1. A circuit arrangement for operating a high-pressure discharge lamp having a straightened arc, comprising:
at least one first and one second electronic switch in a first half-bridge;
a supply voltage connection and a reference ground connection for supplying the half-bridge arrangement with a direct voltage signal;
a load circuit which comprises a lamp choke and a blocking capacitor and is coupled on one side to the half-bridge center point and on the other side to at least one terminal for connecting the high-pressure discharge lamp;
a drive circuit for providing at least one first and one second drive signal for the first and the second electronic switch,
wherein the first and second drive signal are pulse-width-modulated signals having the same frequency, wherein the pulse duty factor of the two drive signals and the phase angles of the two drive signals relative to each other can be set independently of each other in each case, and the two drive signals can each be inverted in a low-frequency cycle.
2. The circuit arrangement as claimed in claim 1, wherein the load circuit has a blocking capacitance consisting of one blocking capacitor which is connected in series with the at least one terminal of the high-pressure discharge lamp.
3. The circuit arrangement as claimed in claim 1, wherein the load circuit has a blocking capacitance consisting of two block capacitors which are each connected symmetrically from at least one terminal of the high-pressure discharge lamp to the supply voltage connection and the reference ground connection in each case.
4. The circuit arrangement as claimed in claim 1, wherein the circuit arrangement has a second half-bridge which has a third and a fourth electronic switch for driving a resonance circuit for igniting the gas discharge lamp and is arranged between the center point of the first half-bridge and a circuit ground.
5. The circuit arrangement as claimed in claim 4, wherein the third and the fourth electronic switch of the second half-bridge can likewise be driven by the drive signal.
6. A method for operating a high-pressure discharge lamp having a circuit arrangement as claimed in claim 1 the following steps being performed during the operation of the gas discharge lamp:
driving the first and second electronic switch with a first and second drive signal, the drive signals being pulse-width-modulated signals having the same frequency;
varying or setting the pulse duty factors of the drive signals;
setting the phase angle of the two drive signals relative to each other,
inverting the two drive signals in a low-frequency cycle.
7. The method as claimed in claim 6, wherein the phase angle of the two drive signals relative to each other is varied during operation.
8. The method as claimed in claim 6, wherein the pulse duty factors of the drive signal for in each case the first electronic switch and the second electronic switch are set separately and independently of each other.
9. (canceled)
10. (canceled)
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 gearbox for vertical orientation for driving an auger in a vertical mixer, the gearbox comprising:
an input interface for receiving power output from a power source;
gearing in communication with the input interface;
an output shaft in communication with the gearing for outputting power via the top of the gearbox to the auger;
an oil lubricated bearing for guiding the output shaft;
an internal oil reservoir in fluid communication with the gearing, the output shaft and the oil lubricated bearing wherein a minimum oil fill level at least covers the oil lubricated bearing; and
a breather bore extending through the output shaft and exiting the top of the output shaft via a top port and exiting a side of the output shaft via a bottom port, the bottom port in fluid communication with the internal oil reservoir,
wherein a maximum oil fill level is above the minimum oil fill level.
2. The gearbox of claim 1, wherein the maximum oil fill level is above the bottom port of the breather bore.
3. The gearbox of claim 1, wherein the maximum oil fill level is at the top of the internal oil reservoir.
4. The gearbox of claim 1 further comprising a breather line extending upwards from the top port.
5. The gearbox of claim 1 further comprising an external oil reservoir and an oil fill line in communication between the external oil reservoir and the internal oil reservoir, the external reservoir situated such that the bottom of the external reservoir is below the minimum oil fill level and the top of the reservoir is above the maximum oil fill level.
6. The gearbox of claim 1 further comprising an external oil reservoir mounted above the top port, the external reservoir in fluid communication with the top port such that oil is delivered to the internal oil reservoir via gravity, and wherein the maximum oil fill level is above the top port.
7. The gearbox of claim 1 further comprising an internal grease passage in the gearbox casing, the internal grease passage in fluid communication with a grease lubricated bearing positioned towards the top of the output shaft and a grease port positioned proximate the bottom of the gearbox.
8. A vertical mixer for mixing bulk material, the vertical mixer comprising:
a mixing chamber defined by a floor and upending wall, the mixing chamber for receiving bulk material;
a vertical auger for mixing the bulk material, the vertical auger including a hollow auger tube with flighting affixed thereto;
a gearbox for driving the auger, the gearbox vertically mounted through the floor of the mixing chamber and including a top portion captured within the auger tube and a bottom portion extending below the floor, the gearbox comprising:
an input interface for receiving power output from a power source;
gearing in communication with the input interface;
an output shaft in communication with the gearing for outputting power via the top of the gearbox to the auger;
an oil lubricated bearing for guiding the output shaft;
an internal oil reservoir in fluid communication with the gearing, the output shaft and the oil lubricated bearing wherein a minimum oil fill level at least covers the oil lubricated bearing; and
a breather bore extending through the output shaft and exiting the top of the output shaft via a top port and exiting a side of the output shaft via a bottom port, the bottom port in fluid communication with the internal oil reservoir,
wherein a maximum oil fill level is above the minimum oil fill level.
9. The vertical mixer of claim 8, wherein the maximum oil fill level is above the bottom port of the breather bore.
10. The vertical mixer of claim 8, wherein the maximum oil fill level is at the top of the internal oil reservoir.
11. The vertical mixer of claim 8 further comprising a breather line extending upwards from the top port into the auger tube.
12. The vertical mixer of claim 8, wherein the input interface and an oil fill port in fluid communication with the internal oil reservoir are positioned below the floor of the mixing chamber.
13. The vertical mixer of claim 8 further comprising an external oil reservoir and an oil fill line in communication with the internal reservoir, the external reservoir situated such that the bottom of external reservoir is below the minimum oil fill level and the top of the external reservoir is above the maximum oil fill level.
14. The vertical mixer of claim 8 further comprising an external oil reservoir mounted above the top port and within the auger tube, the external reservoir in fluid communication with the top port such that oil is delivered to the internal oil reservoir via gravity, and wherein the maximum oil fill level is above the top port.
15. The vertical mixer of claim 8 further comprising an internal grease passage in the gearbox casing, the internal grease passage in fluid communication with a grease lubricated bearing positioned towards the top of the output shaft and a grease port positioned proximate the bottom of the gearbox.
16. The gearbox of claim 2, wherein the maximum oil fill level is at the top of the internal oil reservoir.
17. The gearbox of claim 9, wherein the maximum oil fill level is at the top of the internal oil reservoir.
18. The gearbox of claim 16 further comprising a breather line extending upwards from the top port.
19. The gearbox of claim 17 further comprising a breather line extending upwards from the top port.
20. The gearbox of claim 19 further comprising an external oil reservoir and an oil fill line in communication between the external oil reservoir and the internal oil reservoir, the external reservoir situated such that the bottom of the external reservoir is below the minimum oil fill level and the top of the reservoir is above the maximum oil fill level.