Modified sine wave

[Hutch]

Friends, what applications are NOT, repeat NOT, appropriately powered by a modified sine wave inverter?  In other words, what would suffer?

[zahc]

Basically if it uses a switch-mode power supply, or if it is a resistive load, it will be fine. Most motors will work OK as well.

Modified sine waves contain a high amount of higher harmonic frequencies. For example besides just 60Hz and 120Hz etc. like normal sine waves, they have information/energy at higher frequencies like kHz and up. If the device has a power supply designed solely to rectify and filter clean 60Hz, these higher harmonics will get through.

The thing is most modern equipment does not use traditional power supplies; most stuff nowadays uses switch-mode power supplies which by design operate in the kHz range, so a modifed sine wave doesn't bother them--they are already designed to filter those frequencies out. Computers, modern "universal"/lightweight wall-warts/phone chargers, etc don't care. Neither do resistive loads and simple motor loads like hair dryers, space heaters, incandescent lights, reciprocating saws, etc. but things like traditional linear/audio amps are not going to perform well at all or possibly be damaged.

[Hutch]

Okay, don't run traditional audio amps.  Doesn't rule out much.  Any more to be DQ'd?

[zxcvbob]

Okay, don't run traditional audio amps.  Doesn't rule out much.  Any more to be DQ'd?

You should be able to smooth the waveform and eliminate much of the harmonics by using an isolation transformer between the inverter and the load.

[Hutch]

You should be able to smooth the waveform and eliminate much of the harmonics by using an isolation transformer between the inverter and the load

Way above my paygrade.  I need some simple guidelines to allow me to decide whether to by a pure sine wave inverter (Spendy) or MSW model (less spendy).  If the only gotchas for MSW are stereo gear, then that's not much to give up in an emergency.

[RoadKingLarry]

Just add this to the circuit

[zxcvbob]

Go with the MSW inverter, and if you have to plug sensitive audio equipment into it, filter it (a transformer is the simplest) and/or make sure there's at least some resistive load plugged in too (an old fashioned lightbulb or two)

You'll also find that some inverters do not like having nothing but a motor or fluorescent lights for a load -- you can make them happy by adding a 100W lightbulb along with whatever.  I have to do that to run my tablesaw off my inverter-generator, otherwise the inverter trips before the motor is up to speed.  It handles the saw just fine once the motor is started (I wonder how it would do if I put a clutch on the motor pulley?)

[RevDisk]

Anyone else notice the "two enter, one leave" wiring schematic for the arena? 

 

[Doggy Daddy]

Anyone else notice the "two enter, one leave" wiring schematic for the arena? 

 

cute. 

DD

[Triphammer]

 I've heard that chargers for cordless drill & such won't work/ are damaged running on an MSW inverter. Would the light bulb work for that? The isolation transformer?

[TommyGunn]

Anyone else notice the "two enter, one leave" wiring schematic for the arena? 

 

cute.  

DD

It's a transistor!!!!!!!

[kgbsquirrel]

What aisle are the flux capacitors kept in again?

[MillCreek]

Hey, I have made Magic Smoke appear on a few circuit boards.  So that is where it is kept.

[never_retreat]

I had an ell crapo mod sign wave inverter and If I remember correctly my dewalt chargers would not work.
Can't remember and I smoked that thing awhile ago.

[RoadKingLarry]

What aisle are the flux capacitors kept in again?

Right next to the dilithium crystals and across the aisle from the proton accelerator packs.

[geronimotwo]

It's a transistor!!!!!!!

no, thunderdome!