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enter image description hereim just an electronic enthusiast #1? Is it posible to power the peltier with a motor speed controler 220vac input and varable output. If no, why? What are the remidies #2? And if i use a 48vdc power supply stack it in series What will b the power consumption. Thank u for any answer

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  • \$\begingroup\$ Would you be able to tell us what you're cooling? How to use a peltier depends greatly on application. \$\endgroup\$ – K H Apr 16 at 4:19
  • \$\begingroup\$ Im trying to make a small freezer w20in x L27in x H24in. I will use tec1-12715. How will i reduce the power consumption without sacrificing the performance of the peltier \$\endgroup\$ – Ralph Apr 16 at 16:00
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Is it possible to power the peltier with a motor speed controller 220vac input and variable output. If no, why?

Sure it's possible, is it safe? No.

Does the above circuit risk electrocution? If the motor controller does not have galvanic isolation, then yes.

The other problem is the output of the controller shows 220V, which is above the 48V rating of the peltier modules and is sure to exceed the maximum ratings and burn them up.

Find a DC power supply with voltage control at minimum. Also running peliters at full power can be bad because the heating from resistive losses in the peliters causes them to heat up and gives you less cooling

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  • \$\begingroup\$ The output of the controler can be adjusted to 0v to 220v dc so i will fixed it to 48v. And also use step down dc-dc converter with cc/cv output 48vdc. \$\endgroup\$ – Ralph Apr 16 at 16:09
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No, you shouldn' t do that. For the following reasons:

  1. The possible output voltage of 220 V is much higher than the maximum voltage the peltier elements are meant for (if the output ist controlled with phase cutting, than this applies even to dimmed output)
  2. Peltier elements should not be driven with alternating current as this will cause thermal stress, whitch is harmful to them
  3. You should implement a galvanic isolation to protect yourself.

So you will have to look for a PSU that is rated for 4×12V×6A = 288 W at 48 V.

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  • \$\begingroup\$ Also To transfer as much Q heat as possible use the lowest thermal resistance interface that fits with high velocity cooling (3m/s) on hot side to reduce the temperature drop on Peltier interface. \$\endgroup\$ – Sunnyskyguy EE75 Apr 15 at 18:49
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There is a long list of things which are not variacs! Motor speed controllers are on that list.

OP wants a variable voltage. What varies an AC voltage is a variac. they are heavy, bulky and expensive, which is why there is a long list of things which are not variacs. Those other things use tricks which are appropriate for the particular things they are driving -- lamp dimmers use leading or trailing edge triacs, fan speed controllers do what they do, motor controllers use VFD, etc. None of these things are designed to produce a sensibly varying voltage.

What OP really needs is a variable voltage DC power supply, and the best tech for that is electronic buck conversion down to a practical voltage for his project. Such power supplies which are UL listed (or to be more precise RU listed) are readily available at your friendly mail-order electronics supply house.

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