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<title>Transformers and Inductors from Hill Technical Sales</title>
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<table><tr><td><font FACE="ARIAL">
<font FACE="ARIAL"><h2>Transformers and Inductors</h2></font>
Hill Technical Sales offers a large range of standard and
custom designs from the best manufacturers in the world. Most
custom designs can be processed in 1 to 2 weeks. Pricing on standard
products can normally be quoted the following business day.<p>
<h4>Types of Transformers available</h4>
</font></td>
<td><img SRC="graph/trans1a3.jpg" WIDTH="328" HEIGHT="258"></td><tr></table>
<p>
</font>
<center>
<table><tr><td><font FACE="ARIAL">
<ul>
<li>Auto Transformers
<li>Control Transformers
<li>Controlled Ferroresonant
<li>Controlled Ferroresonant Ballast
<li>Current Transformers
<li>Custom Coils
<li>Edge Wound Transformers
<li>Ferrite Core Transformers
<li>Ferroresonant Transformers
<li>Ferroresonant DC to AC
<li>Filament Transformers
<li>Foil Wound Transformers
</ul></font></td><td><img SRC="graph/sp30.gif" WIDTH="30" HEIGHT="1"></td>
<td><ul><font FACE="ARIAL">
<li>Inductors (AC Line/Load, DC Link, DC Filter)
<li>Medical Transformers
<li>Mercury Vapor Ballast
<li>Potential Transformers
<li>Power Transformers
<li>Saturable Reactors
<li>Step-Up \ Step-Down Transformers
<li>Toroidal (10 VA To 10,000 VA)
<li>Vibratory Feeder Coils
</ul></font></td></tr></table></center>
<p>
<hr>
<h3>PARTS OF A TRANSFORMER</h3>
<font FACE="ARIAL">
There are three basic parts of a transformer:
<p>
<ol>
<font FACE="ARIAL" COLOR="#800000">
<li>an iron core which serves as a magnetic conductor,
<li>a primary winding or coil of wire and
<li>a secondary winding or coil of wire. </font>
</ol>
<p>
The primary is usually referred
to as the input; the secondary as the output.
</font>
<p>
<h3>PRINCIPLE OF OPERATION</h3>
<font FACE="ARIAL">
An alternating current applied to the primary winding induces a alternating
magnetic flux in the iron core. Most of this flux stays with in the core
and only a small percentage of it travels through the air. The alternating
magnetic flux in the iron core then links the turns of the secondary
windings inducing a voltage. This all follows from Faraday's law of
induction. This explains why the primary has a voltage, and the secondary
has a voltage, yet there is no interconnection between them.
</font>
<h3>WHY WE USE TRANSFORMERS</h3>
<p>
<h4>TO DISTRIBUTE POWER AT HIGH VOLTAGE.</h4>
<p>
<font FACE="ARIAL">
It is more cost effective to distribute power at higher voltages since
power dissipation (loss) in a resistive load is given by the square of the
current times the resistance of the wire. It is best to use the lowest
possible current and thus the largest potential difference (voltage). A
typical transformer will take in input of 480 or 600 volts and step the
voltage down to 240 volts for some motors, or 120 volts for other
applications like consumer products, lights, etc.. The overall result is
better voltage regulation, minimized line loss and reduced wiring costs.
<p>
<h4>TO ELIMINATE DOUBLE WIRING.</h4>
<p>
<font FACE="ARIAL">
For maximum safety, 120 volt lighting and control circuits may be obtained
from 240, 480, or 600 volt power circuits by installing transformers at
the most convenient location to the load. This eliminates separate
circuits and independent metering for power and often results in
substantial savings.</font>
<p>
<h4>TO INSULATE CIRCUITS.</h4>
<p>
Installing transformers provides a means of subdividing circuits to
accommodate independent demand. Connecting to a 3 phase, 480 volt circuit a
transformer can provide
<ol>
<li>120/240 volt 3 wire single phase load:
<li>120 volt single phase load:
<li>240 volt single phase load.
</ol>
Transformers permit grounding of each low voltage circuit.
<p>
<h3>TYPES OF TRANSFORMERS</h3>
<p>
<h4>AUTO TRANSFORMER</h4>
<p>
Auto-transformers are used strictly in a step-up or step-down application. They are very similar to isolation transformers with one important exception. In an auto-transformer the primary and secondary windings are electrically common to each other. The advantage of using an auto-transformer over an isolation transformer is its smaller size and lower cost. The major disadvantage is no isolation between the primary and secondary which allows noise on the power line to be directly coupled to the load. One last disadvantage is that auto-transformers provide no regulation. It is also important to note that the greater the change in voltage the less cost effective a auto-transformer is. Some common applications for auto transformers are motors, heaters, and other non sensitive loads.
<p>
<h4>CONTROL TRANSFORMER</h4>
<p>
Used primarily in a step-down environment to power low voltage accessories.
Sizes: 5VA minimum rating.
<p>
<h4>CONROLLED FERRORESONANT (also see ferro's)</h4>
<p>
Special type of ferroresonant transformer that has an additional winding
which a variable DC control voltage is applied. When this winding is used in conjunction with a feed back circuit the transformer provides much tighter secondary regulation. This can also be used to add flexibility to the output voltage based on the designers requirements, for example regulation adjustment for different frequencies. .
<p>
<h4>CONTROLLED FERRORESONANT BALLAST</h4>
<p>
This ballast offers a linear variation of output power from 40 to 100% as
opposed to capacitor switching which changes lamp power as a step
function. This is accomplished by varying the conduction time on an
inductor which negates capacitance in the circuit allowing enhanced
control of lamp current. Lamp current is sensed in a closed feedback
loop circuit which can instantaneously respond to changes making the
necessary adjustments. A PLC interface is available to communicate with
the ballast in order to vary lamp output. In order to protect all of
the control circuitry from power problems typically found on the primary
the control circuits are all located on the secondary of the ballast.
<h4>Features:</h4>
<ul>
<li>Continuously variable output power from 40% power through 100% power
<li>Precise regulation. Less than a 2% change in output power over an input range of +l0% to -20%.
<li>No need for mercury relays.
<li>Very high input power factor. Typically better than 0.90
<li>High watt efficiency
<li>Controllable via a Programmable Logic Controller (PLC). A 4-2Oma signal is preferred with 0-5v and 0-lOv optional
<li>All components are pre-wired and tested at the factory
<li>Easy to wire. Just six wire connections need to be made to make the system operational
<li>Capable of running either a standard mercury lamp or metal halide lamps
<li>Secondary wave-forms are designed to improve lamp life
</ul>
<p>
<h4>CURRENT TRANSFORMERS</h4>
<p>
Current transformers are designed for connection in series with the line in
the same manner as that for ordinary ammeters- the secondary current bears
a known relation with the primary current; consequently, any change in the
primary current will be reflected in the meters or other devices connected
in series with the secondary terminals of the transformer. Sizes vary from
ID of 0.60" to 8" and up to 10" x 24" for bus bar designs.
<p>
<h4>CUSTOM COILS</h4>
<p>
We can supply coils of most any size to be used with or in various OEM
assemblies.
<p>
<h4>EDGE WOUND TRANSFORMERS AND COILS</h4>
<p>
<table><tr><td><font FACE="ARIAL">
Edge winding is a technique in which a rectangular magnet wire is wound on
its narrow edge. This allows a much greater surface area to dissipate more
heat than conventional winding techniques. Edge winding is used mainly in
isolation transformers and inductors that have high load currents at lower
voltages.</font></td><td><img SRC="graph/inductx.jpg" WIDTH="370" HEIGHT="307"></td></tr></table>
<p>
<h4>FERRITE CORE TRANSFORMERS</h4>
<p>
Ferrite materials are used for high frequency magnetic applications which
include transformers and inductors Ferrite materials are used because of
their efficiency and responsiveness at these frequencies, enabling the
power supply designer to reduce the size of magnetic designs dramatically.
Cores come in over a dozen shapes and a multitude of sizes. The components
in a power supply and the ferrite core transformer are closely intermingled
electrically by design, and each has a great effect in the performance of
the other. In this case it is important to fill out the general
specification sheet and then for our engineers to work closely with you on
these designs.
<p>
<h4>FERRORESONANT SQUARE-WAVE TRANSFORMER</h4>
<p>
Used primarily in uninterruptible power supplies . The transformer is used
to take a low voltage "pulsed square wave" generated by an inverter and
battery and convert it to an AC sine wave where voltage is regulated
1 to 5% depending on your requirement.
Sizes: The typical size range for this product would be 100VA through 25KVA
50Hz or 60Hz. However, we can produce inverter transformers with any VA
rating
<p>
<h4>FERRORESONANT TRANSFORMER FOR DC OUTPUT</h4>
<p>
Used primarily in brute force DC power supplies. The ferroresonant
transformer takes a sine wave input and creates a regulated square wave
output which is ideally suited for rectification. The square wave will
produce a lower ripple than a sign wave using the same filter capacitor.
Sizes: 25 watts to 10 kilowatts 50Hz, 60Hz, or 50/60Hz.
<p>
<h4>FERRORESONANT TRANSFORMER SINE WAVE</h4>
<p>
This takes a sine wave input and produces a sine wave output with a choice
of output voltage variations of 1, 3, or 5 % for an input voltage
variation of +10/-20%. These are used in an integrated power protection
systems, protecting the critical load from all power problems with the
exception of a blackout. Multiple voltages are available so this
transformer can replace a multi-tap input transformer.
Sizes: This product is available in sizes from 30VA through 75KVA single
phase or three phase 50hz or 60hz.
<p>
<h4>FILAMENT TRANSFORMER</h4>
<p>
Similar to control transformers except they provide power to x-ray tube
filament. Typically, one requirement is very high dielectric strength from
the secondary to ground and from the primary to secondary.
Sizes: over 50VA minimum rating.
<p>
<h4>FOIL WOUND TRANSFORMERS</h4> <p>
These are used in high current applications. The coil is wound with either
copper foil or aluminum foil. Used when low voltage high current is
required.
<p>
<p>
<table><tr><td>
<img SRC="graph/induc.jpg" WIDTH="295" HEIGHT="276"></td><td><font FACE="ARIAL"><h4>INDUCTORS</h4>
Also known as chokes, DC link, AC line/load reactors, and buck/boost
inductors. Inductors are found in most electrical power conversion
applications. Smoothing chokes are used to filter the AC ripple in a
low-frequency DC power supply. Inductors are used to filter out RFI
(Radio Frequency Interference). In another application they are used as
current-limiting reactors for overload and short-circuit protection or to
limit high inrush currents that might occur on the start up of an electric
motor. </font></td></tr></table>
<p>
Wide-band inductors are used at a multitude of frequency levels to
filter out unwanted frequency noise leaving a clean fundamental signal.
Inductors come in virtually all windings and constructions forms, dictated
by the frequency and current they are to handle.
<p>
DC Filter Choke- Used primarily in filter applications or other tuned
circuits. Can also be used in conjunction with capacitors to reduce ripple
in DC circuits.
<p>
Swinging Choke- Similar to filter chokes except it has two inductance ratings
at two currents.
<p>
AC Reactors - AC choke, line/ load reactors are used primarily to limit
current. Both single phase and three phase versions are available. Also
they can be designed for 50, 60 or 50/60Hz.
<p>
<h4>ISOLATION TRANSFORMERS</h4>
(See power transformers)
<p>
<h4>MEDICAL TRANSFORMERS</h4>
Used in medical equipment to protect the patient from electrical shock and
potentially harmful leakage current. All transformers are double insulated
and use a 5 mil copper safety shield to protect against a catastrophic
failure on the primary or secondary side of the transformer in which case
the current is shunted to ground. Also included are reset-able thermal
fuses. Standard leakage current is less than 100uA. Transformers bare
the following marks: UL2601, UL544, CSA22.2 no 601.1, IEC2601, and TUV.
<p>
<h4>MERCURY VAPOR BALLAST</h4>
<p>
Mercury vapor ballasts are designed to drive tubular ultraviolet lamps.
The ballast serves two purposes. One, it generates a high enough voltage
to start the lamp. Two, after the lamp starts the ballast regulates the
current to the lamp. Since the mercury vapor lamp has a constant voltage
drop and the ballast regulates the current, the system produces constant
power.
<p>
There are two types of mercury vapor lamps. The most common is the medium
pressure lamp. This lamp series has been standardized and is available in
arc lengths of 1 inch to 120 inches. The other type of lamp is a mercury
vapor lamp with metal additives. The additives used in the lamp create
changes in the spectral output.
<p>
Ballast coming in sizes from 400 watts to 40KW in 50, 60, or 50/60Hz.
<p>
<table><tr><td>
<h4>POTENTIAL TRANSFORMER</h4>
<p>
Used primarily in a step down environment to monitor voltage. They are
designed for connection line-to-line or line-to-neutral in the same manner
as ordinary voltmeters. The secondary voltage bears a fixed relation with
the primary voltage so that any change in potential in the primary circuit
will be accurately reflected in the meters or other devices connected
across the secondary terminals. Potential transformers can be used with
voltmeters for voltage measurements or they can be used in combination with
current transformers for watt-meter or watt-hour meter measurements. They
are used also to operate protective relays and devices, and for many other
applications, Since they are used in a monitoring capacity, they generally
require much greater accuracy in design.</td><td>><img SRC="graph/transb.jpg" WIDTH="223" HEIGHT="249"></td></tr></table>
<p>
<table><tr><td>
<h3><font FACE="ARIAL">POWER TRANSFORMERS</font></h3>
<img SRC="graph/transa.jpg" WIDTH="320" HEIGHT="301"></td><td><font FACE="ARIAL">
Power transformers includes insulating or isolating transformers. These
terms are used to describe the "electrical isolation" of the primary and
secondary windings, or insulation between the two. Often a electro-static
copper shield is placed between windings to reduce electrical noise from
primary to secondary. A grounded electro-static shield provides a safety
factor preventing accidental contact between windings under faulty
conditions.<p>
Sizes: These are available in single phase or three phase up to 250KVA.
</font></td></tr></table>
<h4>SATURABLE REACTORS</h4>
<p>
<table><tr><td><font FACE="ARIAL">
Also known as Dial-A-Watt.
Used primarily with mercury vapor ballasts to vary the output current
(power) to the lamp.</font></td><td>
<img SRC="graph\lvbelec2.gif" WIDTH="399" HEIGHT="221"></td></tr></table>
<font FACE="ARIAL"> This is done by introducing a DC current to the
reactor. The reactor is connected across the capacitors on the ballast
and "swings" current from the ballast. Primary current to the ballast
remains constant regardless of power. </font>
<p>
<h4>STEP-UP \ STEP-DOWN TRANSFORMERS</h4>
<p>
Used to either increase or decrease incoming voltage. Many are designed to
do both (i.e. 120/208/240V in and 120/240V out) to handle worldwide
voltages. Another very common application would he to step down voltage
for DC rectification.
Sizes: Single phase units from approximately 10VA to 100KVA and up to 250KVA for three phase units. Most voltages can be accommodated. Voltages are typically under 6KV for small units and 10KV for large units.
<p>
<table><tr><td>
<font FACE="ARIAL"><h3>TOROIDAL TRANSFORMERS</h3>
<p>
Toroidal transformers include power and auto-transformers, as well as
inductors. Toroidal merely describes the geometric shape, similar to a
donut. These transformer are typically more efficient because of the low
core losses associated with a tape wound core, with no air gap. The shape
also allows a larger portion of the copper windings to be exposed to the
ambient air, enhancing cooling of the hotter copper windings versus the
cooler iron core in a laminated transformer.<p>
A toroid, when compared to a stacked laminated type transformer, would be
about 50% lighter and 50% lower in volume simply because it is more
efficient. Other advantages include low stray field, low mechanical hum,
reduced no load losses, easy mounting and flexible dimensions.</font>
</td><td><img SRC="graph/ulveco.jpg" WIDTH="189" HEIGHT="320"></td></tr></table>
<p>
<p>
<h4>VIBRATORY FEEDER COILS</h4>
The vibratory inductor is a unique application for a simple choke design, for
use in Vibratory Feeding Systems and Sorting Lines or Bowls.
<p>
Vibrations are set up, between an I-armature assembly and an IE-armature
assembly, through the changing magnetic field of the core. The E-armature
is usually secured to the solid equipment base, while the I-armature is
secured to the bowl or line to be vibrated. The two armatures are positioned
only a fraction of an inch from each other so that the E's and I ' s are
coupled through the magnetic field. This gap can be variable to change the
strength of vibrations. Coils can be provided potted or unpotted and are
available with heavy weldments for solid attachment to the vibratory unit.
Terminations are provided through flying leads, STO line cords, solder lugs,
or quick connect lugs.
<p>
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