DE419774C - Voltage independent ohmmeter for alternating current - Google Patents
Voltage independent ohmmeter for alternating currentInfo
- Publication number
- DE419774C DE419774C DEH99205D DEH0099205D DE419774C DE 419774 C DE419774 C DE 419774C DE H99205 D DEH99205 D DE H99205D DE H0099205 D DEH0099205 D DE H0099205D DE 419774 C DE419774 C DE 419774C
- Authority
- DE
- Germany
- Prior art keywords
- coil
- ohmmeter
- alternating current
- voltage independent
- arrangement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Magnetic Variables (AREA)
Description
Von. Wechselstrom-Ohmmetern sind bisher hauptsächlich zwei Anordnungen zur Anwendung gelangt, die als spannungsunabhängig anzusprechen sind.From. AC ohmmeters are so far mainly two arrangements are used, which are independent of the voltage are to be addressed.
i. Kreuzspulinstrumente ohne mechanische Richtkraft mit von Wechselstrom erregten Feldmagneten. Die Richtkraft wird hauptsächlich durch die Inhomogenität des Felles bedingt. Die Anordnung ist aus Abb. ι zu ίο ersehen. Es bedeuten F die Feldspule, K die Kreuzspule, Rv den Vergleichswiderstand, Rx den zu messenden Widerstand.i. Cross-coil instruments without mechanical straightening force with field magnets excited by alternating current. The straightening force is mainly due to the inhomogeneity of the skin. The arrangement can be seen from Fig. Ι zu ίο. F is the field coil, K is the cross coil, R v is the comparison resistance, R x is the resistance to be measured.
2. Eisengeschlossene Elektrodynamometer ohne mechanische Richtkraft, deren Drehspule im Nullzweig einer Brückenanordnung liegt. Die Richtkraft liefert der in der Drehspuk durch das Wechselfeld induzierte Strom. Die Anordnung ist in Abb. 2 dargestellt. Es bedeuten F die Feldspule, D die Drehspule, Rv den Vergleichswiderstand, Rx den zu messenden Widerstand.2. Iron-closed electrodynamometers without mechanical straightening force, the moving coil of which is in the zero branch of a bridge arrangement. The directional force is supplied by the current induced in the rotating spook by the alternating field. The arrangement is shown in Fig. 2. F denotes the field coil, D the moving coil, R v the comparison resistance, R x the resistance to be measured.
Ein Nachteil der Anordnung 1 ist der verhältnismäßig geringe Ausschlagswinkel.A disadvantage of the arrangement 1 is that it is proportionate low deflection angle.
Ein Nachteil der Anordnung 2 ist der, daß man den zu messenden Widerstand verhältnismäßig stark belasten muß, um genügend starke Ströme im Nullzweig der Brücke zu erhalten. In gewissen Fällen, wo hoheA disadvantage of the arrangement 2 is that the resistance to be measured is proportionate must load heavily in order to obtain sufficiently strong currents in the neutral branch of the bridge. In certain cases where high
Empfindlichkeit verlangt ist, erschwert dieser Umstand sehr die Verwendung der Anordnung 2.Sensitivity is required, this circumstance makes it very difficult to use the arrangement 2.
Die Erfindung betrifft ein instrument und eine Anordnung, welche in einfacher Weise die beiden Nachteile vermeidet. Die Anordnung ist aus Abb. 3 zu ersehen. Das Instrument besteht aus einem Elektrodynamometer, dessen bewegliche Spule zwei gleicheThe invention relates to an instrument and an arrangement which avoids the two disadvantages in a simple manner. The order can be seen from Fig. 3. The instrument consists of an electrodynamometer, whose moving coil is two of the same
to Wicklungen S1 und S2 enthält, welche so geschaltet sind, daß beide von dem durch die äußere Stromquelle unmittelbar erzeugten Strom in entgegengesetzter Richtung durchflossen werden. Der durch das Wechselfeld der Spule F erzeugte Induktionsstrom dagegen durchfließt die Spulen S1 und S2 in der gleichen Richtung und ergibt deshalb ein Richtmoment, dessen Nullage sich in der Symmetriestellung der Spule befindet, in welcher diese parallel zu dem Induktionsfluß liegt. Je nach dem Überwiegen des Stromes in der Wicklung S1 oder S2, entsprechend dem größeren oder kleineren Wert des zu messenden Widerstandes Rx, erfolgt deshalb ein diesem größeren Unterschied nahezu proportionaler Ausschlag der Spule nach der einen oder anderen Seite. Um Phasengleichheit des Magnetwechselfeldes und der Meßströme in den Spulen zu erzielen, empfiehlt es sich, Magnetwicklung und Spulenzweige, letztere in Parallelschaltung, hintereinanderzuschalten. Um die Meßströme in den Spulen und den Feldstrom unabhängig voneinander wählen zu können, ist es zweckmäßig, in beiden Spulenzweigen einen Widerstand Rn (Abb. 3) parallel zu schalten.to windings S 1 and S 2 , which are connected so that the current directly generated by the external power source flows through both in opposite directions. The induction current generated by the alternating field of the coil F , on the other hand, flows through the coils S 1 and S 2 in the same direction and therefore results in a directional moment whose zero position is in the symmetrical position of the coil, in which it is parallel to the induction flux. Depending on the predominance of the current in the winding S 1 or S 2 , corresponding to the larger or smaller value of the resistance R x to be measured, there is therefore a deflection of the coil to one side or the other that is almost proportional to this larger difference. In order to achieve phase equality of the alternating magnetic field and the measuring currents in the coils, it is advisable to connect the magnet winding and coil branches, the latter in parallel, one behind the other. In order to be able to select the measuring currents in the coils and the field current independently of one another, it is advisable to connect a resistor R n (Fig. 3) in parallel in both coil branches.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEH99205D DE419774C (en) | 1924-11-12 | 1924-11-12 | Voltage independent ohmmeter for alternating current |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEH99205D DE419774C (en) | 1924-11-12 | 1924-11-12 | Voltage independent ohmmeter for alternating current |
Publications (1)
Publication Number | Publication Date |
---|---|
DE419774C true DE419774C (en) | 1925-10-10 |
Family
ID=7168261
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DEH99205D Expired DE419774C (en) | 1924-11-12 | 1924-11-12 | Voltage independent ohmmeter for alternating current |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE419774C (en) |
-
1924
- 1924-11-12 DE DEH99205D patent/DE419774C/en not_active Expired
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