Iwant to vary the power of heating element from 3.3kw to about 2kw.
This is use in tube sealer where the current draws is 27 amp, voltage of 9v ac.
I can use 30 amp thermostat 2-pole to vary .

Are you sure about that power consumption? 3.3 KW at 9 volts?? P=EI --> I=P/E=3300/9=360 Amps.
Seems a rather high current to me!
But if that power consumption at that voltage is correct (an industrial application perhaps) look into the possibility to reduce the voltage slightly.
If the power transformer has taps, switching to 7 volt reduces the power consumption to 2 KW. If there are not taps, may be you can make such a tap. The transformer secundary wiring must be gigantic and therefore easily accessible!
;)

Are you sure about that power consumption? 3.3 KW at 9 volts ??? P=EI --> I=P/E=3300/9=360 Amps.
Seems a rather high current to me!
But if that power consumption at that voltage is correct (an industrial application perhaps) look into the possibility to reduce the voltage slightly.
If the power transformer has taps, switching to 7 volt reduces the power consumption to 2 KW. If there are not taps, may be you can make such a tap. The transformer secundary wiring must be gigantic and therefore easily accessible!
;)

Thanks for your reply. I have to change my user name.
The element is 3.3 kw, draws a current of 27 amps with a secondary voltage of 9v ac and primary voltage of 110v controlled by a sealing timer.
This is use as tube sealer good for smaller tube. Now Im running a bigger tubes with this
3.3 kw with more time set it will ony burn my silicone tape on top of the element causing a bad seal to tubes.
That's why the only way I think is to reduce the kw of the element, not just reducing the voltage to 7v,note that the element draws 27 amps at 3.3 kw no matter how you reduce the volts still require a 27 amp.So I think of a 2pole thermostat that can handle high amps.Or anydevice to control or vary the kw of the element.

Thats why the only way i think is to reduce the kw of the element, not just reducing the voltage to 7v
Incorrect! The only FIRM value is the resistance of the heating element.
At P=3300 Watt and E=9 Volt that means an I of 3300/9=367 Amps, and a resulting resistance of 9/367= 0.0245 Ohm. That is the only fixed parameter!
The power consumption is a function of Voltage times Current times Time (duty cycle). If you lower the voltage from 9 to 7 volt, the current also decreases, as I = E/R = 7/0,0245 = 285 Amps.
And 285 Amps at 7 volt results in 285 x 7 = 1995 Watt (what you wanted).
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It is very difficult to control currents of 367 Amps. Soon the relay or other switching contacts will wear out (within hours).
The cheapest and best way to limit the power of the heater element is reducing the secundary voltage of the transformer.
The alternative to that is to control the power in primary winding of the transformer.
A thermo switch at the heating element controls than a power relay switching the primary winding of the transformer on/off.
Note that this still is controlling a considerable current : 3300 / 110 = 30 Amp, still too high for reliable operation of the system, and producing a continuous varying temperature at the element.
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Another alternative is to use an inductive current controller in the primary wiring to the transformer (as you do with a speed controller of a drill, but than one made specially for high current inductive loads (30 Amps min.).
You have to manually set that one, to reach the correct temperature.
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Personally I advice to open up the transformer and find a point on the secundary winding that provides 7 volt. Must be easy to do that. If you fear to do that go to a transformer repair shop, and let them do it. In that case ask them to provide 6, 7, and 8 Volt taps, to give you more regulatory capacity.
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Power the heater from zero and the new 7 volt point, and you produce a constant 2KW of heat at the element.
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Success!
:)