A Question About Adding an Inverter...

[Thehobe1]

Originally Posted by Tfryman

Actually, it's motors that don't like the MSW inverters. Most electronics just take the AC and rectify it to DC anyway so the MSW makes no difference UNLESS it is cheap electronics with little or no filtering of the rectified DC output. With poor or no filters the high frequency harmonics get through and mess with the DC circuitry.

I agree with your comment on motors which will run hotter with the Modifed Sine Wave (MSW) power source but I disagree with the comment on electronics.

I have spent 15-20 years designing IC's used in switching regulator applications such as computers, radio, TV and other industrial electronics. I am somewhat familiar with many, as you say "and rectify it to DC anyway" applications and the circuits used in them. The typical "cheap" AC to DC designs use circuits that WILL be more trouble with MSW. First, the input rectifiers and capacitors will have to deal with more ripple current that is hard on the input capacitors (ESR). Secondly, the DC to AC within the general electronic items will have to deal with a fair amount of input ripple current (at ~60 Hz), resulting in potentially higher frequency harmonics that you describe. The MSW could potentially damage the electronic items (some manufacturers actually specify NOT to use MSW power for their units and that it will void any warranty) and certainly will reduce the lifetime of general electronic items.

[The Gritz Carlton]

You took the words right of my mouth!!

[honda90]

Originally Posted by Thehobe1

Just for your info. I put in a 1200W sine wave inverter from AIMS that includes a transfer switch (which you will need) for around $169.

The TVs will take around 60 Watts each and they may be happier with a pure sinewave but probably fine with the approximate sine ones (referred to as "modified sinewave) because of the TV's internal switching power supply will act accordingly. The modified sinewave will be a little harder on the TV's internal capacitors but they have a 10-15 year life.

The microwave in my unit (Veagas 25.2) takes right around 800 Watts and the covection oven takes just over 1000 Watts.

I think 1200-1800 Watts is about the ideal range but you still have to be careful about all of the loads you would be running at the same time.

Amazon has the Aims 1200 W true sinewave and it is a very good deal. You should also buy the remote switch running the wiring through cabinets to a convenient wall control location.

If the inverter malfunctions, like many of the issues post here about losing power, you will also lose the generator/shorepower for these appliances because the transfer switch needs to be operating (12V DC input) for the transfer switch to connect the external AC power in when the inverter is turned off. (so it's not really completely off).

could you post a few pics of what your set up with your inverter looks like. I'm thinking of putting in one but it doesn't seem like an easy thing to do. tks