The AC output waveform of the 2500W INVERTER
is called a "quasi-sine wave" or a "modified sine
wave". (See Figure 2). It is a stepped waveform that is designed
to have characteristics similar to the sine wave shape of utility
power. A waveform of this type is suitable for most AC loads, including
linear and switching power supplies used in electronic equipment,
transformers, and motors. This waveform is much superior to the
square wave produced by many other dc to ac inverters.
Figure 2. Modified Sine Wave
CAUTION: RECHARGEABLE APPLIANCES
Certain rechargers for small nickel cadmium batteries can be damaged
if connected to the 2500W INVERTER.
Two particular types of equipment are prone to this problem:
1) Small battery operated appliances such as flashlights, razors,
and night lights that can be plugged directly into an ac receptacle
2) Certain battery chargers for battery packs used in hand power
tools. These chargers will have a warning label stating that dangerous
voltages are present at the battery terminals.
DO NOT USE 2500W INVERTER WITH THE ABOVE EQUIPMENT.
This problem does not occur with the vast majority of battery operated
equipment. Most of this equipment uses a separate charger or transformer
that is plugged into the ac receptacle and produces a low voltage
output. If the label on the ac adapter or charger states that adapter
or charger produces a low voltage ac or dc output (less than 30
volts), 2500W will have no trouble powering this charger or adapter
The modified sine wave produced by the 2500W INVERTER is designed
to have an RMS (root mean square) voltage of 115 (or 225) volts,
the same as standard household power. Most AC voltmeters (both digital
and analogue), are sensitive to the average value of the waveform
rather than the RMS value. They are calibrated for RMS voltage under
the assumption that the waveform measured will be a pure sine wave.
These meters will not read the RMS voltage of a modified sine wave
correctly. They will read about 2 to 20 volts low when measuring
the output of the 2500W INVERTER. For accurate measurement of the
output voltage of the 2500W INVERTER, a true RMS reading voltmeter,
such as a Fluke 87, Fluke 8060A, Beckman 4410, or Triplett 4200,
must be used.