Exceptions

Are there any devices which absolutely, positively will not run on DC?

Helena.

Yes, Induction motors (ones without brushes) as used in fans, compressors, refrigerators, washing machines, the motor part of (hair and cloths) dryers and some power tools will work only on AC. If you see brush caps on the motor (or can look into it to see the carbon brushes) as in sewing machines, some power hand tools these will usually work on DC or AC. Battery operated drills, saws, and other tools will work on DC. Filament light bulbs, electric water heaters, toasters. toaster ovens, coffee pots, heater element in dryers of all types will work on DC or AC. Electric space heaters with fans will only work on AC, those that only radiate heat with no fan will will work on DC. LED's primarily work on DC but will work on AC if a power supply is used. Anything that has a transformer in it must take AC unless it has a connection that bypasses the internal power supply and is labeled with a given DC. This includes florescent lights, sodium vapor lights, mercury vapor lights, TVs, Microwave ovens, desktop PCs, and some radios. Some items like radios and ham equipment are set up to be able to take AC or DC. One needs check on the back of the unit to see what it will take. Sometimes the name plate on the tool or device will say it will work on AC or DC. Follow the proper voltages that are needed in all cases.

The quality of AC needs to also be discussed. Some things that have transformers in them like florescent lights will not work properly if the frequency gets over 100 Hz or drops too low below 50 Hz. Some inverters produce modified sine wave (closer to a square wave). This introduces a lot of harmonics and will not work very well for communications type equipment and heavy load starting capacitor start induction run motors (refrigerator, washing machines) tend to have problems starting.

Offered by Mike.