US5086265A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical circuit for a centrifuge
Assignee: Thermo Electron LED GmbH
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Filing: 1991-05-06
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Granted: 1992-02-04
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Expires: 2011-05-06
Abstract
Abstract To control the speed of an alternating-current drive capacitor motor of a centrifuge, the motor is connected to the bridge arm of a single-phase inverter. The bridge arm is connected at each of its ends to the midpoints of a series circuit of two capacitors and two field-effect transistors, these series circuits being connected in parallel with one another and connected to the output of a rectifier operated by the a.c. voltage supply. During operation, the capacitors are discharged by means of triggering the field-effect transistors alternately via the capacitor motor, the triggering being performed via a microprocessor serving as a pulse generator.
Inventors
- 👤 Rudiger Uhiendorf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:48
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/04; H02P2201/00; H02P2201/05
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
127 words
A system for preselecting the speed of a capacitor electric motor of a centrifuge, comprising: a source of direct current a first series circuit including two series connected field effect transistors, each having a control input for switching the corresponding transistor to an on and off condition, the transistors having a common connection for connecting to one terminal of the motor; a second series circuit including at least two series connected capacitors having a common connection for connecting to a second terminal of the motor; the first and second series circuit being connected in parallel across the direct current source; and a pulse generator having an output connected to the control input of both field effect transistors for applying spaced control pulses alternately to the two transistors.
Claim 2
Independent Claim
127 words
A system for preselecting the speed of a capacitor electric motor of a centrifuge, comprising: a source of direct current a first series circuit including two series connected field effect transistors, each having a control input for switching the corresponding transistor to an on and off condition, the transistors having a common connection for connecting to one terminal of the motor; a second series circuit including at least two series connected capacitors having a common connection for connecting to a second terminal of the motor; the first and second series circuit being connected in parallel across the direct current source; and a pulse generator having an output connected to the control input of both field effect transistors for applying spaced control pulses alternately to the two transistors.
Claim 3
Dependent Claim
32 words
The system of claim 1, wherein the control input of each field effect transistor includes a first input for turning on the transistor and a second input for turning off the transistor.
Claim 4
Dependent Claim
47 words
The system of claim 1, wherein the control input includes at least a first photodiode for each of the transistors responsive to light pulses for controlling the corresponding transistor; and a light emitting diode responsive to the pulses of the pulse generator for providing said light pulses.
Claim 5
Dependent Claim
47 words
The system of claim 2, wherein the control input includes at least a first photodiode for each of the transistors responsive to light pulses for controlling the corresponding transistor; and a light emitting diode responsive to the pulses of the pulse generator for providing said light pulses.
Claim 6
Dependent Claim
31 words
The system of claim 3, wherein the at least first diode is connected in series with a second diode across a gate and source of each of the field effect transistor.
Claim 7
Dependent Claim
31 words
The system of claim 4, wherein the at least first diode is connected in series with a second diode across a gate and source of each of the field effect transistor.
Claim 8
Dependent Claim
58 words
The system of claim 5, further comprising a phototransistor having a collector and emitter, the collector and emitter being connected in parallel with the series connected first and second diodes; and a second light emitting diode responsive to turn-off pulses of the pulse generator for controlling the phototransistor to operate the field effect transistor to the off condition.
Claim 9
Dependent Claim
58 words
The system of claim 6, further comprising a phototransistor having a collector and emitter, the collector and emitter being connected in parallel with the series connected first and second diodes; and a second light emitting diode responsive to turn-off pulses of the pulse generator for controlling the phototransistor to operate the field effect transistor to the off condition.
Claim 10
Dependent Claim
39 words
The system of claim 1, further comprising a third field effect transistor having a control input for receiving a braking signal that is connected across the second terminal of the motor and one pole of the direct current source.
Claim 11
Dependent Claim
12 words
The system of claim 1, wherein the pulse generator includes a microprocessor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-02-03 | 1995-08-05 | 1996-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-03 | 1999-08-05 | 2000-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-03 | 2003-08-05 | 2004-02-04 | $7700.00 | Window Closed / Lapsed |