Square sine wave or natural sine wave?

[The_Unbeliever]

Which is the best for appliances like fridges? A square sine wave, or a natural sine wave?

Which appliances can be run safely on square sine waves, and which appliances MUST have natural sine wave?

TIA

Ook

 

[Sinbad]

Anything with a motor should have pure sine.

 

[Beachless]

Most definitely pure sine.

 

[The_Unbeliever]

So it is safe to have square sine wave for lights, and pure sine for motors.

Thanks. Just a question I've had.

 

[Bar0n]

Which is the best for appliances like fridges? A square sine wave, or a natural sine wave?

Just an FYI: Square [-]sin[/-] waves are inherently non-sinusoidal.

 

[Sinbad]

Just an FYI: Square [-]sin[/-] waves are inherently non-sinusoidal.

Modified sine

 

[Beachless]

So it is safe to have square sine wave for lights, and pure sine for motors.

Thanks. Just a question I've had.

It depends on the type of light. CFL's dont like square wave inverters but may be OK with a good quality modified sine wave inverter.
Modified sine inverters may have 3, 5, 7 etc steps in the wave so its important to know before you buy.

A fancy one will look like this:



And a cheapie like so:

 

[balky]

Note that fridges have a huge inrush current when the motor starts, so you would need an inverter with a much higher rating than the actual motor rating otherwise the inverter will probably trip when the motor starts.

 

[sovielenamen]

Note that fridges have a huge inrush current when the motor starts, so you would need an inverter with a much higher rating than the actual motor rating otherwise the inverter will probably trip when the motor starts.

A simple startup current limiter as in microwave ovens should fix this problem for cheap.
Makes more sense then a oversized inverter.

 

[balky]

A simple startup current limiter as in microwave ovens should fix this problem for cheap.
Makes more sense then a oversized inverter.

A single phase induction motor is non self-starting. In order to get around this, they use a capacitor to start the motor, which results in a current surge and this energy surge overcomes the inertia of the rotor. I speak under correction, but I think if you limit the inrush current, then the motor may not start.

 

[BigEars]

Anything SMPS is generally fine with simulated Sine Wave. Gets converted into DC anyway for the Chopper Stage.

As far as anything with windings...think a fridge, deep freeze, a house fan, a microwave, your nice Hi Fi amp with a linear transformer, your little bedside radio that runs off mains...will get damaged if run off a simulated Sine Wave inverter. Some last a while and some die quickly. Still a bad idea. Simulated Sine Wave is less efficient than Pure Sine Wave for things with windings because they cause the windings to heat up. More heat = less life.

 

[rsifan]

It depends on the type of light. CFL's dont like square wave inverters but may be OK with a good quality modified sine wave inverter.

what type of issues will you experience with CFL bulbs?

I went on a bulk buying spree about a year ago and have 10 spare CFL bulbs, and was thinking of using 4 of those (2 x 11w each and 2 x 15w each) with my modified sine wave inverter.