EM-6402 HELMHOLTZ COIL SYSTEM. DC to 2kHz

Model 6402 Helmholtz coil system has twin 0.6 metre (2ft) diameter coils in a Helmholtz configuration and normally used as a Magnetic Field Immunity Test System or simply a low frequency magnetic field calibrator.  A magnetic field is produced by two coils that is essentially homogenous throughout the volume between the face of the coils and one-third diameter of the coils at it’s centre. The coils are supported by a non-metallic framework.  A rotating, height-adjustable pedestal is capable of holding articles weighing up to 15kg. The Coil has been initially calibrated at the NPL in terms of uT/amp at 50Hz. For the end user’s convenience NPL have also quoted a figure of uTesla per millivolt as measured across an installed shunt resistor with measuring terminal placed at the base of the Helmholtz. This was done at 60Hz and 2kHz. Typical examples of field using the crown LF amplifier can be seen on the graph  where the Crown amplifier (item 402) is hard driven with 3.1vrms input. At 1kHz, a field of 195 microTesla is achievable with the amplifier supplying 1.4amperes (hard driven). Built in on the base is the feed connector with 1Ω resistor for current verification. Also a 4metre  amplifier o/p supply lead. The device can arrive disassembled or assembled.

Specifications:

Electrical:

Coil Factor:    141.86 uTesla/ampere

Homogeneity:  ± 2% within a 25cm cube

Coil Impedance:  Approx. 0.5ohms DC;

Inductance:  7.47millihenrys

Self Resonance:   26kHz

Max I Input:  15 amps continuous

** 1 gauss  = 100µT = 160dBµT = 80 Amps/metre

Mechanical:

Diameter:         0.35m (2’)

Weight:          approximately 10kg (23lbs).