Cramer Coil & Transformer Co., Inc.
Capabilities

Cramer is a leading designer and manufacturer of switching power magnetics. We have expertise ranging from low wattage surface mount components through large multi-kilowatt, chassis mount devices.  Cramer manufactures a variety of styles of magnetic devices that cover a broad range of potential customer applications. We supply to your specification or design and manufacture to your application conditions. Cramer has specialized, automated equipment to process a wide range of magnet wire, litz wire, foil, and foil assemblies. For board mount applications, most parts are wound with automated equipment on bobbins constructed from thermoplastic or thermoset materials. Bobbins offer excellent ground insulation, the most effective use of window area and the greatest amount of control for through hole or surface mounting. Cramer has many industry standard bobbins available or we can design and tool a bobbin to fit your specific application.

Shapes and Capabilities:

Ferrite: The main core material used is Ferrite. Ferrites are ceramic magnetic material comprised of ferric oxide and combinations of manganese, zinc or nickel. These different materials are used from audio to megahertz frequencies. Multiple vendors supply these materials in varying shapes, sizes and uses. Pulse, low power, and low isolation applications generally use the following shapes: "EE", "EP" and "RM". Higher power, higher isolation applications generally utilize the following shapes: "EE", "UU", "PQ", "ETD".

Present capabilities:
Size: No limitation
Power: 60 KVA(to date) or higher
Voltage: 2,000 Vrms maximum
Dielectric Strength (Hipot): 8,000 Vrms maximum

Filter, Switching Regulator, PFC Inductors: These inductors are supplied within the energy storage ranges (1/2 x L x I^2) of 1 Micro-Joule to 100 Joules. Molypermalloy (MPP), Gapped Ferrite and Powdered Iron materials are used. Size requirements and acceptable circuit losses determine the material. Molypermalloy offers the smallest size and least loss, but at the highest cost. Gapped Ferrite is larger than MPP, but is easily automated. Powdered Iron materials are the most cost effective, but are larger and have the highest losses. These are supplied through hole and surface mountable.

Common Mode Inductors: This type of multiple winding inductor is supplied on high permeability ferrite cores. The core types are "EE," "UU" and Toroids. The size of these inductors is determined by the required inductance, rated current and dielectric strength. They are supplied through hole or surface mountable.

Practical ranges per winding are as follows:
Inductance: 50 µhy to 20 mhy
Current: 10 ma to 10 amps
Hipot: 50 volts to 8000 volts

Toroids: The toroid, a circular non-radiating magnetic structure, is popular for its relatively low material cost and small size. The largest selection of magnetic materials are available in the toroidal shape. These materials include Silicon Iron, Nickel Alloys, Metallic Glass, Cobalt Alloys, Ferrite and Powdered Iron. Toroids are ideal for current sense transformer secondaries, input filter inductors, switching regulator inductors and common mode inductors.

Current Sense Transformer Secondaries: Construction ranges from 10 turns of 18 awg Teflon lead wire to 10,000 turns of 40 awg wire. Secondaries for sine, square or triangular waveforms within the frequency ranges of 20 Hz to 1 mHz are readily produced. These components are supplied with flying leads, through hole, surface or chassis mountable.

Present capabilities:
Power: limited by size
Voltage: 250 Vrms maximum
Dielectric Strength (Hipot): 8,000 Vrms maximum