using AC devices with DC

[FC72CHF]

So what would happen if I connected a cartridge heater(basically just a resistance) designed for AC to a DC power supply? What about the reverse scenario, a DC device to an AC source?

 

[itsmoked]

Should be no difference. As long as you apply the same voltage. (RMS)

Keith Cress
kcress -

http://www.flaminsystems.com

 

[dpc]

For purely resistive elements, it shouldn't make much difference.

This would not be true for a relay coil or something with a significant inductance.

 

[alehman]

If there are any switches, thermostats or overtemperature safety devices, those may be designed for AC only.

 

[FC72CHF]

Well in this case I dont have any features like that, but if I did would I risk damaging them or would they just give erroneous results?

 

[alehman]

Some switching devices can only safely switch AC. DC can damage the contacts of those devices. You would need to check the ratings. If it's a simple resistor, the no problem.

 

[waross]

Even switching a resistor, some economy AC devices may not interrupt the current. This is manifested by an internal arc which quickly destroys the switching device. Use DC rated switches and switching devices for DC.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

What voltage and power is this this cartridge?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[FC72CHF]

Well the one I am specifically thinking about is 240V 2500W, I was also going to try this on some 120V 1800W heaters as well.

I was using a 240V variac, but would like to use a computer controlled DC psu that I already have(yes I know there are AC pc controlled psu, but funds are not infinite).

 

[itsmoked]

Well then you must be doubly careful with your switching and fusing as those voltages are in the realm of rarer devices that can handle it.

If your computer controlled psu allows you to ramp up and down, and is internally fault protected you are lucky and on your way I'd say.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[cranky108]

Not knowing what type of heater it is, Ill ask a dumb question. Does it have a fan motor?

The answer to your basic question is, yes some AC devices will work on DC, and some DC devices will work on AC. Having said that, it is important to eximine each component to see that it is compatable. (switches, relays, motors, coils, SCR's, and surge protection equipment). Even things as small as fuses can be sensitive to being DC operated.

 

[itsmoked]

Hi cranky.
Cartridge heaters are just that.. Cartridges - basically rods with wires coming out of an end.

http://www.watlow.com/products/heaters/ht_cart.cfm

Keith Cress
kcress -

http://www.flaminsystems.com