Is A Transformer?
In its most basic form, a
transformer is a laminated steel core wrapped with insulated copper
wire with at least two coils or windings. A transformer, again in its
most primitive state, has no moving parts and is normally a
trouble-free device. Transformers are designed to step up (increase)
or step down (decrease) AC voltages through the principle of mutual
inductance which causes a voltage to be induced from one coil into
another coil because of the relative motion of the collapsing and
expanding magnetic field resulting from the constantly alternating
current (60 times per second). The primary coil is the input coil or
power source and the secondary coil is the output coil or load.
The core is not a solid
component but rather is many layers of thin steel called laminations.
This core is the "link" that magnetically "connects"
the primary winding to the secondary winding. When AC power is
applied to the Primary coil a magnetic field is produced within the
core, also known as Flux, that induces voltage in the Secondary coil
The ratio of the number
of wire turns in the primary windings versus the secondary windings
determines whether a transformer is a step up or step down. For
example, 120 turns on the primary versus 30 turns on the secondary is
a 4:1 ratio and if the input voltage was 480 volts the secondary or
output would be 120 volts. This would, obviously, be a step down
The type of transformer
we have been describing so far is an isolation transformer. That is,
the windings or coils are physically separated from each other.
Another, very common, type of transformer is the autotransformer
which consists of a single "tapped" coil in which the turns
between the tap and one end of the primary winding comprise one coil
of the transformer and the entire primary winding comprises the other
coil. An autotransformer in the lower winding ratios is very
lightweight, physically smaller, and therefore more economical than
its isolation transformer counterpart. The transformers we sell here
and elsewhere for international voltage converter purposes are all
Wattage refers to the amount of power
(electricity) consumed by your appliances and equipment. Sounds simple,
doesn't it? Actually it is very simple and it is important to know a
little about it because you need to know wattage in order to choose a
Converter or a Transformer. The wattage of most appliances and
equipment is found on decals or labels of some sort on the appliance or
equipment or in the owner's manual. In addition, the decals or labels
also usually give the voltage and/or amperage of the appliance.
the wattage isn't given you can still figure it out if you know the
voltage and amperage. If you multiply the voltage times the amperage,
the result equals the wattage of the appliance. For example, the decal
on the appliance you want to take overseas doesn't list the wattage but
gives the voltage as 120 volts and the amperage is 1.1. To find the
wattage of that particular appliance, multiply the voltage 120 times
the amperage 1.1, 120X1.1=132 watts.
manufacturers of transformers recommend that the
connected wattage not exceed 90% of the Transformer's rated wattage.
For example, don't connect more than 450 watts to a 500 watt
you know how to figure the wattage (either look on the label or do the
simple math) you are ready to select a converter and/or a transformer.
To choose either one you first decide which appliances you want to use,
second get the wattage of each item, and third, decide how many
appliances you will use at one time. See which of the three situations
below applies to you, then look at the solutions and examples:
3). You will bring and use more than one appliance.
SOLUTION 1). Just find the
wattage of that one appliance and choose the converter or transformer
that suits your needs.
SOLUTION 2).If you know for a
fact that you will never use more than one appliance or piece of
equipment or combination thereof at one time then you find the highest
wattage of your appliances and choose the converter or transformer that
has a higher wattage than that one appliance.
SOLUTION 3). Add all of the
appliance wattage you will use at one time and once again choose the
Converter or Transformer with a wattage rating higher than the total of
all the appliances you intend to use at one time:
EXAMPLE 1. If your ungrounded
appliance has a wattage of 550 watts you can choose between the
ungrounded step down Hi-Lo converter (use it with the wattage switch
set before plugging into the wall at the 25-1875 watts setting) or the
VC-1000 step up / step down transformer. If your appliance is grounded
or you want to use it for long periods of time, you will have to choose
one of the Transformer model because the converters aren't grounded and
can't be used for longer than 45 minutes to one hour. The advantages of
converters are: inexpensive, lightweight, and compact.
EXAMPLE 2.In this example you
could choose the ungrounded Hi-Lo converter that has two settings 0-25
watts and 25-1875 watts. WARNING! Always switch to correct wattage
range before plugging into an adapter that should already be in the
wall outlet, if an adapter is used. You could also choose the step up /
step down transformer VC-2000. The Hi-Lo converter is not intended for
continuous use and must be unplugged from adapter which also must be
removed from wall outlet as soon as you are finished with appliance or
equipment. The advantages of converters are they are: inexpensive,
lightweight, and compact.
EXAMPLE 3A. You are bringing 3
ungrounded appliances that you have to use at the same time with the
following watts: 1400, 350, and 150. The total of all the watts is 1900
watts which is too high for any of the converters but you could choose
the step up / step down transformer model VC-3000 . Remember you don't
want to load the transformer more than approximately 90% of its rated
EXAMPLE 3B. You want to bring a
300 watt grounded appliance, a 500 watt ungrounded, and a 800 watt
grounded appliance and you have to use them all at the same time for
long periods of time. You would add all of the watts, 1600 watts total,
and choose the VC-2000 model transformer. You couldn't choose a
straight converter, even though it has a wattage rating above the 1875
watts of all these appliances for two very important reasons, 1). you have some grounded appliances and 2). you intend to use them for long periods of
time. Either of the previous reasons preclude the use of a Converter,
they can't be used for long periods of time and they aren't grounded.