1. An electrical contactor comprising:
a first terminal connected to a pair of fixed contacts on opposite faces of a fixed conductive member;
a second terminal;
a pair of movable arms of electrically conductive material connected to the second terminal, and carrying movable contacts at an end remote from the connection to the second terminal, the movable contacts and the fixed contacts forming parallel switches and being arranged in first and second switch pairs; and
an actuating arrangement arranged to move the movable arms so as to open and close the switches,
wherein the actuating arrangement is arranged to close the first switch pair of contacts before closing the second switch pair of contacts.
2. The electrical contactor of claim 1, wherein the pair of movable arms are arranged in aligned opposition to each other such that their remote ends are on either side of the fixed conductive member, with the movable contacts aligned with the fixed contacts, and are separated by a predetermined gap over a major portion of their length.
3. The electrical contactor of claim 2, wherein the movable arms are preformed and preloaded so as to bias them towards each other to engage the fixed contacts with a preset contact pressure keeping the contacts normally closed in the absence of a force separating the movable arms.
4. The electrical contactor of claim 2, wherein the actuating arrangement includes a wedge shaped member disposed between inner inclined surfaces of the movable arms, arranged to separate the movable arms so as to open the contacts, the wedge shaped member being movable from a first position in which it separates the movable arms, to a second position where it allows the arms to move freely towards each other.
5. The electrical contactor of claim 4, wherein the actuating arrangement comprises an electromagnetic actuator coupled to the wedge shaped member and the movable member, the electromagnetic actuator effecting movement of the wedge shaped member and the movable member, between the first and second positions.
6. The electrical contactor of claim 1, further comprising ferrous plates attached on the outer faces of the movable arms, wherein the arrangement of the fixed member and movable arms being such that when the contacts are closed, current flowing through the movable arms and the ferrous plates produces induced magnetic-field attraction forces between the movable arms that urges the movable arms towards each other, thereby increasing the force pressing the movable contacts against the fixed contacts.
7. The electrical contactor of claim 6, wherein the ferrous plates are attached to the movable arms along their formed length, whereby when the contacts are closed, higher current flowing through the movable arms induces magnetic fields in the ferrous plates, generating a magnetic force of attraction urging the contacts closed.
8. The electrical contactor of claim 1, wherein the contactor is a two pole contactor having a pair of first and second terminals, a pair of fixed conductive members and two pairs of movable arms.
9. The electrical contactor of claim 1, wherein each movable arm comprises a plurality of longitudinal sections, each provided with a movable contact at the remote end and arranged to engage with a corresponding fixed contact, the current flow in the arms being substantially equally divided between the sections thereof.
10. The electrical contactor of claim 1, wherein the contacts of the first pair of switching contacts are larger than the contacts of the second pair of switching contacts.
11. The electrical contactor of claim 1, wherein the contacts of the first pair of switching contacts have a thicker top-layer of silver alloy than the contacts of the second pair of switching contacts.
12. The electrical contactor of claim 1, wherein the contacts of at least the first pair of switching contacts have a top-layer of silver alloy with tungsten-oxide additive inclusions in the silver matrix.
13. The electrical contactor of claim 1, wherein the contacts of at least the first pair of switching contacts have a tungsten rich top-layer.
14. A 2-pole electrical contactor comprising:
a first terminal connected to a fixed contact on a face of a first fixed conductive member;
a second terminal;
a first movable arm of electrically conductive material connected to the second terminal, and carrying a movable contact at an end remote from the connection to the second terminal, the movable contact and the fixed contact forming a first switch and being arranged in first switch pair of contacts;
a third terminal connected to a fixed contact on a face of a second fixed conductive member;
a fourth terminal;
a second movable arm of electrically conductive material connected to the fourth terminal, and carrying a movable contact at an end remote from the connection to the fourth terminal, the movable contact and the fixed contact forming a second switch and being arranged in a second switch pair of contacts; and
an actuating arrangement arranged to move the movable arms so as to open and close the switches,
wherein the actuating arrangement is arranged to close the first switch pair of contacts after closing the second switch pair of contacts.
15. The electrical contactor of claim 14, further comprising a plurality of first movable arms and a plurality of second movable arms.
16. The electrical contactor of claim 14, wherein each movable arm comprises a plurality of longitudinal sections, each provided with a movable contact at the remote end and arranged to engage with a corresponding fixed contact, the current flow in the arms being substantially equally divided between the sections thereof.
17. The electrical contactor of claim 14, wherein the contacts of the first pair of switching contacts are larger than the contacts of the second pair of switching contacts.
18. The electrical contactor of claim 14, wherein the contacts of the first pair of switching contacts have a thicker top-layer of silver alloy than the contacts of the second pair of switching contacts.
19. The electrical contactor of claim 14, wherein the contacts of at least the first pair of switching contacts have a top-layer of silver alloy with tungsten-oxide additive inclusions in the silver matrix.
20. The electrical contactor of claim 14, wherein the contacts of at least the first pair of switching contacts have a tungsten rich top-layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-11. (canceled)
12. A method of carrying out automated attenuated total reflectance (ATR) spectral measurement, comprising:
differentiating an acquired image in a spectral domain;
restricting a spectral range of the acquired image;
subtracting an average absorbance from the restricted image data; and
applying a principal component analysis to extract significant spectral features from the restricted image data.
13. The method of claim 12, further comprising color compositing the extracted features for display to a user.
14. The method of claim 12, wherein the differentiating step comprises smoothing the acquired image to reduce noise.
15. A method of carrying out automated ATR spectral analysis, comprising:
acquiring a spatial image of a sample;
differentiating the acquired image in the spectral domain;
restricting the spectral range of the image;
subtracting an average absorbance from the restricted image data;
applying a principal components analysis to extract the most significant spectral features; and
displaying a spatial image showing the most significant spectral features of the sample to a user.
16. The method of claim 15, further comprising color compositing the extracted components for display to the user.
17. The method of claim 15, wherein the differentiation step includes smoothing the acquired image to reduce noise.
18. An imaging ATR system, comprising:
an imaging microscope;
image processing means; and
an interface for displaying processed images to a user,
wherein the system is constructed and arranged to carry out automated ATR spectral analysis by:
acquiring an image of a sample;
differentiating the acquired image in the spectral domain;
restricting the spectral range of the image;
subtracting an average absorbance from the restricted image data;
applying a principal components analysis to extract the most significant spectral features; and
displaying a spatial image showing the most significant spectral features via the interface.
19. The imaging ATR system of claim 18, wherein the system is further arranged for color compositing the extracted components for display to the user.
20. The imaging ATR system of claim 18, wherein the differentiation step includes smoothing the acquired image to reduce noise.