POWER INVERTERS
Q: What is an inverter?
A device which changes direct current (DC) into alternating
current (AC).
Q: What size of inverter should I use?
The size you choose will depend on the watts of the appliance or
tool you want to run (find the power consumption by referring to
the specification plate on the appliance or tool). We recommend
you to buy a larger model than you think you'll need (at least
10% to 20% more than your largest load).
Example: You want to power a computer with 17" monitor and a
lamp.
Computer and monitor: 300 Watts
75 Watt lights: 75 Watts
Total Needed: 375 Watts
For
this application, you would need a 400 Watt inverter. You should
consider a larger unit than your minimum requirements, as there
will likely be a time when you wish you would have bought a
higher capacity model.
If
the wattage of the appliance or tool is not listed explicitly on
the specification, you may use the following formula.
Multiply: AMPS X 120 (AC voltage) = WATTS.
Example: On the microwave shows 10 AMPS for continuous use.
The Wattage is 10 AMPS x 120 V = 1200 Watt
Q: Why can't the 1500 Watt inverter run my 1200
Watt microwave?
The power commonly advertised for microwave ovens are the
cooking power (the power delivered to the food) not the power
actually consumed by microwave oven. The microwave ovens might
consume 40% to 100% more than its advertised cooking power.
The recommended inverter to run 1200 Watt microwave is 2500 Watt
or larger.
Q: What is meant by the terms "continuous
wattage" and "peak surge wattage" on the inverters?
The "continuous wattage" is the wattage that the inverter can
supply 24/7 as long as the DC input power supply is in good
condition (usually, the DC power supply is a car battery)
The "peak surge wattage" is the maximum wattage that the
inverter can supply for very short period of time (a split of a
second)
NOTE: Induction motors such as air conditioners, refrigerators,
freezers, microwave ovens, and pumps may have a start up surge
of 3 to 7 times the continuous rating. Heat generating
appliances such as hair dryers and water heaters will have high
peak surges as well.
Example:
If
the microwave oven has peak surge which is 4 times the
continuous wattage, the 1200 Watt continuous microwave ovens
will have 4 x 1200 Watts = 4800 Watts peak surge.
The
recommended inverter to run 1200 Watt continuous and 4800 Watt
peak surge microwave is 2500/5000 Watt inverter or larger.
In
general, induction motors require an initial surge of power to
start up ("starting load" or "peak load"). Once started, the
tool or appliance requires less power to continue to operate
("continuous load")
Q: Are there any disadvantages of using "Square Modified Sine
Wave" inverter?
"Square Modified Sine Wave" inverters will run most tools and
appliances without any problem and are the most common type of
inverter on the market.
Below are the advantages of "Pure Sine Wave" (also called True
Sine Wave) inverters over modified sine wave inverters:
1. Reduces audible and electrical noise in fans, audio
amplifiers, TV and some sensitive audio system.
2. Inductive loads like microwave ovens and motors might run
faster, quieter and cooler.
3. The following devices that might not work with modified sine
wave inverters:
· Some battery chargers for cordless tools
· Some new furnaces and pellet stoves with microprocessor
control
· Sensitive electrical or electronic items such as certain
medical equipment
