Electric motor

Details Electric motor Electric motor

1998-10-02

2000-03-28

Ramirez, Nestor

Electrical generator or motor structure

Dynamoelectric

Rotary

310242, 310246, 310248, 310249, 310239, H02K 1100

Patent

active

060435763

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

Electric motors with a magnetic pole wheel arranged on the motor armature shaft, fixed against relative rotation, as the signal emitter, and with an associated signal receiver fixed in place on the housing, are commonly known prior art. Signal emitter and signal receiver act together as a sensor in order to detect, for example, the direction of rotation, rpm, speed of the motor armature shaft and other parameters of the motor operation.


SUMMARY OF THE INVENTION

In accordance with the present invention, the signal conducting means contain magnetically conducting material and conduct the signal of the at least one magnet field-generating means to the at least one magnetic field sensor, and the at least one current conducting means are arranged essentially along the signal conducting means.
The electric motor in accordance with the present invention has the advantage that the magnetic field sensor can be arranged remote from the means generating the magnetic field, but still dependably detects the magnetic field of the magnetic field-generating means. By the arrangement of the signal conducting means essentially along the current conducting means, the field conducted to the magnetic field sensor is affected not at all or only minimally by the magnetic field of the current flowing in the current conducting means if, the effective magnetizing direction, i.e. the magnetization generated by the magnetic field-generating means, extends along the signal conducting means. Tests which have been conducted have shown that, for example in the course of operating customary commercial small motors at currents of approximately 30 A, the magnetic field accompanying the currents has a flow density of an order of magnitude of 20 mT. This interference field can-in particular when the electric motor is switched on-lead to false measurements in the magnetic field sensor. Such false measurements are prevented by the arrangement in accordance with the invention.
In accordance with an embodiment of the invention, the current conducting means and the signal conducting means respectively are constituted as individual components. The two components can be arranged in a sandwich structure, for example. Since the current conducting means are essentially arranged along the signal conducting means, the lines of flux of the field accompanying the signal conducting means extend perpendicularly in respect to the effective magnetizing direction. In this case it is possible, with a suitable magnetic field sensor selection and arrangement, to specifically evaluate the effective magnetic field without the superimposition of interference fields.
In another embodiment of the invention, the current conducting means are arranged on the surface of the signal conducting means. Since the current conducting means enclose the signal conducting means almost completely, the magnetic field accompanying the current flow is vanishingly small in the interior of the signal conducting means (Faraday cage effect). Therefore there is hardly any interference with the effective magnetic field in the signal conducting means.
Further advantageous further embodiments and designs of the invention ensue from the further dependent claims and from the exemplary embodiments.


BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a shows an electric motor in accordance with the invention in a partially sectional view, FIG. 1b a portion, rotated by 180.degree. C. in respect to FIG. 1a, of a brush holder of the electric motor in FIG. 1,
FIG. 2 shows the brush holder of the electric motor of the invention in a view from above,
FIG. 3a shows a first exemplary embodiment of a current conductor arranged along a signal conducting means in a view from above, FIG. 3b shows the first exemplary embodiment in a lateral view,
FIG. 4a shows a second exemplary embodiment of a signal conducting means and a current conducting means in a view from above, and FIG. 4b shows the second exemplary embodiment in a lateral view.


DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1

REFERENCES:
patent: 4329605 (1982-05-01), Angi et al.
patent: 4475053 (1984-10-01), Mayer

Affiliated with

Also associated with

Rating

Electric motor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Electric motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric motor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1328439