300 mm Helmholtz Coils - Versin en Castellano (clic aqu)

Ferronato - BH300-3-A

---  Desktop set of three pairs of Helmholtz coils for laboratory and general purposes.

---  Suited for many magnetic measurements and experiments, in DC and AC.

  • Same generating field ratio for each of the three pairs, with a round value easy to handle: 500 T/A

  • Accurately made, with error smaller than 1% in the generated field.

  • The coil arrangement can be modified with relative facility thanks to its simple support and its joins by screws.

  • Coils on non-magnetic aluminium alloy forms.

  • Each aluminium form provides a usable extra turn, with connections at the terminal block. An application example is the generation of a small magnetic field (DC or AC) to modulate the main one. Also it can be wired to generate small gradients. (- Click here for more details -)

  • The aluminium forms also act like electrostatic screens.

  • The coils can undergo heatings by currents to at least 100 C without damage.

  • Robust construction but with a reasonable weight.

  • Totally constructed with non-ferromagnetic materials.

  • Excellent quality/price ratio.

  • There are available versions of one and two axes, with similar characteristics:

    • BH300-1A-A, on one axis, horizontal, with only the X pair.

    • BH300-1B-A, on one axis, vertical, with only the Z pair.

    • BH300-2A-A, on two axes, horizontal/horizontal,  with the X and Y pairs.

    • BH300-2B-A, on two axes, horizontal/vertical, with the  X and Z pairs.






Field/Current ratio 500 T/A (5.0 Gauss/A). For each pair, X, Y or Z. Maximum error: 1%. In DC and AC.
Maximum field 2.0 mT (20 Gauss) in a steady mode / 3.0 mT (30 Gauss) during 2 minutes. Each pair.
Maximum current 4.0 A in a steady mode / 6.0 A during 2 minutes (start temperature: 20 C). Each pair.
Isolation voltage 250 V DC minimum, between windings and their forms and between pairs. Tested to 500 V DC.
Magnetic field homogeneity Differences smaller than 1% with respect to the centre, in a spherical volume of 70 mm of diameter, centred in the coils. Differences smaller than 5% in a spherical volume of 100 mm of diameter. Volumes to 1% and 5% greater on some directions.
Orthogonality error < 0.2, or < 0.1 optionally.
Connection Single row, twelve positions, barrier strip terminal block, with M4 brass screws ( 4 mm).
Max. working temp. 80 C for the set / 100 C for the coils, as measured on its surface.
Coil cross section Winding: 8.5 x 10 mm, maximum. Total (form): 10 x 13 mm
Materials Enamelled copper wire windings, filled with epoxy resin. Coil forms of aluminium alloy, with internal isolating layer and connecting plates of resin/glass fibre (FR4) with PVC covers. Stand support pillars and coil brackets in Acetyl ("Delrin"), with upper and lower boards in foamed PVC. Screws of nickel-plated brass and nylon.
Maximum dimensions Height 364 mm x Wide 309 mm x Depth 276 mm.
Weight 4.5 kg for the BH300-3-A set (lower for BH300-1A/B-A and BH300-2A/B-A).
Accessories Delivered with Instructions of Use in Spanish and English.
Warranty Two years.

Specifications FOR EACH COIL PAIR

  X pair (large) Y pair (medium) Z pair (small)
Effective diameter: 300 1 mm 266 1 mm 237 1 mm
Turns number: 83 74 66
DC Resistance, at 20 C:                                      (1) 4.21 Ω  3% 3.35 Ω 3% 2.66 Ω 3%
Self-inductance: 10.4 mH  5% 7.1 mH  5% 4.9 mH  5%

Self-resonance Frequency:

(With one form end connected to one coil end)

~ 25 kHz ~ 34 kHz ~ 42 kHz
Secondary field generated by the forms when used as coils (Xs, Ys, Zs):                                              (2) 6.0 T/A  1% 7.1 T/A  1% 7.7 T/A  1%

(1) - Resistance measured at the general connection block.

(2) - We call this constructive idea "In-Circuit Coils Forms".  - Click here for more details -


Version: BH300-3-A BH300-2A-A BH300-2B-A BH300-1A-A BH300-1B-A
Included coil pairs: X, Y, Z X, Y X, Z X Z

- These specifications are subject to change without prior notice -

- These units are supplied mounted and ready for use, in a cardboard box.

- BH1300-3-A model page - click here -

- BH300-3-A model page - click here -

- To obtain this page in PDF format,click here -


For any enquiry, please, do not hesitate in contact us:


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  Updated: 06 Jan 2016