70053K Datasheet, PDF (10/28 Pages) List of Unclassifed Manufacturers – THE ADVANTAGES AND BENEFITS OF USING AMVECO TOROIDAL TRANSFORMERS

TECHNICAL AND APPLICATION NOTES (CONTINUED)
LINE FREQUENCY
Our standard transformers are designed to operate in 50 or 60Hz circuits.
Upon request, we furnish toroids with thinner laminations for operation
at frequencies to 2kHz. For even higher frequencies, cores are chosen
from such composite materials as ferrite or powdered metal.
Full Wave Bridge Tap
(FWCT) With Dual Outputs
APPLYING TOROIDS TO RECTIFIER POWER SUPPLIES
When used in rectifier circuits, the advantages of toroids may be opti-
mized if consideration is given to how they are applied. AC current in the
transformer’s secondary is not only influenced by the DC load current,
but, just as important, by the circuit configuration. Common circuit
configurations are shown as follows:
Full Wave Bridge (FWB)
FORM FACTOR (K)
IL(DC) = DC current load
IS(AC) = RMS current in secondary = KxIL(DC)
K = Form factor associated with circuit type
The “Form Factor” (K) is related to the rectifier circuit configuration and
the wave form of the current in the secondary.
IAC = K x IDC
Full Wave Center Tap (FWCT)
Typical form factor (K) values at capacitor input filter:
Rectifier Type
Form Factor (K)
FWB
1.8
FWCT
1.3
FWCT with choke input
0.7
FWCT with dual outputs
1.8
Full Wave Center Tap (FWCT) With Choke Input
AMVECO employs computer aided design techniques to optimize the
toroidal transformer parameters. Our computer program takes into
account the influence of the circuit Form Factor (K) as shown above.
When preparing specifications for toroids, it is important that the capaci-
tor value and the voltage drop across the regulator (if any) is furnished.
In some high current applications, a choke input filter will compound
savings because inductors yield a lower Form Factor (K). In these
circuits, the size of the transformer and the total capacitance are both
reduced.
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AMVECO Magnetics, Inc. • 10401 Westoffice Dr. • Houston, TX 77042 • [phone] • [phone] • Fax: [phone] • Email: [e-mail] • www.amveco.com