CN85102463A - Motor load detects and the overload protection method and apparatus - Google Patents
Motor load detects and the overload protection method and apparatus Download PDFInfo
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- CN85102463A CN85102463A CN85102463.7A CN85102463A CN85102463A CN 85102463 A CN85102463 A CN 85102463A CN 85102463 A CN85102463 A CN 85102463A CN 85102463 A CN85102463 A CN 85102463A
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Abstract
Motor load detect with the overload protection method and apparatus be analog motor windings temperature method for detecting and device.This method, is simulated and is detected winding temperature by the equivalent relation between the two and the superposition principle of heat effect by detecting dynamically thermal resistance of motor equivalence thermal power, the equivalence of simulated machine winding, also is " thermal power～equivalent thermal resistance method ".This device input electrical detection running current, working voltage, ambient temperature, cooling condition provide the voltage of direct proportion in the motor windings temperature at output, are used for motor load and detect and the motor overload protection.
Description
Motor load detects and the overload protection method and apparatus
The invention belongs to analog motor windings temperature method for detecting and device.Be used for motor load indication and overload protection.
General analog motor windings temperature method for detecting is " electric current-limited time expander method ".Their representative device is that the overload of motor (transformer, electric rotating machine) detects and overload protection device.This device detects the running current (I) of motor, and when running current reached setting, the time that the winding temperature rising reaches permissible value was expressed in the deferred action of stipulating.Further have to detect electric current handle after time-delay, as square (I of power taking stream
2), overload electric current and load current comparison value, load current and overload electric current detect respectively etc.It then be the time integral of current squaring that time-delay simulation temperature rise is increased, and fragment delay, delays time by the different heat position; Duration curve adopts exponential curve, straight line, two exponential curve actions respectively, modified exponential curve and integral controllers (1/ (S)) and inertia governor ((K)/(1+S τ
2)) the analog circuit etc. that links.Because motor operating current is not the unique factor that causes the motor windings heating up, be the complex curve relevant with load owing to the winding temperature growth rate again with the thermal characteristics of winding, thereby " electric current-limited time expander method " and the weak point of having improved one's methods thereof.
The objective of the invention is to improve the ability of simulation electrical detection winding temperature, to follow the motor windings temperature, particularly in the motor load Operational Zone and the overload district follow the ability of temperature instantaneous value, carry out that motor load detects and overload protection.
Content of the present invention is that the motor load that has proposed " thermal power-dynamic heat resistance method " detects and the overload protection method and apparatus." thermal power-dynamic heat resistance method " is by detecting the equivalent thermal power of motor; the equivalence of simulated machine winding is thermal resistance dynamically; by equivalent thermal power and the equivalent relation of the dynamic thermal resistance of equivalence and the superposition principle of heat effect; carry out the motor windings temperature simulation and detect method with overload protection, and motor windings temperature simulation according to said method detects and overload protection device.
The temperature of motor windings mean temperature and winding specified point is different, and simulation detects equivalent thermal power and the dynamic thermal resistance of equivalence that should get separately, below is referred to as dynamically thermal resistance of motor equivalence thermal power and equivalence.
The explanation of motor equivalence thermal power: motor equivalence thermal power is partly formed promptly equivalent copper loss power, equivalent iron loss power, equivalent environment thermal power by three.The equivalence thermal power is the thermal source that causes the motor windings heating up, is the equivalent thermal power that the inside and outside thermal power of motor causes heating in winding to heat up.Wherein equivalent copper loss power is the loss heat that occurs in the motor windings, is the m power (I of motor operating current I according to it
m) concern equivalence with motor windings resistance multiplies each other, change because motor windings resistance is temperature with winding, thereby equivalent copper loss power not only changes with the variation of electric current, also change equivalent coefficient m 〉=1 with the motor windings changes in resistance; Equivalence iron loss power is the loss heat that occurs in the electric machine iron core, is the n power equivalence (K of motor working voltage U according to it
1U
n), equivalent iron loss power changes with the variation of voltage, equivalent coefficient n 〉=1, K
1＞0; Equivalence environment thermal power is the equivalent thermal power of ambient temperature to motor windings temperature effect, is linear relationship equivalence (K according to it and ambient temperature
2T
0), equivalent environment thermal power changes with variation of ambient temperature, equivalent coefficient K
2＞0.The equivalence thermal power is to obtain by running current, working voltage and the ambient temperature that detects motor.
The dynamically explanation of thermal resistance of motor equivalence: motor equivalence dynamically thermal resistance (curve) is that motor windings is under the effect of unit equivalence thermal power, the time dependent rate curve of temperature, it is the actual reflection of winding temperature increasing law, the equivalence thermal power is a watt-hour (W), equivalence dynamically thermal resistance curve is (℃/W-t(S)), it is the curve of a complexity, finally reaches stationary value (definition of stationary value is same as the definition of motor temperature-raising experiment).The dynamic thermal resistance of average equivalence of motor windings and each specified point be inequality, use the temperature rise curve of temperature rise test corresponding specified point or average, under unit equivalence thermal power effect, the winding temperature curve of growth rate is in time obtained dynamically thermal resistance curve of equivalence respectively.Reappear in the circuit of this relation in the dynamic thermal resistance curve of analog equivalent, according to the different needs and the requirement of precision, adopt the method for this curve of direct modeling, and the method simulation of adopting other, as: according to time constant by the curve of a little numerical value to a big numerical value continuous transition; According to a little step is arranged when initial, time constant is by the curve of a little numerical value to a big numerical value continuous transition, these analogy methods have reflected that motor winding temperature rise speed in the different time, has the characteristic of speed inequality, and stationary value is all arranged.Also can be by single index curve and straight line simulation (straight line no longer increases after reaching maximum).Concrete circuit illustrates in circuit description.When the cooling condition of motor changes, for example forced air-cooled motor blowing-out, motor equivalence dynamically thermal resistance has very big change; The equivalence of self-cooled machine dry run cooling dynamically thermal resistance also is that big difference is arranged, and detects and adjust the shape of the dynamic thermal resistance of analog equivalent by the terminal of cooling condition.
Method of the present invention according to equivalent thermal power and equivalence dynamically the superposition principle of the equivalent relation of thermal resistance and heat effect try to achieve transitive relation between each parameter.Fig. 1 is a dynamically thermal resistance curve of a kind of squirrel-cage motor equivalence, and the equivalent thermal power of establishing motor remains unchanged, and the motor windings temperature will be parallel to dynamically thermal resistance line rising of equivalence, finally reach stationary value.When asking t
1Temperature T constantly
1The time, then to get t
1Equivalence constantly is thermal resistance R dynamically
d(t
1), their relationship between expression formula is T(t)=PR
d(t), in the formula T be the motor windings temperature (℃); P is equivalent thermal power (W); R
d(t) be equivalence dynamically thermal resistance (℃/W), it is the function of time, but under the condition of reality, the equivalent thermal power of motor changes, at this moment just press the superposition principle of heat effect, promptly at a time the temperature T of t (t) is the superposition that constantly former all hotworks of t are used for the winding result, thereby T(t)=
Express equivalent thermal power in the Laplace territory, equivalence is thermal resistance dynamically, and the relation of simulation winding temperature is exactly P(S) → R
d(S) → T(S).
The invention has the advantages that and detected the heat that causes the motor windings heating up; According to the real warming law that has, it also is dynamic thermal resistance, and expressed the thermal conduction characteristic between winding temperature and heat and the coolant and the complex relationship of heat-sinking capability with equivalent relation, and the accumulation effect of heat effect, thereby the simulation that improves winding temperature detects ability and follows effect; Action as overload protection is a benchmark with the winding allowable temperature; and the no standard time limit; for cold conditions overcurrent, hot overcurrent; and frequent repeatedly overcurrent is an operation condition with the winding temperature permissible value all; be operation condition promptly also, brought into play the motor ability and improved action sensitivity with the overload.
Method of the present invention is at the heating in winding in the electrical equipment machine, thereby other electrical equipment such as reactor, the circuit etc. that are applicable to electric rotating machine, transformer and coil is arranged.For its operational parameter detection method difference of alternating current-direct current electrical equipment (for example alternating current detect Current Transformer), other is identical; This device has the effect of motor thermal model.
All be normalized for the simulation of the dynamic thermal resistance of equivalence and the conversion of equivalent thermal power in the method and apparatus of the present invention, its function also can be carried out in microcomputer.
The description of the drawings:
Rd(t among Fig. 1) be dynamically thermal resistance curve of equivalence, when equivalent thermal power is constant.The winding temperature curve will be parallel to dynamically thermal resistance curve of equivalence.Fig. 2 is that motor load detects and the overload protection device circuit theory diagrams CT: current transformer, the electrical detection running current also becomes the voltage U of direct proportion in running current through the I circuit
1; PT: voltage transformer, the electrical detection working voltage also becomes the voltage U of direct proportion in working voltage through the U circuit
2; AT: environment temperature sensor, electrical detection ambient temperature and through T
0Circuit becomes the voltage U of direct proportion in ambient temperature
3; The P circuit is equivalent thermal power translation circuit, and corresponding each input parameter is transformed to equivalent thermal power as stated above; R
dCircuit is a dynamically thermal resistance element circuit of equivalence, simulates by the dynamic thermal resistance curve of equivalence, and K is a motor cooling condition detecting circuit, is connected to R
dCircuit is to change the dynamically parameter of thermal resistance unit of equivalence; Output to the binding of P circuit is to be the feedback circuit of the functional relation requirement of winding temperature according to equivalent copper loss; Working voltage is also controlled the dynamically variation of parameter of thermal resistance unit of equivalence.
Fig. 3 is a circuit diagram for example of implementing apparatus of the present invention.It is the device internal circuit that carries out according to method of the present invention, is loaded in the shell of sealing, is connected by detection terminal and lead-out terminal and outside, and the dress system of circuit is pressed Fig. 3 Fig. 4 and the following description:
The 1-A of the 1st circuit is motor operating current testing circuit and level adjustment circuit, and current transformer CT electrical detection running current is through rectifying and wave-filtering and level adjustment unit A
1, provide the voltage U of direct proportion in motor operating current at the 1-1 point
1, the level adjustment unit is for the voltage of difference input being transferred to the level of a circuit requirement, level adjustment circuit that also can be otherwise, and the 1-B of the 1st circuit is equivalent copper loss power conversion circuit; When the 1-1 point is the voltage U of direct proportion in motor operating current
1, the output voltage (U of ordering at 1-4
4) with direct proportion in equivalent copper loss power.The function of each assembly of circuit has been annotated in the drawings: the input and output equivalent coefficient m of the m power function generator of B-1, adjust according to equivalent copper loss power characteristic; B-3 is the motor windings resistance generator, and it provides the aanalogvoltage U that is proportional to winding resistance at output
r, because U
rBe the function of motor windings temperature, be connected with output circuit 5 by the 1-5 point that B-2 is a multiplier, its output voltage is equivalent copper loss voltage, and having expressed equivalent copper loss power is I
mThe relation that multiplies each other with motor windings resistance.
The 2nd circuit is that the motor working voltage detects and be transformed to equivalent iron loss power conversion circuit.Voltage transformer pt electrical detection working voltage provides the voltage U of direct proportion in the motor working voltage at the 2-1 point
2, U
2Be transformed to K through n power function generator
1U
n 2, also promptly be transformed to the voltage U of direct proportion in equivalent iron loss power
5, equivalent coefficient n adjusts according to equivalent iron loss power characteristic.
The 3rd circuit is circuit and the cooling condition testing circuit that the motor ambient temperature detected and be transformed to equivalent environment thermal power.Environment temperature sensor AT electrical detection ambient temperature and through level adjusting circuit D-1 linear amplification provides the voltage U of direct proportion in equivalent environment thermal power at the 3-1 point
6; When environmental temperature fluctuation is little, also can not use AT, use aanalogvoltage U and connect
6The D-2 switching circuit is controlled by cooling condition and changes, and for example the cooling air blowing-out will produce very big change to the parameter of electric machine, adjusts parameter by D-2.
The 4th circuit is a dynamically thermal resistance element circuit of equivalence, is connected equivalent thermal power translation circuit and is exported direct proportion in the voltage of motor windings temperature through summing circuit by it.Equivalence dynamically thermal resistance curve has reflected the characteristic of motor winding temperature rise, and for example when giving to load, the winding programming rate is very fast, slows down later on and reaches stable state.Among the present invention to the analogy method of thermal resistance curve as above-mentioned.The dynamic thermal resistance analogue unit of concrete equivalence in the 4th circuit can require to adopt as the 4th figure according to difference; (transitive relation is 1/ (S) * (Rd to Fig. 4-1 by a first order inertial loop adjuster
1)/(S+ τ
1)) have proportion differential adjuster (1/ (S) * (S+ τ of inertia with another
3)/(S+ τ
2) Rd
2) and time constant adjusting device form, its output between relation (1/ (S) ((Rd)/(S+ τ
1)+Rd
2(S+ τ
3)/(S+ τ
2))), function curve is annotated in figure, the timeconstant among the figure
1, τ
2, τ
3, and Rd
1, Rd
2Determine as requested and adjustment that Fig. 4-2 is made up of two first order inertial loop adjusters and time constant adjusting device thereof, the composition of its relation is 1/ (S) ((Rd
1)/(S+ τ
1)+(Rd
2)/(S+ τ
2)).Fig. 4-1; the circuit of 4-2 is except using as the dynamic thermal resistance curve element circuit of equivalence of the present invention; follow requirement owing to reflected relation with different growth rate and general time-delay; also be applicable to delay circuits such as general temperature rise, load; the delay circuit of overload relaying protection for example, the delay circuit design of electric current-time principle.
Formed motor windings temperature detecting circuit by above circuit and accessory circuit (power supply circuits, summing circuit etc.), promptly motor load detects the device with overload protecting circuit.
4. after the preceding revisal of the capable revisal of file name page or leaf
Specification 1 12 (1/ (S)) (1/ (S τ
1))
The 3 22 equivalences dynamically dynamic thermal resistance curve of thermal resistance line rising equivalence are risen,
69 equivalent coefficient n according to etc. equivalent coefficient n, K
1According to etc.
6 18 circuit and through the summing circuit output circuit and in the output circuit 5
Summing circuit A
5Output
6 21 ... as the 4th figure, can be according to difference ... as above-mentioned motor equivalence dynamically
22 require to adopt; In the explanation of thermal resistance, when wherein needing
What adopt is according to when initial
A little step is arranged, and the time is normal
Count by a little numerical value to one
Big numerical value continuous transition curve,
With little by one according to time constant
Numerical value connect to a big numerical value
The curve of continuous transition is as among the 4th figure
4-1 and 4-2;
Pass therebetween, pass between 71 its outputs
Claims (9)
1, a kind of motor load of simulated machine winding temperature detects and the overload protection method.It is characterized in that by detecting the equivalent thermal power of motor; the equivalence of simulated machine is thermal resistance dynamically; by equivalent thermal power and the equivalent relation of the dynamic thermal resistance of equivalence and the superposition principle of heat effect; carry out the motor windings temperature simulation and detect method with overload protection, be i.e. " thermal power-dynamically heat resistance method ".
2, a kind of motor load that is exclusively used in claim 1 detects and overload protection device, it is characterized in that inside is equipped with the analog circuit board that detects that usefulness " thermal power-dynamically heat resistance method " makes; The input terminal of device detects and the relevant operational factor of motor equivalence thermal power, i.e. running current, working voltage, ambient temperature; In the voltage of motor windings temperature, be used for motor load indication, control and overload protection by a lead-out terminal output direct proportion.
3, according to the described detection motor of claim 1 equivalence thermal power, it is characterized in that detecting translation circuit by equivalent thermal power, detect as follows and conversion, i.e. the running current I of electrical detection is according to the equivalent copper loss power m power (I that is running current I
m) relation transformation that multiplies each other with motor windings resistance r is equivalent copper loss power P
Cu(resistance of motor windings with the motor windings variations in temperature, m 〉=1); Electrical detection working voltage U is according to the equivalent iron loss power n power (K that is working voltage
1U
n) relation transformation be equivalent iron loss power P
Fe; Electrical detection ambient temperature T
0, according to equivalent environment thermal power be and the directly proportional relation (K of ambient temperature
2T
0) be transformed to equivalent environment thermal power PT
0(K
1＞0, K
2＞0, n 〉=1).Motor equivalence thermal power is that above three kinds of equivalent thermal powers are formed.
4, according to the dynamic thermal resistance of the equivalence of claim 1 simulated machine winding, it is characterized in that according under the unit equivalence thermal power effect, winding temperature in time the curve of pace of change as the dynamic thermal resistance curve (unit equivalence thermal power is got W, and equivalence dynamically thermal resistance curve is C/W-t(s) of the equivalence of this motor.Average dynamic thermal resistance and each specified point of motor windings are inequality.) simulate according to six kinds of curves as required for the analogy method of so dynamic thermal resistance curve of equivalence, i.e. (1) direct modeling equivalence is thermal resistance curve dynamically; (2) according to time constant by the curve of a little numerical value to a big numerical value continuous transition; (3) according to a little step, time constant are arranged when initial by the curve of a little numerical value to a big numerical value continuous transition; (4) according to modified exponential curve; (5) according to the exponential curve that a time constant is arranged; (6) curve of linear growth.More than six kinds of curves increase along the time and all finally reach stationary value.Use dynamically thermal resistance element circuit simulation of equivalence.
5, according to claim 1 claim 3 claim 4 described " thermal power-dynamic heat resistance method ", it is characterized in that the output that equivalent thermal power is detected translation circuit is connected with the input of the dynamic thermal resistance element circuit of equivalence, when the output voltage that detects translation circuit when equivalent thermal power is equivalent to unit equivalence thermal power (W), output at the dynamic thermal resistance element circuit of equivalence will provide the voltage of direct proportion in the dynamic thermal resistance of equivalence, this voltage direct proportion is under the effect of unit equivalence thermal power, the temperature curve of motor windings.In " thermal power-dynamic heat resistance method ", equivalent thermal power P, equivalence be thermal resistance R dynamically
d, simulation detects transitive relation between the temperature T according to P(s) → R
d(S) → T(S).
6, according to claim 2, claim 3, the described device of claim 4 is characterized in that being equipped with in device inside the analog circuit board that detects that usefulness " thermal power-dynamically heat resistance method " makes, circuit by four circuit partly and accessory circuit form.
First circuit is the circuit that detects motor operating current and be transformed to equivalent copper loss power.With detect the m power (I that voltage according to equivalent copper loss power be running current I of direct proportion in running current I
m) relation that multiplies each other with motor windings resistance, be transformed to equivalent copper loss power voltage.The m of m power function generator is adjustable (m 〉=1); Motor windings resistance generator simulation winding resistance, its terminal is connected with the lead-out terminal of the direct ratio example winding temperature of this device, this feedback circuit according to the resistance direct proportion in Temperature Feedback.The input terminal voltage direct proportion of first circuit is in running current, and the output end voltage direct proportion is in equivalent copper loss power.
Second circuit is the circuit that detects the motor working voltage and be transformed to equivalent iron loss power.With detect the n power (K that voltage according to equivalent iron loss power be working voltage of direct proportion in working voltage U
1U
n) relation transformation be equivalent iron loss power voltage.The n of n power function generator is adjustable (n 〉=1).The input terminal voltage direct proportion of second circuit is in working voltage, and the output end voltage direct proportion is in equivalent iron loss power.
Tertiary circuit detects the motor ambient temperature and is transformed to the circuit of equivalent environment thermal power.With direct proportion in ambient temperature T
0The voltage that detects according to equivalent environment thermal power be and the directly proportional relation (K of ambient temperature
2T
0) be transformed to equivalent environment thermal power voltage.The input terminal voltage direct proportion of tertiary circuit is in ambient temperature, and the output end voltage direct proportion is in equivalent environment thermal power.Or directly with this thermal power of adjustable voltage equivalence.
The 4th circuit is a dynamically thermal resistance element circuit of equivalence, the dynamic thermal resistance curve of its analog equivalent.Circuit according to the described six kinds of curve methods foundation of claim 4.The input terminal voltage direct proportion of the 4th circuit is when unit equivalence thermal power, and the output end voltage direct proportion is in the dynamic thermal resistance curve of the equivalence that simulated.
By above circuit and accessory circuit (cooling condition variation detecting circuit; Running current, working voltage, ambient temperature detecting element; Summing circuit) the motor windings temperature detecting circuit of Zu Chenging, promptly motor load detects and overload protecting circuit.
7,, it is characterized in that with the dynamic dynamic thermal resistance curve of thermal resistance element circuit analog equivalent of equivalence according to the dynamic thermal resistance of the equivalence of claim 4 simulated machine.When wherein need to adopt be (2) in the claim 4 and (3) two kinds of curve simulations the time, adopt two kinds of following circuit:
First kind of circuit formed by two first order inertial loop adjusters and with the circuit that the time constant adjusting device connects mutually, and its transitive relation is 1/ (S) ((Rd
1)/(S+ τ
1)+(Rd
2)/(S+ τ
2)).Adjusting range is to decide according to the dynamic thermal resistance curve of the analog equivalent that is adopted.
Second kind of circuit is by a first order inertial loop adjuster (transitive relation 1/ (S) * (Rd
1)/(S+ τ
1)) and a proportion differential adjuster (transitive relation 1/ (S) * (S+ τ that has inertia
3)/(S+ τ
2) Rd
2) two circuit, and form with the circuit that the time constant adjusting device connects mutually.Input and output transitive relation 1/ (S) ((Rd of this circuit that two adjusters are formed
1)/(S+ τ
1)+Rd
2(S+ τ
3)/(S+ τ
2)).Each parameter of second kind of circuit is adjusted respectively, and its adjusting range is to decide according to the dynamic thermal resistance curve of the analog equivalent that is adopted.
Two kinds of circuit also are used for the delay circuit of overload relaying protection, the delay circuit of electric current-time principle.
8, according to the described method and apparatus of claim 1 claim 2, it is characterized in that between the input and output terminal of device, can connecting microcomputer and corresponding accessory circuit is finished the illustrated function of the inventive method promptly equivalent thermal power conversion and the dynamically simulation of thermal resistance of equivalence.Its circuit is connected to detection function circuit and parts-A/D converter-microcomputer-output circuit.P(S is pressed in the inside of microcomputer) → Rd(S) → T(S).
9, in accordance with the method for claim 2 and device, it is characterized in that the inventive method and device are applicable to motor (electric rotating machine, transformer) and are similar to electric equipment motor, that coil is arranged (for example reactor etc.) and circuit and electrothermal device; Alternating current machine in the electric rotating machine and the electric current of direct current machine, that voltage detects mode is different.Method and apparatus of the present invention is as motor thermal model
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85102463 CN1010068B (en) | 1985-04-01 | 1985-04-01 | Method and device for detecting load of motor and protecting motor from overload |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85102463 CN1010068B (en) | 1985-04-01 | 1985-04-01 | Method and device for detecting load of motor and protecting motor from overload |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85102463A true CN85102463A (en) | 1987-02-04 |
| CN1010068B CN1010068B (en) | 1990-10-17 |
Family
ID=4792532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 85102463 Expired CN1010068B (en) | 1985-04-01 | 1985-04-01 | Method and device for detecting load of motor and protecting motor from overload |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1010068B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100341221C (en) * | 2003-11-27 | 2007-10-03 | 南京南瑞继保电气有限公司 | Harmonic overload protecting method for reactor |
| CN103201922A (en) * | 2010-11-12 | 2013-07-10 | 施耐德电气美国股份有限公司 | Thermal memory in a fault powered system |
| WO2022043013A1 (en) * | 2020-08-31 | 2022-03-03 | Siemens Aktiengesellschaft | Method for monitoring a coil temperature |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5160834B2 (en) * | 2007-08-08 | 2013-03-13 | 株式会社島精機製作所 | Control device for carriage driving motor of flat knitting machine |
-
1985
- 1985-04-01 CN CN 85102463 patent/CN1010068B/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100341221C (en) * | 2003-11-27 | 2007-10-03 | 南京南瑞继保电气有限公司 | Harmonic overload protecting method for reactor |
| CN103201922A (en) * | 2010-11-12 | 2013-07-10 | 施耐德电气美国股份有限公司 | Thermal memory in a fault powered system |
| CN103201922B (en) * | 2010-11-12 | 2016-05-04 | 施耐德电气美国股份有限公司 | For the protection of the breaker of load |
| WO2022043013A1 (en) * | 2020-08-31 | 2022-03-03 | Siemens Aktiengesellschaft | Method for monitoring a coil temperature |
| US11898917B2 (en) | 2020-08-31 | 2024-02-13 | Siemens Aktiengesellschaft | Method for monitoring a coil temperature |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1010068B (en) | 1990-10-17 |
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