Hello all,
I am putting together a TRIAC power controller that will control a 4500-watt electric heater: ~18.75A@240VAC.
The TRIACs I am considering for this circuit are 40-amp TRIACS:
NTE56028 in TO-220: http://www.nteinc.com/specs/56000to56099/pdf/nte56028.pdf
NTE5679 in TO-3: http://www.nteinc.com/specs/5600to5699/pdf/nte5679.pdf
My concern is heat, and how to manage it effectively.
I am not familiar with how to calculate the heat generated by the TRIAC at a specific load.
I'm not even sure the load itself impacts the heat generated, to begin with, or if heat is generated strictly by the gate switching.
Maximum and average gate power of these TRIACS are:
NTE 56028: 20W Max / 0.5W Avg.
NTE 5679: 40W Max / 0.8W Avg.
I've tried searching online for explanations on the matter, but something is being lost in translation. I'm still not sure how to calculate how many watts of heat will be generated at the specified load.
Consider the NTE 56028. If the maximum gate power is 20W, and the max current rating is 40A, then I should think a ~19A load should produce ~10W heat. Please correct me if I am wrong!
Active cooling via fans is not ideal. For a variety of reasons, I'd like to use the TO-220 package, if managing heat inside an enclosure is an option. I'd like the project to be relatively dust and splash resistant as it'll be in my shop.
If heat build-up is going to be an issue, then a TO-3 TRIAC seems easier to mount on an external heat sink if need be.
My unguided (misguided?) direction at this point is this:
Thank you for any input!
Adam
I am putting together a TRIAC power controller that will control a 4500-watt electric heater: ~18.75A@240VAC.
The TRIACs I am considering for this circuit are 40-amp TRIACS:
NTE56028 in TO-220: http://www.nteinc.com/specs/56000to56099/pdf/nte56028.pdf
NTE5679 in TO-3: http://www.nteinc.com/specs/5600to5699/pdf/nte5679.pdf
My concern is heat, and how to manage it effectively.
I am not familiar with how to calculate the heat generated by the TRIAC at a specific load.
I'm not even sure the load itself impacts the heat generated, to begin with, or if heat is generated strictly by the gate switching.
Maximum and average gate power of these TRIACS are:
NTE 56028: 20W Max / 0.5W Avg.
NTE 5679: 40W Max / 0.8W Avg.
I've tried searching online for explanations on the matter, but something is being lost in translation. I'm still not sure how to calculate how many watts of heat will be generated at the specified load.
Consider the NTE 56028. If the maximum gate power is 20W, and the max current rating is 40A, then I should think a ~19A load should produce ~10W heat. Please correct me if I am wrong!
Active cooling via fans is not ideal. For a variety of reasons, I'd like to use the TO-220 package, if managing heat inside an enclosure is an option. I'd like the project to be relatively dust and splash resistant as it'll be in my shop.
If heat build-up is going to be an issue, then a TO-3 TRIAC seems easier to mount on an external heat sink if need be.
My unguided (misguided?) direction at this point is this:
- Use an aluminum project box. Ground the body of the project box.
- Mount the TO-220 NTE56028 against the wall of the project box (and electrically isolate it).
- On the other side of the aluminum wall, install a heat sink using a pad or thermal compound.
- Alternatively to using a heatsink, use a project box with built-in aluminum fins.
Thank you for any input!
Adam