Capacitor Voltage Divider

[Chemelec]

At 50 or 60 HZ, you would need VERY BIG Capacitors to Pass 5 Amps and they would need to be Rated at Considerably Higher than the Line Voltage. They should also be NON-POLARIZED.

I Do Not know Specifically Which ones you have?, But I Think you will find that If you supply 12 Volts to your Peltiers, they will probably draw about the 5 Amps.

Most of the ones I have, Have a Nominal Rating of 14,4 volts, Mainly because in a Vehicle where they are often used, that is what the Voltage is when the Car is Running.
I have Peltiers with as low as 3 Amp and up to 15 amp Ratings.

 

[fatman57]

At 50 or 60 HZ, you would need VERY BIG Capacitors to Pass 5 Amps and they would need to be Rated at Considerably Higher than the Line Voltage.

Well that scraps that plan.

Most of the ones I have, Have a Nominal Rating of 14,4 volts, Mainly because in a Vehicle where they are often used

How are they usually used in this application?

Mine are 60W from a known online bidding site, I got them a while ago but 14,4v sounds about the same I think. I presume there is no problem running them at lower voltages, just that some efficiency might be lost?

 

[Chemelec]

Usually these Peltier devices are Typically used for Small Coolers in cars or campers.

Some Special ones are used for Cooling Slides on Microscopes.
So to keep Frozen sections Frozen while viewing them..

 

[fatman57]

Usually these Peltier devices are Typically used for Small Coolers in cars or campers.

Thanks, I wondered if they had an application in the car as manufactured.

In scientific applications they are much more useful apparently, able to respond quickly to demands. Faster pulsing (to create changes in heat) is supposed to lessen their service life due to heat cycling.

Do you have any links with further info on Peltiers and why/how they have optimum current/voltage etc?

 

[Alec_t]

capacitors will be able to cope with these high currents in this application, no?

To pass 6A at 50/60Hz would require a low ESR (equivalent series resistance) capacitor of at least 85uF with a working voltage of at least 350V AC (for a 240V supply). That wouldn't be cheap or easy to source.

 

[Chemelec]

Thanks, I wondered if they had an application in the car as manufactured.

In scientific applications they are much more useful apparently, able to respond quickly to demands. Faster pulsing (to create changes in heat) is supposed to lessen their service life due to heat cycling.

Do you have any links with further info on Peltiers and why/how they have optimum current/voltage etc?

They do not have applications in the car as manufactured.
Forgot to mention, They also have applications in some Computers to help in keeping the Microprocessor Cool.

I have numerous Catalogues with Data, but they are physical books, so not easily posted here.

I have not had any problems with High Frequency Pulsing as in supplying power using PWM, But Steady DC Current gives better Efficiency.

MOST important is in Keeping the Hot Side COOL.