Infrared Heater control

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powerplay

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In front of a computer.
I know very little about infrared heaters, but someone asked if they could put a dimmer switch on the circuit to control temperature....i said probably not, then someone else told me that it required an impedance matched transformer..SCR's?? I'd appreciate anything you can tell me about what it would take to adjust infrared heater heat if possible...thanks again!
 
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broadgage

Senior Member
Location
London, England
Presuming that these heaters consist ONLY of an infra-red heating element without say a fan, then yes they may be controlled by a lamp dimmer and I have often done this on small installations.
A 1KW lamp dimmer does not "know" if it is connected to a 1,000 watts of lamps or to a 1,000 watt heater.

What type of infrared heaters are these ? if the type that emits a red glow as well as warmth, then a high powered dimmer can be a good idea.
Adjustment of the dimmer will alter the brightness of the light, and re-assure the user that the desired effect is being obtained.
Thermostatic control is not ideal for such heaters as the on/off cycling of the red light is displeasing.

In the case of heaters that emit no light, then although a dimmer would work it may be needless complication, and thermostatic control or manual switching in groups might be simpler.

Remember that in the USA most dimmers are 120 volts, and many infra-red heaters are 208, 240, or 277 volt. Dimmers certainly exist for these voltages but are less common.
 
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gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
110115-1043 EST

powerplay:

Both answers so far are good responses.

In any problem the fundamental subject has to be "what is the correct question to ask". You may not know what that question is. Thus, you may have to ask many different questions from different points of view to try to find that correct question or questions.

You need to provide more information about your infrared heater. In particular ---
Does it include anything more than just the resistive heating element?
What is the purpose of the heater? For example drying paint, or keeping people warm.
Is it in the floor?
Is it overhead directed at people?
How accurately is temperature to be controlled?
How is temperature to be monitored?

If phase shift control or a Variac is used you can have a stable non-cycling intensity. A cheap home type dimmer is a phase shift type of control. A Variac is an adjustable auto-transformer. Implicit in phase shift or Variac control is that the thermal time constant of the heater element is long compared to the period of one AC cycle.

A "bang-bang" servo is an on-off type of control. A mercury switch or bi-metal type thermostat would fall in this category. Generally you would see a sawtooth type of variation in the temperature. Here it is implicit that the controlling device's cycling time constant is long compared to the thermal time constant of the heater.

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kwired

kwired

Electron manager
Location
NE Nebraska
Depending on what kind of precision of control is needed there are solid state relays with full cycle switching output. You can drive it with a PID type controller and have a pretty precise control of the temperature of the heated area without any noticeable change in temperature.

These work great on process heating where a constant non fluctuating temperature is needed.

May be a little expensive for general room heating unless constant temperature maintenance is important, placement of temperature sensor(s) will be important in this case.
 
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