Patent US3821623A successfully refreshed from Google Patents.
US3821623A
Expired / Lapsed
US
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Means for detecting operation of servosystem
Assignee: Fujifilm Holdings Corp
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Filing: 1973-01-19
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Granted: 1974-06-28
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Expires: 1993-01-19
Abstract
Abstract Increase and descrease of the current flowing through a field coil of a servomotor is detected, and the signal of the detection is used as an output for indicating whether the servosystem is in operation or not.
Inventors
- 👤 M Inuiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:00
CPC Classifications
G; G05; G05D; G05D3/00; G05D3/12; G05D3/14; G05D3/18; G05D3/183
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
130 words
A method of detecting whether a servomotor system is operating, wherein the servosystem includes a first servomotor comprising an armature winding, means for applying A.C. power to said armature winding, a center-tapped field winding, means for applying an A.C. control signal across the ends of the field winding, the method comprising the steps of: a. detecting the level of only D.C. field current flowing through the center tap of the field winding, b. comparing the detected current level with a threshold current level which defines the boundary between operation and nonoperation of the servomotor, and c. producing a first signal indicative of servomotor operation when the detected level is above the threshold level and a second signal indicative of servomotor non-operation when the detected level is below the threshold level.
Claim 2
Independent Claim
130 words
A method of detecting whether a servomotor system is operating, wherein the servosystem includes a first servomotor comprising an armature winding, means for applying A.C. power to said armature winding, a center-tapped field winding, means for applying an A.C. control signal across the ends of the field winding, the method comprising the steps of: a. detecting the level of only D.C. field current flowing through the center tap of the field winding, b. comparing the detected current level with a threshold current level which defines the boundary between operation and nonoperation of the servomotor, and c. producing a first signal indicative of servomotor operation when the detected level is above the threshold level and a second signal indicative of servomotor non-operation when the detected level is below the threshold level.
Claim 3
Dependent Claim
50 words
A method as defined in claim 1 wherein the servosystem includes a second servomotor identical to the first servomotor and wherein the two center taps are connected in parallel, and wherein the detecting step further comprises detecting the level of the total D.C. field current flowing through both center taps.
Claim 4
Dependent Claim
133 words
In a servosystem including a servosystem having a first servomotor comprising an armature winding, means for applying A.C. power to the armature winding, a center-tapped field coil, means for applying an A.C. control signal across the ends of the field coil, and a servomotor field power source for applying D.C. power to the center tap, the improvement which comprises: a. means for detecting the level of only D.C. field current flowing through the center tap of the field coil; b. means coupled to said detecting means for comparing the detected field current level with a threshold current level and producing a first signal indicative of servomotor operation when the detected level is above the threshold level and a second signal indicative of servomotor non-operation when the detected level is below the threshold level.
Claim 5
Dependent Claim
133 words
In a servosystem including a servosystem having a first servomotor comprising an armature winding, means for applying A.C. power to the armature winding, a center-tapped field coil, means for applying an A.C. control signal across the ends of the field coil, and a servomotor field power source for applying D.C. power to the center tap, the improvement which comprises: a. means for detecting the level of only D.C. field current flowing through the center tap of the field coil; b. means coupled to said detecting means for comparing the detected field current level with a threshold current level and producing a first signal indicative of servomotor operation when the detected level is above the threshold level and a second signal indicative of servomotor non-operation when the detected level is below the threshold level.
Claim 6
Dependent Claim
17 words
The improvement defined in claim 3 comprising a low-pass filter coupled between said detecting and comparing means.
Claim 7
Dependent Claim
23 words
The improvement defined in claim 4 further comprising a relay coupled to said comparing means and operated by said first and second signals.
Claim 8
Dependent Claim
55 words
The improvement defined in claim 3 wherein the servosystem includes a second servomotor identical to the first, and means connecting the two center taps in parallel, and wherein said detecting means comprises a resistor connected in series with the two parallel-connected center taps for detecting the total D.C. field current flowing to both center taps.
Claim 9
Dependent Claim
29 words
The improvement defined in claim 3 wherein said detecting means comprises a resistor connected in series between the field coil of the servomotor and the servomotor field power source.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |