Power Supply / Transformer help needed!

[ultimo101]

Hey guys, I want to thank you for help in advance.

We are working to design a household which utilizes an infrared heating source. The heater element is rated at 120v/1000w meaning I will need 120v coming from the wall to the heater. Now the electronic components of course need much less voltage meaning I would need a transformer. Now this is good, but of course limiting space is always key. This is why we would need an external transformer box, something like you would see on a laptop power cable.

Now what I am picturing is a power supply box with one cable coming IN from the wall, and TWO cables going to the unit. One of these cables will be the 120v line and the other would be the secondary voltage for the electronics.

I am not sure if this is practical for either a cost sense or design sense and this is where I need some input. I am not even sure if this is a common thing that we can purchase from wholesalers or it is something we should build ourselves.

Any pointers on what to search or overall design ideas would be greatly appreciated!

 

[RogerAF]

I would build the power supply in the unit, so only one cable goes to the wall outlet and everything else is inside the unit. You can purchase ready made switching power supplies that weigh next to nothing and provide any voltage @ current you need. This is a lighter weight alternative to transformer and linear power supply. If you use a transformer you will also need a rectifier, capacitor and probably a voltage regulator, maybe a heat sink. All of a sudden space and weight have grown. Of course if you only need a few milliamps you can use a small transformer and the other components don't need to be very big, but if you need more than an amp or two, a switching supply is the way to go.

Search Jameco , Mouser, McMaster-Carr, Thomas Net, etc. for the supply you need. Many come with DIN rails and screw terminals for input/output connections. Be sure to include fuses in your design, at least two: one for the heater and one for the electronics. They can save your house and life. When you are dealing with 1000W heat source it will get hot. Also it will be drawing at least 8.3A (1000/120) so make sure you use a large enough power cord 16awg or bigger.