US4194145A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for monitoring the run-up to speed of asynchronous motors and apparatus for the performance thereof
Assignee: BBC Brown Boveri AG Switzerland
•
Filing: 1978-02-10
•
Granted: 1980-03-18
•
Expires: 1998-02-10
Abstract
Abstract A method of, and apparatus for, monitoring the run-up to speed of asynchronous motors which are turned-off within a permissible blocking or cutoff time of the motor when the speed run-up is improper, wherein after turning-on the motor there is determined a first value of an electrical magnitude which is dependent upon the phase angle between the motor current and the motor voltage after expiration of a first time-delay following turning-on of the motor, and there is then determined a second value of said electrical magnitude after expiration of a second time-delay following the turning-on of the motor. Both the first and second values are compared with one another, and the motor is turned-off when, following such comparison, there is present a magnitude indicative of improper run-up to speed of the motor.
Inventors
- 👤 Franz Ritter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:42
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0816; H02H7/093
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
137 words
A method of monitoring the run-up to speed of asynchronous motors which are turned-off within a permissible blocking time of the motor when the speed run-up is improper, comprising the steps of: turning-on the monitored motor; determining a first electrical magnitude dependent upon the phase angle between the motor current and the motor voltage after expiration of a first time-delay following turning-on of the motor; determining a second value of said electrical magnitude which is dependent upon the phase angle between the motor current and the motor voltage after expiration of a second time-delay following turning-on of the motor; comparing both the first and second values with one another; and turning-off the motor when the comparison of the first and second values with one another produces a magnitude indicative of improper run-up to speed of the motor.
Claim 2
Independent Claim
137 words
A method of monitoring the run-up to speed of asynchronous motors which are turned-off within a permissible blocking time of the motor when the speed run-up is improper, comprising the steps of: turning-on the monitored motor; determining a first electrical magnitude dependent upon the phase angle between the motor current and the motor voltage after expiration of a first time-delay following turning-on of the motor; determining a second value of said electrical magnitude which is dependent upon the phase angle between the motor current and the motor voltage after expiration of a second time-delay following turning-on of the motor; comparing both the first and second values with one another; and turning-off the motor when the comparison of the first and second values with one another produces a magnitude indicative of improper run-up to speed of the motor.
Claim 3
Dependent Claim
54 words
The method as defined in claim 1, further including the steps of: selecting the first time-delay such that direct-current components whhich arise during turning-on of the motor have essentially decayed; and selecting the second time-delay to be greater than the first time-delay but at most equal to the permissible blocking time of the motor.
Claim 4
Dependent Claim
21 words
The method as defined in claim 3, wherein: the second time-delay is smaller than the permissible blocking time of the motor.
Claim 5
Dependent Claim
129 words
The method as defined in claim 1, further including the steps of: employing an electronic measuring device and electronic timing device operatively connected with the motor; setting the first and second time-delays at the electronic timing device; setting a rated motor current at the electronic measuring device; initiating the measuring operation after exceeding a predetermined current peak value; storing the first value of the phase angle-dependent magnitude which has been determined after the first time delay; determining after expiration of the second time-delay the second value of the phase angle-dependent magnitude; adding to the first value a safety margin-value; comparing the first value increased by the safety margin-value with the second value; and turning-off the motor when the first value increased by the safety margin-value exceeds the second value.
Claim 6
Dependent Claim
24 words
The method as defined in claim 1, further including the steps of: using as the phase angle-dependent magnitudes the effective resistance of the motor.
Claim 7
Dependent Claim
104 words
The method as defined in claim 5, further including the steps of: utilizing a transformer having a load connected to its output for obtaining a motor current signal; utilizing said load for adjusting the magnitude of said motor current signal to the rated current of the motor; performing a triggering operation to initiate the course of the first and second time-delays; measuring the current I . cos φ over a number of periods; determining in a divider the effective resistance of the motor during the first time-delay; and determining in the divider the effective resistance of the motor after expiration of the second time-delay.
Claim 8
Dependent Claim
29 words
The method as defined in claim 1, further including the steps of: employing as the phase angle-dependent magnitudes the phase angle itself between the motor current and motor voltage.
Claim 9
Dependent Claim
107 words
The method as defined in claim 7, further including the steps of: utilizing a transformer having a load connected to its output for obtaining a motor current signal; utilizing said load for adjusting the magnitude of said motor current signal to the rated current of the motor; employing a triggering operation to initiate the course of the first and second time-delay; determining the phase angle after expiration of the first time-delay by comparison of the phase of the motor current and the motor voltage; and determining the phase angle after expiration of the second time-delay by comparing the phase of the motor current and the motor voltage.
Claim 10
Dependent Claim
31 words
The method as defined in claim 1, further including the steps of: employing as the phase angle-dependent magnitude the cosine of the phase angle between the motor current and motor voltage.
Claim 11
Independent Claim
127 words
A method of monitoring the run-up to speed of asynchronous motors which are turned-off within a permissible blocking time of the motor when the speed run-up is improper, comprising the steps of: turning-on the monitored motor; forming a first electrical magnitude dependent upon the phase angle between the motor current and the motor voltage after expiration of a first time-delay following turning-on of the motor; forming a second value of said electrical magnitude which is dependent upon the phase angle between the motor current and the motor voltage after expiration of a second time-delay following turning-on of the motor; processing both said first and second values; and obtaining from the processing step a motor trigger signal for turning-off the motor when the motor improperly runs-up to speed.
Claim 12
Independent Claim
127 words
A method of monitoring the run-up to speed of asynchronous motors which are turned-off within a permissible blocking time of the motor when the speed run-up is improper, comprising the steps of: turning-on the monitored motor; forming a first electrical magnitude dependent upon the phase angle between the motor current and the motor voltage after expiration of a first time-delay following turning-on of the motor; forming a second value of said electrical magnitude which is dependent upon the phase angle between the motor current and the motor voltage after expiration of a second time-delay following turning-on of the motor; processing both said first and second values; and obtaining from the processing step a motor trigger signal for turning-off the motor when the motor improperly runs-up to speed.
Claim 13
Independent Claim
138 words
An apparatus for monitoring the run-up to speed of an asynchronous motor by detecting a rotational speed dependent-physical magnitude within a permissible blocking time of the motor, comprising: means for converting current and voltage signals delivered by the motor; means for initiating and determining the duration of the measurement of phase angle-dependent magnitudes of the monitored motor by forming a first value of an electrical magnitude dependent upon the phase angle between the motor current and motor voltage after expiration of a first time-delay following turning-on of the motor and by forming a second value of such phase angle-dependent magnitude after expiration of a second time-delay after the turning-on of the motor; means for determining the changes as a function of time of the phase angle-dependent magnitude; and means for delivering a trigger command for turning-off the motor.
Claim 14
Independent Claim
138 words
An apparatus for monitoring the run-up to speed of an asynchronous motor by detecting a rotational speed dependent-physical magnitude within a permissible blocking time of the motor, comprising: means for converting current and voltage signals delivered by the motor; means for initiating and determining the duration of the measurement of phase angle-dependent magnitudes of the monitored motor by forming a first value of an electrical magnitude dependent upon the phase angle between the motor current and motor voltage after expiration of a first time-delay following turning-on of the motor and by forming a second value of such phase angle-dependent magnitude after expiration of a second time-delay after the turning-on of the motor; means for determining the changes as a function of time of the phase angle-dependent magnitude; and means for delivering a trigger command for turning-off the motor.
Claim 15
Dependent Claim
77 words
The apparatus as defined in claim 11, wherein said means for initiating and determining the duration of the measurement of the phase angle-dependent magnitudes, comprises: a trigger circuit; pulse prolongation means cooperating with said trigger circuit; a monostable multivibrator; a first fixedly adjustable time-delay means for activating said monostable multivibrator after expiration of the fixedly adjustable first time-delay; a second fixedly adjustable time-delay means for activating said monostable multivibrator after expiration of a fixed settable second time-delay.
Claim 16
Dependent Claim
68 words
The apparatus as defined in claim 12, wherein said means for determining the change as a function of time of the phase angle-dependent magnitudes comprises: a storage for the recall of the first value determined after expiration of the first-delay; an adder for increasing the first value by a safety margin-value; and comparison means for comparing the first value increased by the safety margin-value with the second value.
Claim 17
Dependent Claim
119 words
The apparatus as defined in claim 11, wherein said means for converting the current and voltage signals delivered by the motor serves for the determination of effective resistances as phase angle-dependent magnitudes and comprises: an intermediate converter for producing a direct-current voltage substantially proportional to the motor voltage; a rectifier connected with said intermediate converter; a pulse converter connected with the intermediate converter for transforming a substantially sinusoidal motor voltage into a square wave signal of the same phase; a bipolar switch controlled by the square wave signal; a filter for producing a direct-current voltage proportional to the product I . cosine ρ; a load for accommodating the rated motor current; and a divider for forming the effective resistance.
Claim 18
Dependent Claim
124 words
The apparatus as defined in claim 11, wherein said means for converting the current and voltage signals delivered by the motor serves for the determination of the phase angle-dependent magnitudes in the form of phase angles and comprises: an intermediate converter for transforming an essentially sinusoidal motor voltage into a square wave signal of the same phase; a first pulse converter connected with said intermediate converter; a load for accommodating the rated motor current; a second pulse converter connected with the intermediate converter for transforming the signal accommodated at the load to the motor current into a square wave signal of the same phase; and a filter for determining the phase angle between signals which are proportional to the motor current and motor voltage.
References Cited (Backward Citations)
US2992365A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-03-18 | 1983-09-17 | 1984-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-18 | 1987-09-17 | 1988-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-18 | 1991-09-17 | 1992-03-18 | $7700.00 | Window Closed / Lapsed |