Q: What is the
difference between Modified Squarewave (also called Modified Sinewave or Quasi
Sinewave) and True Sinewave?
A: The Modified Squarewave output is a
stepped approximation of the Sinewave.
The Sinewave output duplicates grid
Q: Do I need
Sinewave or Modified Squarewave?
A: More and more
modern appliances are now fitted with electronic control circuits that require a
pure sinewave to operate correctly. In domestic Solar Power Systems where a wide
range of appliances will be used we recommend to only use a sinewave Inverter.
Sinewave inverters should be used for the following appliances: TV, VCR,
computer, fax, printers, light dimmers, fans and any variable speed
Q: What size battery
bank should I use for a particular Inverter?
For a quick approximation take the continuous rating of the particular Inverter
and divide by the battery voltage, then multiply by ten.
eg: 600W 12V
Inverter requires 600 / 12 * 10 = 500 Amp Hours
Q: How does power
factor affect my Inverter?
A: All Inverter ratings
are specified at unity power factor, power factors other than one(1) place an
additional load on the Inverter, (note Watts = VA x power factor). For example a
300 Watt load with a unity power factor presents a load of 300VA on the
Inverter, where as a 300 Watt load with a 0.6 Power factor presents a load of
500VA on the Inverter.
Q: Can I fit an
inverter with a RCD to a vehicle?
inverters can be fitted with an earth leakage device or RCD, however in order
for these devices to operate the earth and neutral must be bonded at the input
of the RCD. In domestic wiring this scenario does not present any problems due
to the large earth plane that can be created. However, in vehicles the inverter
case which is connected to earth, would need to be connected with the vehicle
chassis to provide an earth plane. This connection results in earth, neutral and
battery negative being bonded together, which results in the loss of the
isolation between AC and DC.
Note: When using an RCD
an earth plane must be created for a fault path back to earth in order for the
device to trip.
Q: Why is DC /
AC isolation important?
A: If the DC and AC are
not isolated the Inverter would place dangerous AC voltages on the battery
terminals and greatly increase the potential for electric shock.
SnapTec inverters are completely isolated from input to output. Active and neutral are both floating with respect to the DC input and
Q: What is the
benefit of a toroidal transformer vs a switchmode
A: There are 2 styles of Inverter
technology. High frequency switchmode transformer and toroidal transformer
Each technology has advantages and disatvantages.The high
frequency switchmode Inverter is physically smaller and weights less, however it
is unable to supply large currents and therefore has a greatly reduced surge
capacity. The toroidal transformer, while larger and heavier, can supply large
currents and is far better suited for applications which require high surge
i.e. motors, fridges, power tools, microwaves, pumps, TV's