US3808516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical loss-dependent thermal simulator circuit of an electrical operating means such as electric motors and transformers
Assignee: Rockwell Automation Switzerland GmbH
•
Filing: 1973-05-11
•
Granted: 1974-04-30
•
Expires: 1993-05-11
Abstract
Abstract An electrical loss-dependent thermal simulation or simulator circuit of an electrical operating device, the circuit incorporating at least two RC-elements, by means of the capacitors and resistors of which there are determined the thermal capacity of the operating means and its heat transfer resistance. The resistors of the RC-element are electrically connected together into a two-pole resistance network and by means of the charging operation of the capacitors there is simulated the heating behavior of the operating device. There is provided switch circuit which can be connected by a switch mechanism with the resistance network, such switch means increasing the virtual impedance of the resistance network, and further wherein the RC-elements can be switched, by actuating the switch mechanism, from a predetermined time-constant, with switched-off switch means, to a larger time-constant, with switched-on switch means, and vice versa.
Inventors
- 👤 M Hentschel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:30
CPC Classifications
H; H02; H02H; H02H6/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
127 words
An electrical loss dependent-thermal simulator circuit for an electrical operation means, comprising at least two RC-elements, by means of the capacitors and resistors of which it is possible to determine the thermal capacity of the operating means and the heat transfer resistance, the resistors of said RC-element being coupled together to provide a two-terminal resistance network, and wherein charging of the capacitors simulates the heating behavior of the operating means, switch means for increasing the virtual impedance of the resistance network, a switch mechanism for connectIng the switch means with said resistance network, and wherein said RC-elements, through actuation of said switch mechanism, can be switched from a certain time-constant with the switch means switched-off, to a greater time-constant with the switch means switched-on, and vice versa.
Claim 2
Dependent Claim
127 words
An electrical loss dependent-thermal simulator circuit for an electrical operation means, comprising at least two RC-elements, by means of the capacitors and resistors of which it is possible to determine the thermal capacity of the operating means and the heat transfer resistance, the resistors of said RC-element being coupled together to provide a two-terminal resistance network, and wherein charging of the capacitors simulates the heating behavior of the operating means, switch means for increasing the virtual impedance of the resistance network, a switch mechanism for connectIng the switch means with said resistance network, and wherein said RC-elements, through actuation of said switch mechanism, can be switched from a certain time-constant with the switch means switched-off, to a greater time-constant with the switch means switched-on, and vice versa.
Claim 3
Dependent Claim
44 words
The thermal simulator circuit as defined in claim 1, wherein said switch means includes negative resistance means for increasing the virtual impedance of the resistance network, said negative resistance means being connected in parallel with said resistance network by means of said switch mechanism.
Claim 4
Dependent Claim
101 words
The thermal simulator circuit as defined in claim 2, wherein said negative resistance means comprises an operational amplifier having a non-inverting input, an inverting input and an output, the non-inverting input of said operational amplifier being connected with a first terminal of the resistance network and via a resistor and through the agency of the switching path of the switching mechanism with the output of the operational amplifier, and the inverting input of the operational amplifier being connected via a resistor with the output of the operational amplifier and via a further resistor with the other terminal of the resistance network.
Claim 5
Dependent Claim
130 words
The thermal simulator circuit as defined in claim 1, wherein said switch means includes an impedance converter for increasing the virtual impedance of the resistance network, said impedance converter having an input coupled with a first terminal of the resistance network and with which there is connected the capacitor associated with the resistor of a first of said two RC-elements in order to obtain an output voltage which is proportional or equal to the charging voltage of the capacitor, a voltage divider for applying a fraction of the output voltage of the impedance converter to the other terminal of the resistance network, wherein the virtual increase in the impedance of the resistance network is determined by the partial ratio of the tapped-off voltage to the charging voltage of said capacitor.
Claim 6
Dependent Claim
91 words
The thermal simulator circuit as defined in claim 4, further including a voltage divider for applying at least for the first RC-element at the base point of its capacitor a fraction of the output voltage of the impedance converter, so that the capacitance of the capacitor of the first RC-element is correspondingly reduced virtually with regard to the partial ratio of the voltage divider, and by adjusting the partial ratio at the voltage divider connected with the capacitor of said first RC-element there can be changed the time-constant of such RC-element.
Claim 7
Dependent Claim
44 words
The thermal simulator circuit as defined in claim 1, further including an electronically controlled switch connected with one of said RC-elements, and wherein said one RC-element and the electronically controlled switch constitute a molded block to protect against leakage currents brought about by moisture.
Claim 8
Dependent Claim
49 words
The thermal simulator circuit as defined in claim 1, wherein the switch mechanism comprises a controllable electronic switch which is controlled by control signals indicating the momentary operating condition of the operating means for switching-on and switching-off the switch means fo increasing the virtual impedance of the resistance network.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-29 | 1977-10-29 | 1978-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-29 | 1981-10-29 | 1982-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-29 | 1985-10-29 | 1986-04-30 | $7700.00 | Window Closed / Lapsed |