What is claimed is:
1. An apparatus to control a brushless Direct Current (DC) motor equipped with a rotator, the apparatus comprising:
a converting unit to convert Alternating Current (AC) power to polyphase AC power and supply the polyphase AC power to the brushless DC motor;
a rotator operation detecting unit to detect operation information of the rotator; and
a control unit to predict a phase commutation time of the polyphase AC power and control an ignition time of an ignition phase current to be earlier than the phase commutation time.
2. The brushless DC motor control apparatus according to claim 1, wherein the control unit predicts the phase commutation time of the polyphase AC power using either the operation information of the rotator or variation information of the polyphase AC power supplied to the brushless DC motor, or both.
3. The brushless DC motor control apparatus according claim 2, wherein the operation information of the rotator is either position information or speed information of the rotator, or both.
4. The brushless DC motor control apparatus according to claim 2, wherein the variation information of the polyphase AC power is zero crossing point detection information of an ignition phase voltage supplied to the brushless DC motor.
5. The brushless DC motor control apparatus according to claim 1, wherein the control unit controls all phase currents of the polyphase AC power, supplied to the brushless DC motor, to be conducted during a period between the ignition time of the ignition phase current and the phase commutation time.
6. The brushless DC motor control apparatus according to claim 1, wherein the converting unit comprises:
a converter to convert the AC power to DC power;
an inverter to convert the DC power to the polyphase AC power; and
a capacitor to connect between the converter and the inverter.
7. The brushless DC motor control apparatus according to claim 6, wherein the control unit controls the ignition time of the ignition phase current supplied to the brushless DC motor by generating an inverter control signal and outputting the inverter control signal to the inverter.
8. A method to control a brushless DC motor equipped with a rotator and supplied with polyphase AC power, the method comprising:
predicting an ignition phase commutation time of the polyphase AC power using operation information of the rotator; and
controlling an ignition time of an ignition phase current to be earlier than the phase commutation time.
9. The brushless DC motor control method according to claim 8, wherein the phase commutation time of the polyphase AC power is predicted using either the operation information of the rotator or variation information of the polyphase AC power supplied to the brushless DC motor, or both.
10. The brushless DC motor control method according claim 9, wherein the operation information of the rotator is either position information or speed information of the rotator, or both.
11. The brushless DC motor control method according to claim 9, wherein the variation information of the polyphase AC power is zero crossing point detection information of an ignition phase voltage supplied to the brushless DC motor.
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. A crown element for securing a packing in a mass transfer column comprising
an elongate sheet having a thickness of from 0.05 to less than 0.2 mm and including a wall element, a roof element extending from said wall element with a first bending line between said wall element and said roof element and a bottom element extending from said wall element with a second bending line between said wall element and said bottom element,
said roof element having a plurality of incisions to separate said roof element into a plurality of elastically deformable roof element segments,
said bottom element having a plurality of grooves to separate said bottom element into a plurality of elastically deformable segments wherein the number of said incisions is smaller than the number of said grooves, and
said wall element comprises a plurality of first surfaces of triangular shape, a plurality of second surfaces of trapezoidal shape disposed in alternating manner with said first surfaces longitudinally thereof and a plurality of bending lines each said line being disposed between a respective first surface and a respective second surface.
2. A crown element in accordance with claim 1 wherein said roof element has a roof element edge and wherein said incisions extend from said roof element edge to said first bending line.
3. A crown element in accordance with claim 2 wherein at least some of said incisions cover only a portion of the distance between said roof element edge and said first bending line.
4. A crown element in accordance with claim 1 wherein said bottom element has a bottom element edge and wherein said grooves extend from said bottom element edge to said second bending line.
5. A crown element in accordance with claim 1 wherein said wall element has at least one protrusion thereon.
6. A crown element in accordance with claim 1 wherein said roof element is arranged at an angle of 5 to 60\xb0 relative to said wall element.
7. A crown element in accordance with claim 1 wherein said roof element is composed of a plurality of roof element segments, each said roof element segment having a length in a the range of from 40 to 120 mm.
8. A crown element in accordance with claim 1 wherein said roof element has a height in a range of from 15 to 40 mm.
9. A crown element according to claim 1 wherein at least a portion of said grooves is arranged in staggered relation to said incisions.
10. A crown element in accordance with claim 1 wherein said roof element has a curved roof clement edge and said bottom element has a curved bottom element edge.
11. In combination,
a mass transfer column comprising a tubular wall;
a packing disposed within said column wall; and
a crown element arranged between said column wall and said packing for securing said packing in said mass transfer column, said crown element including an elongate sheet having a roof element, a wall element and a bottom element, said wall element being arranged between said roof element and said bottom element, a first bending line between said roof element and said wall element, a second bending line between said wall element and said bottom element, said roof element having a plurality of incisions, said bottom element having a plurality of grooves and characterized in that the number of said incisions is smaller than the number of said grooves and at least one of said wall element, said roof element and said bottom element has a thickness of 0.05 to less than 0.2 mm and said wall element comprises a plurality of first surfaces of triangular shape, a plurality of second surfaces of trapezoidal shape disposed in alternating manner with said first surfaces longitudinally thereof and a plurality of bending lines, each said line being disposed between a respective first surface and a respective second surface.
12. The combination according to claim 11 wherein said wall element is in contact with said packing and spaced from said column wall, said roof element and said bottom element extending from said wall element at an oblique angle relative to said wall element such that said roof element extends into the direction of said column wall and said bottom element extends into the direction of said packing whereby said crown element is elastically deformable as to exert a holding force onto said packing to fix said packing within said column wall in a position as to enable a mass transfer to be performed when said column is in an operational state.
13. The combination according to claim 12 wherein said packing comprises a plurality of packing segments.
14. The combination according to claim 12 wherein said bottom element is at least partially squeezed between a first and a second packing element.