Precision measuring bridge for high and low voltage according to Schering
Features
General
2801
Measurement ranges
– Standard measurem measurements with with direct direct dissidissi- Th The Scherin ring AC me measu asurin ring bri bridg dge e is used tan δ : 0...3.5 (350 %) and more pation factor reading up to tan δ = for capacitance and dielectric loss mea- CX with CN ~ 100 pF: 1.111. surements of all sorts of capacitors, such as direct: 0 pF...11 µF – Special measu measurem rement ents for low dissipation cables, solid and liquid insulants, etc. with external shunt, type 2902: factors. Due to a special circuit arrange- Measurements are possible at operating up to 110 µF ment, tan δ is 0.01·C4 (C4 in µF) for all voltage and operating frequency. with current transformer, type adjustable fixed resistors R4 between Standard calibration: 50 or 60 Hz. 4732–4761: up to 10 000 µF 100 and 10 000 ohm. – Measurem easurements with direct capacitance Design features and Measurement accuracy reading. Capacitance: ± 0.04 % technical specification – Measurem easurements with higher higher charging cur-5 D iss is s ipat ip ation ion fact fa ct or: or : ±0.5 % ±1...5.10 rents, without shunt connection. This elim- Measurements are carried out by compariFrequency: 50...60 Hz inates the disadvantage of having to use son with a standard capacitor. It should be virtually loss–free and its capacitance and a correction formula. Calibration accuracy – Direct measurements of grounde grounded d test test dissipation factor must be known. ± 0.02 % Th The bridg bridge e is bal balan ance ced d by mody odyfying ing th the Resistances: objects. Tim Time con constant ants: < 1 · 10 10-8 sec. – Special Specia l measurements with with increased increased resistance decade, the slide wire, and the Capacitances (for tan ): ± 0.5 % sensitivity, e. g. for oil and foil tests, using capacitance decade until the null indicator's deflection is zero. a guard–ring capacitor. Frequency range – Measurem easurement sensitivity for Cx = 100 10 0 pF. pF. Depending on the circuit arrangement, the 10...1000 Hz Test volt oltage age = 1000 1000 V, V, f = 50 Hz: Hz: tan tan δ dissipation factor and the capacitance may either be read off directly or calculated by Measurements with lower or higher fre= approx. 1...2 .10-6. quencies according to special provisions. – Inductance Inductance measurements according accordi ng to to means of a formula – based on the resistances R3 and R4, the capacitance C4, and Standard calibration: 50 or 60 Hz. Maxwell and Hay. – Mutual induct inductance measurements ac- the standard capacitance values. All harm- Dimensions ful earth and partial capacitances are elimcording to Carey–Foster. 607 x 367 x 160 mm (24 x 14.5 x 6.3 in) inated due to a guard potential control. – Measurem easurements of electrolytic capacit capaci tors. – Capacit apaci tance measurements ents according according to Weight Wien. 20 kg (44 lb) All these circuit arrangements can be selected by means of one main switch.
Schematic diagram
arrangement No. 1 R3 = R4 =
0...1111 Ω 100 - 200 - 500 - 1000 2000 - 5000 - 10000 - 100/ π
S = 0.0 ...1.1 Ω
1000/ π - 10000/ πΩ N =
0.1 - 0.3 Ω
C4 = 50 pF...1.111 µF
1 - 2 - 5 - 10 - 20 50 - Ω
T1:
arrangement No. 2
I =
R3 =
Il =
0.1 - 0.3 Ω 1 - 2 - 5 - 10 - 20 - 50 100 - 200 - 500 - 1000
T2: I = bridge
2000 - 5000 - 10000 Ω R4 = 0...1111Ω
Il = guard
Legend CN , = Standard capacitor CX = Test sample R3 = 1. Resistance decade 2. Step-adjustable resistors R4 = 1. Step-adjustable resistors 2. Resistance decade R5 = Auxiliary resistor
N C4 G S T1 T2 Sch
= = = = = = =
Step-adjustable resistors Capacitance decade Galvanometer Slide wire with taps tan switch: large/ small tan Galvanometer switch Shield
Order specification
Standard capacitors
Scope of supply
– Compressed gas capacitor series 3370 (050/ 100 pF - 200...1200 kV)
Measuring bridge according to Schering type 2801. Ground cable 16 mm2 10 m (The connection cables are not included in the price) Optional supply
Electronic null indicator Oscilloscopic null indicator
type 5516 type 5517
Automatic guard potential regulator
type 2911
Auxiliary arm according to Wagner
type 2906
Shielded transformer (to match the input impedance of the null indicator to the bridge)
type 7651
External shunt, max. 20 A
type 2902
Precision current transformer (up to 2000 A) Current comparators: up to 400 A up to 2000 A up to 10000 A 2 -8
type 4732 type 4762 type 4761 type 4764
– Compressed gas capacitors 100 pF - 70 kV type 3380/ 100/ 70 100 pF - 100 kV type 3380/ 100/ 100 – Compressed gas capacitors 1000 pF - 20 kV type 3385/ 1000/ 20 1000 pF - 25 kV type 3385/ 1000/ 25 – Polystyrene capacitors 1000 pF -25 kV type 3360/ 1000/ 25 0,01 µF -1000 V type 3313 0,1 µF-1000 V type 3314 – Air capacitor series 3320 10/ 20/ 50/ 100/ 500/ 1000/ 2000/ 5000/ 10000 pF - 2000 V – Variable vacuum capa citor 5...250 pF - 2000 V type 3320/ 5-250 – Test cells for liquid instulants Heatable up to 150°C max. 2000 V type 2903 Test cell - max. 1000 V type 2905 – Test cells for solid insula nts Heatable up to 300°C max. 2000 V
type 2914
- Resistance decade 10 x 1000 Ω 10 x10000 Ω
type 1101 f spec. type 1101 g spec.
– Resistor box type 1153 10 Ω/ 100 Ω/ 1000 Ω/ 10 kΩ/ 100 kΩ for inductance measurements according to Maxwell and Hay, and mutual inductance measurements according to Carey-Foster – Ionization filter
type 7345
- Cables 1 cable to connect test type 111 WA object CX unipolar, double shielded with terminal box standard lengths: 2, 5,10, 20 m
1 cable to connect type 111 W standard capacitor CN unipolar, double shielded standard lengths: 2, 5,10, 20, m 1 cable to connect ext. type 101 W shunt type 2902 unipolar, shielded standard lengths: 1, 2, 5, 10, 20 m 1 cable to connect null indicator type 5516 or type 5517 bipolar, shielded length: 1 m
type 121/ 1
