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Custom Toroidal Transformers
Design Considerations - Finishes
Polyester tape: A proven, economical option.
Metal can or plastic enclosure: For environmental protection and / or magnetic shielding.
Varnishing and vacuum impregnation: Good protection; recommended for harsh environments. Protective against humidity and pollution.  Avel offers full vacuum and pressure varnish impregnation, as well as envelope dipping with mold-resistant polymers and protective barriers. Impregnation and dipping can be carried out with either standard solvent-based coil varnishes or solventless epoxy varnishes. Please call if you have an unusual environmental requirement.
Design Considerations - Terminations
Flying solid lead wires: Most cost-effective.

Flying stranded lead wires: Withstand repeated flexure better than solid wires; may be required if connectors or terminals are to be crimped to wires.  We can supply transformers with connectors or terminals to your specifications attached to lead wires-just indicate manufacturer and part number on request for quotation form.

Tabs (not shown): For quick connections and disconnection using standard wire terminals.
Pins for PCB mounting: Save time in assembly; standard and custom pin layouts available.
Design Considerations - Mounting Options
Dished mounting plate with foam pads and bolt: The most economical mounting option.
Epoxy resin-filled center with threaded bushing or clearance hole: Resin can be recessed for the bolt head to allow flush mounting. Ideal for minimizing height; more rugged than the standard (dished plate) mounting kit.
Metal mounting frame (H-frame): Suggested for 1000VA and above and / or applications with extremes of shock and vibration.
L-bracket or omega bracket: For vertical mounting.
Markings and international standards:  Transformers can be certified to and marked for:
  • UL506/CSA 22.2, No. 66; UL1411/CSA 22.2 No. 1-94; UL1950/CSA 22.2 No. 950-95; UL2601 (UL544)/CSA 22.2 No.601.1; CE marked and tested in accordance with EN61558 (replacing EN60742), EN60065, EN60950, BS415, VDE0550.
Minimizing Noise:  Although toroidal transformers inherently exhibit very low radiated field, the following may be considered to reduce noise further in very sensitive applications.
  • Steel or Mu-metal band: Added to periphery under finishing tape.
  • Metal can: For complete or partial enclosure.
  • Resin filling can also dampen acoustic noise.

Transformers can also be constructed using special manufacturing techniques and tested to ensure 100% acceptable noise levels.

Custom Leads and Terminations: Reduce your assembly labor costs-let us supply transformers with connectors or terminals to your specifications attached to lead wires.  Just indicate manufacturer and part number on the request for quotation form.