Durite 0-856-75 Power Inverter 1500W

What is the Difference between a Pure sine and Modified sine Power Inverter? Leave a comment

What is the Difference between a Pure sine and Modified sine Power Inverter?

Durite 0-856-75 Power Inverter 1500W


Both pure and modified sine wave inverters take 12V/24V DC from a battery and turn it into something that approximates the AC power normally available from the wall outlets in your home or business.

Both types of inverter will provide power to AC appliances, however Pure Sine is high quality equal to (or better than) the power in your home, Modified sine wave power is an simpler form of power and is adequate for simple electronics, but may damage more complex ones.

Choosing the right type

If you’re not 100% sure about which type of inverter would suit you best, ask yourself these questions:
    • Does my device or appliance use a motor?
    • Is my device a delicate piece of medical equipment?
    • Does my device or appliance use a rectifier?
    • Can my device be powered by a DC adapter?
If you answered yes to either of the first two questions, you may need a pure sine wave inverter. If you answered yes to either of the second questions, then you’ll likely be fine without one. 
When a Pure Sine Wave Inverter Isn’t Necessary

If you have the money, and you don’t mind spending more than you have to just for extra peace of mind and to future-proof your installation, then you can’t go wrong with a pure sine wave inverter. It will work just fine even in situations where you don’t really need one.

Pure Sine Wave A pure sine wave is what you get from your local utility company and from some pure sine generators.

  • major advantage of a pure sine wave inverter is that all of the equipment which is sold on the market is designed for a pure sine wave. This guarantees that the equipment will work to its full specifications.
  • Some appliances, such as motors and microwave ovens will only produce full output with pure sine wave power.
  • A few appliances, such as bread makers, light dimmers, and some battery chargers require a pure sine wave to work at all.
  • audio equipment, satellite systems, and video equipment, will run properly using pure sine wave inverters.
  • these are the most expensive of the inverter designs and outperform all other types of inverters, regardless of use.

Some devices and appliances that require a pure sine inverter are:

  • Microwaves
  • Laser printers
  • Variable speed tools
  • Cordless tool battery chargers
  • Some TV’s
  • Key Machines
  • CPAP machines with humidifiers
  • Medical equipment
  • Sensitive electronics


Modified Sine Wave A modified sine wave inverter actually has a waveform more like a square wave, but with an extra step. A modified sine wave inverter will work fine with most equipment, although the efficiency or power of the equipment will be reduced with some.

  • Motors, such as refrigerator motor, pumps, fans etc will use more power from the inverter due to lower efficiency. Most motors will use about 20% more power. This is because a fair percentage of a modified sine wave is higher frequencies – that is, not 60 Hz – so the motors cannot use it.
  • Some fluorescent lights will not operate quite as bright, and some may buzz or make annoying humming noises.
  • Appliances with electronic timers and/or digital clocks will often not operate correctly. Many appliances get their timing from the peak of the line power – basically, the modified sine has a flat top rather than a peak – this may cause the occasional double trigger. Because the modified sine wave is noisier and rougher than a pure sine wave, clocks and timers may run faster or not work at all.
  • Items such as bread makers and light dimmers may not work at all – in many cases appliances that use electronic temperature controls will not control. The most common is on such things as variable speed drills will only have two speeds – on and off.
  • most equipment will operate without any noticeable difference.

What Size Power Inverter Do I Need?

A power inverter is usually rated in Watts. A typical inverter will have two different wattage ratings- continuous and surge. The continuous wattage rating determines the amount of power it can deliver continuously for a long period of time while the surge rating specifies the amount of overload it can sustain for a shorter time span.

For example, an inverter rated 1750 W continuous and 5000 W surge can serve a load of 1750 W for several hours and sustain 5000 W surge during the short start-up period (which typically does not last longer than a few seconds). Inverters are also usually capable of sustaining overloads for short periods of time (the inverter cited in the example above can run 2000 W loads for about 15-20 minutes), but this should be used only in case of emergencies. Overloading inverters for longer periods will affect its longevity, cause excessive heating and damage equipment.

Please note that the power ratings listed below are indicative and actual power rating on the device may vary depending on the brand and type you are using.

Common Appliance Wattage Requirement
Laptop 100
Cellphone charger 15
Light (incandescent bulb) 100
Satellite TV 30
Printer 50
Radio 40
Radiator 2000
DVD player 28
Hair dryer 2200
Television 42″ HD 120
Games console 100-200
Washing machine 2200
Toaster 2000
Tumble dryer 2500
Dishwasher 2200
Iron 2800
Microwave 1000
Vacuum cleaner 2000
Radiator (oil filled) 3000

The first step towards deciding the size of inverter you need is determining your power needs. Identify the devices that you want to power from your inverter and add up the wattage requirements of individual appliances. It is advisable to buy an inverter which can handle additional 10-20% load than you actually need.

For example, if you need to run 1000W load by your inverter, it is advisable to buy an inverter which has a continuous wattage rating of at least 1200 W. This will ensure that the inverter is not unduly overloaded or heated up and lasts for a long time.

It is important to remember that inverters are not generators. They do not produce energy by themselves and need a reliable battery system to power your appliances. How long the appliances run depends on the capacity of the batteries that are providing juice to the inverter. In order to keep your appliances running for an appreciable amount of time, a reliable battery backup is of utmost importance.

The batteries need to be charged at regular intervals. If you are hooking your inverter to the batteries on your car or truck, you need to keep your vehicle running for the period that your inverter needs to be working.

View more of >>> 12V Power Inverters 

View more of >>> 24V Power Inverters

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