel manner.

Kindly follow House_Cat suggestion.


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