heating/ cooling plate: power resistors

Hi all,

Just after some advice really (or at least some reassurance) that my project idea will work. I’m building a heated aluminium plate using a 330 ohm, 50W power resistor (like these).

The power supply I will be using is a DC 24V, 10A, 240W max.

I will also be using an N-type MOSFET that is rated for 60V and 100A (It’s a TI CSD18534KCS) which will be heatsinked.

In addition to the heating elements I will also be using 4 peltiers in series (rated for 3.7A and 37.4W max), again controlled by the same MOSFET on the bed. (These will be in either on state or off state only).

I know peltiers can be used with say an H bridge to reverse the current to flip hot and cold sides, however for the application I have in mind, I reckon having separate hot/ cold elements is more suitable.

All of this will be controlled via Labview LINX, using the input of 5 thermistors.

Please find attached the circuit diagram of how I’ll wire everything up (I think my FET’s are correct but new to all this so apologies if I’ve got them connected wrong!)

If anyone has any suggestions I’m keen to hear. Also if anyone has any suggestions of any safeties I could implement (and where/ how to wire them up) I’d be grateful as I’m aware this could be a fire risk given the high current/ potential power!

What do the heater heat?. What do the coolers (peltier) cool?

Regards

Need to study a bit on processing photographs to a reasonable and sensible resolution for a Web page (less than 1000 pixels wide) - Irfanview will do this on WIndoze.

You need a pull-down resistor from gate to source of (each of) the FETs - 47k would do - to ensure they are switched off when not under control of the Arduino - such as on start-up.

Oops, sorry about the photo!

The heaters and coolers will be acting on an aluminium plate.

vffgaston:
What do the heater heat?. What do the coolers (peltier) cool?

Regards

Just to check, you mean solder a resistor linking the gate pins and source pins? or do do you mean I need a resistor before the wires into the gate or after the source pin on the FET?

Just after some advice really (or at least some reassurance) that my project idea will work. I'm building a heated aluminium plate using a 330 ohm, 50W power resistor (like these).

The power supply I will be using is a DC 24V, 10A, 240W max.

You may need to revise the value of R if you want to get any heat into the Al plate.

P = volts squared / R

=24 x 24 / 330

= 1.75W.

50W would appear to be an overkill.

Weedpharma

Is that a 10K resistor in series with the Pelletiers? Won't that limit the current to 2.4 mA? That's way below the 3.7A rating so I would not expect much cooling.

The heaters and coolers will be acting on an aluminium plate.

So the project is a “conceptual” one; I mean, you plan to heat/cool a plate just to experiment?

Regards