Selecting an scr controller for very small electric heater

[Finestein]

Hello everyone/anyone, this is my first post so bear with me.

I am trying to closely control the temperature of air moving slowly and continuously through a duct (~30cfm). I would like to use a very small (250-350W, 120v) finned electric heater to heat this air. I figured a phase angle fired SCR power controller would do the job the best. (I really would like the best control I can get.) I have a temperature controller already with analog outputs, but now I'm looking around for an SCR power controller that could handle this heater. I'm worried because it's such a low power application, the heating element may only be drawing 1A, and the smallest SCR power controllers I can find are rated for 15A.

Would it be a bad idea to use an over-sized SCR power controller (rated for say 15A) on a heating element that will only be drawing around 1A? Are there negative effects (worse temperature control?) for using an over-sized SCR power controller for this application? Or is there somewhere I can get a phase angle SCR power controller that's rated better for this smaller application?

Thank you very much.

 

[MaxHeadRoom78]

No problem, if it is that small a load a off the shelf light dimmer should do it.
M.

 

[Finestein]

Can one buy a light dimmer that can be controlled by a 0-20mA or 0-10Vdc analog output signal from a proportional temperature controller?

 

[MaxHeadRoom78]

You may have to come up with a method of custom application.
Max.

 

[alec_t]

Googling "voltage-controlled light dimmer" gives many hits which may be useful, particularly if you want to go the DIY route.

 

[Finestein]

Okay Thank you. I am a beginner to electronics, so hopefully I will be able to find some prefabricated voltage-controlled light dimmer. But I suppose I can learn if there aren't any out there.

 

[MaxHeadRoom78]

In N.A. these are plentiful at most H.W. stores.
For more info on DIY control solutions see the Fairchild AN-3006.
Max.