Low weight and low excitation force magnetotorquer

Details Low weight and low excitation force magnetotorquer Low weight and low excitation force magnetotorquer

1999-06-21

2002-04-30

Enad, Elvin (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S181000

Reexamination Certificate

active

06380657

ABSTRACT:

FIELD OF THE INVENTION
The invention is in the field of magnetotorquers particularly suitable for use in earth orbiting satellites for steering and stabilization purposes.
BACKGROUND OF THE INVENTION
A magnetotorquer hereinafter referred to a “MTQ” has a ferromagnetic core with an excitation coil wound therealong through which a current passes for generating a total magnetic dipole M for imparting a torque T given by the vector product of {overscore (T)}={overscore (M)}×{overscore (B)}
earth
.
The total magnetic dipole M is derived as follows:
M
=
1
μ
0
⁢
∫
v
⁢
BdV
≈
μ
·
n
·
I
·
V
where &mgr;
0
is the permeability of free space, B is the local flux density, &mgr; is the effective permeability, n-I is defined as the excitation force and is the product of the number of windings per total core length n and the excitation current I, and V is the core's volume.
A convention MTQ has a right cylindrical core with an excitation coil uniformly wound therealong and whose distribution of the total magnetic flux &phgr; therealong is characterized by a maximum flux density value at its core's center and a flux density value of less than 2% of the maximum value at its core's ends.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, there is provided a magnetotorquer comprising a ferromagnetic core with an excitation coil more compacted at its central portion than at at least one of its lateral portions.
Compacting the MTQ's excitation coil at its central portion increases the local flux density thereat in comparison to a conventional MTQ assuming the same excitation force. The advantage afforded thereby is that the same total magnetic dipole can be obtained with a smaller excitation force effected by either a smaller current consuming less power or less windings which weigh less.
In accordance with a second aspect of the present invention, there is provided a magnetotorquer comprising a ferromagnetic core with an excitation coil wound therealong, said core having a central portion intermediate to lateral portions, at least one lateral portion having a smaller material cross section area than said central portion.
Reducing the material cross section area of preferably both of a core's lateral portions has the effect of increasing the local flux density thereat in comparison to a conventional MTQ assuming the same excitation coil and excitation force without, however, reducing its total magnetic dipole. The advantage afforded thereby is that material can be removed from the core thereby reducing its overall weight.


REFERENCES:
patent: 399403 (1889-03-01), Higham
patent: 3400328 (1968-09-01), Penn et al.
patent: 3667035 (1972-05-01), Slichter
patent: 3725705 (1973-04-01), Borinski
patent: 3731752 (1973-05-01), Schad
patent: 3766787 (1973-10-01), Irvine
patent: 4114841 (1978-09-01), Muhlfelder et al.
patent: 4117602 (1978-10-01), Lapeyre
patent: 4157495 (1979-06-01), Grover et al.
patent: 4458248 (1984-07-01), Lyasko
patent: 4617516 (1986-10-01), Schenck
patent: 4661753 (1987-04-01), McBrien et al.
patent: 4746085 (1988-05-01), Bruderle
patent: 4939459 (1990-07-01), Akachi et al.
patent: 5220339 (1993-06-01), Matsushita
patent: 5289129 (1994-02-01), Joseph
patent: 6121770 (2000-09-01), Sudo
patent: 0671323 (1995-09-01), None
patent: 0777127 (1997-06-01), None
patent: 0969485 (2000-01-01), None
patent: 1209196 (1960-02-01), None
patent: 1290779 (1962-09-01), None
patent: 1329084 (1963-12-01), None
patent: 2718105 (1995-10-01), None
patent: 1042077 (1966-09-01), None
Bozorth, R.M. et al. “Demagnetizing Factors of Rods.” Journal of Applied Physics, vol. 13 (1942 pp. 320-326.
Cambridge Aerospace Series, “Spacecraft Dynamics and Control”, by Marcel J. Sidi, p. 397-398 (before 1998).
Bird, M. D., et al. “Design and Construction of 12-MW Magnets at the NHMFL.”
IEEE Transactions on Magnetics, vol. 30, No. 4 (1994) pp. 2200-2203.
English Summary of FR 1290779 Dated Sep. 7, 1962.
English Summary of FR 1329084 Dated Dec. 16, 1963.
English Summary of FR 1209196 Dated Feb. 29, 1960.

Affiliated with

Also associated with

Rating

Low weight and low excitation force magnetotorquer does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Low weight and low excitation force magnetotorquer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low weight and low excitation force magnetotorquer will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2855512