FLUKE Y5020 Instruction 电路图.pdf

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1、 Instruction Manual Model Y5020 Current Shunt P/N 516591 September 1979 RadioFans.CN 收音机爱 好者资料库 Y5020 RadioFans.CN 收音机爱 好者资料库 Y5020 1 INTRODUCTION The Model Y5020 is a precision, four-terminal, current shunt designed for use in calibrating ac/dc current sources in the range of 0 to 20 amps, do to 5

2、kHz. The shunt is housed in a forced-air cooled, PTI (Portable Test Instrument) case. This case is compatible with all instruments in the Fluke PTI product line and can be stacked with other PTI products to form a portable test system. Forced-air cooling is accomplished by a fan mounted on the rear

3、panel. Air is pulled in through the fan, passed over the shunt, and exhausted through the rear panel. Power for the fan is derived from the power line. Two voltage configurations are available, 115 or 230V ac 10%, 50 to 60 Hz. Four front panel terminals provide electrical access to the shunt; two ar

4、e current input terminals and two are voltage output (sense) terminals. When the shunt is connected into a circuit and operating at its maximum current limit (20 amps), the input connections and the shunt present a burden voltage of less than 0.25V dc. SPECIFICATIONS Specifications for the Y5020 Cur

5、rent Shunt are given in Table 1. INSTALLATION The Y5020 PTI case is designed to stack with other Fluke instruments in the PTI product line. Use the following procedure to stack the Y5020 with the other PTI instruments. 1. Locate and pull the black latches on both sides of the unit to their extended

6、position. 2. Place the unit on top of the PTI stack with the front panel toward the front of the stack. 3. When the unit is properly seated push both latches to the in position. This will lock the Y5020 to the stack. CONTROLS AND CONNECTORS The front- and rear-panel controls and connectors on the Y5

7、020 are shown in Figure 1 and described in Table 2. OPERATING NOTES Input Power Line power requirements for the Y5020 are specified on a decal located on the bottom side of the unit. These include line voltage requirements (115V or 230V ac 10%, 50 to 60 Hz) and replacement fuse types. Input power is

8、 used solely to power an internal cooling fan. A front panel POWER switch allows the fan to be turned on and off. Fuse Replacement The Y5020 includes a fuse to protect the ac power line from an accidental overload. If replacement is required, use a 1/8 amp, 250 volt (AGC) fuse. Use the following pro

9、cedure to replace the fuse: 1. Set the POWER switch to OFF and disconnect the unit from line power. 2. Locate the fuse holder on the rear panel. Table 1. Y5020 Specifications NOMINAL RESISTANCE ACCURACY OF CALIBRATION VALUE DC DC to 1 kHz 1 kHz to 5 kHz STABILITY OF CALIBRATION VALUE MAXIMUM CURRENT

10、 BURDEN VOLTAGE AT 20 AMPS TEMPERATURE COEFFICIENT POWER COEFFICIENT POWER PROTECTION CLASS 3 0.01 1% .01% .01% .025% .035% (30 ppm per 6 months) 20A dc or rms ac Less than 0.25V 0.001% per C 0.005% at 20 amps 115V ac 10% or 230V ac 10%, 11 watts for cooling fan. Relates solely to insulating or grou

11、nding properties as defined in IEC 348. RadioFans.CN 收音机爱 好者资料库 Y5020 2 12 6 54 3 Figure 1. Controls and Connectors Y5020 3 Table 2. Controls and Connectors REF NO. NAMEFUNCTION 1VOLTAGE OUTPUT TerminalsA pair of binding posts that serve as the sense connections to the four- terminal shunt. The maxi

12、mum sense voltage at 20 amps is 0.2 volts. 2CURRENT INPUT TerminalsTwo binding posts that serve as the current input connections to the shunt. The maximum current rating for the shunt is 20 amps. 3POWER SwitchA push-push type switch used to switch the cooling fan on and off. 4Input Power ConnectorA

13、three-prong connector used to connect the instrument (via the power cord) to line power. 5Fuse HolderHolds the line power fuse for the cooling fan. The fuse provides ac input protection from overloads. 6Fan Intake and Exhaust PortsCooling air for the shunt is pulled in through the rear-right port (i

14、ntake) and exhausted through the rear-left port. The fan is located behind the intake port. 3. Release the fuse by pressing in on the fuse cap and turning it 1/8 of a turn counterclockwise. Use a suitable screwdriver. CAUTION To avoid fire hazard use only a 1/8 amp, 250 volt (AGC) fuse replacement.

15、4. Install the new fuse in the fuse cap and install both in the fuse holder. Forced-Air Cooling CAUTION To ensure the accuracy specifications of the shunt, do not apply input current to the Y5020 unless the cooling fan is energized. The Y5020 is equipped with an internal cooling fan to ensure the ac

16、curacy and stability of the shunt over its operating range (0 to 20 amps). The fan pulls the air in through the rear panel, passes it over the shunt, and exhausts it through the rear panel. Power for the fan is derived from the ac power line. A front panel POWER switch is used to turn the fan off an

17、d on. Four-Terminal Measurements The Y5020 is a four-terminal current shunt. Two terminals (CURRENT INPUT) are used to carry the current to be measured. The other two (VOLTAGE OUTPUT) are voltage sense terminals and are not designed to carry any measurement current. These sense terminals are connect

18、ed directly across the shunt. When current is passed through the shunt, the IR drop developed across it can be read at the VOLTAGE OUTPUT terminals using a high impedance voltmeter (,10 MW). Since this voltage reading does not include the IR drop of the current carrying conductors leading up to the

19、shunt, it provides an accurate indication of the current flowing through the shunt. Nominal Shunt Resistance The current shunt used in the Y5020 has a nominal resistance value of 0.01 ohms. This value was selected for two reasons. First, the low resistance minimizes the voltage drop (burden voltage)

20、 developed across the shunt. As a result, the shunt has a negligible affect on the circuit into which it is inserted. Second, the voltage drop across the shunt relates directly to the current flowing through it. For example, a current of 1 amp will produce a .O1 volt output. This relationship is lin

21、ear over the current range (0 to 20 amps). Actual Shunt Value The actual resistance value of the shunt is recorded in the lower-right corner of the Y5020 front panel. This value is traceable to the National Bureau of Standards, and must be considered when required current accuracy is better than 1 p

22、ercent. Y5020 4 Voltmeter Requirements Accurate current measurements require the use of a highimpedance (10 M) digital voltmeter to measure the shunt voltage appearing at the OUTPUT TERMINALS. In addition, the voltmeter should have a voltage accuracy of at least 0.01%, and be capable of resolving 10

23、 V on a 200 V range. The use of a voltmeter that does not meet or exceed these requirements will degrade the accuracy of the current measurement. Current Calculation Precise current measurements require that the current value be calculated using the SHUNT VALUE and the voltage present at the VOLTAGE

24、 OUTPUT terminals; i.e., I = VOLTAGE OUTPUT/SHUNT VALUE. For example: SHUNT VALUE = .0100363 VOLTAGE OUTPUT = .050182 Current = .050182/.0100363 = 5.0000498 amps OPERATION With reference to the previous paragraphs use the following procedure to operate the Y5020: 1. Connect the Y5020 to the line pow

25、er and set the POWER switch to ON. 2. Connect a suitable voltmeter (ac or dc) to the VOLTAGE OUTPUT terminals, observe polarity. 3. Select the 200 mV range on the voltmeter. 4. Remove power from the circuit to be measured and connect the Y5020 (as if it were an ammeter) into the circuit using the CU

26、RRENT INPUT terminals. Observe polarity. 5. Energize the circuit under test and derive the measurement current using the SHUNT VALUE and the voltmeter reading. THEORY OF OPERATION The Y5020 Current Shunt, as shown in Figure 2, is a precision, four-terminal current shunt designed for use in measuring

27、 ac/dc current in the range of 0 to 20 amps, dc to 5 kHz. Measurement current is connected at the CURRENT INPUT terminals and passed through the shunt resistor. The voltage drop developed across the shunt is picked off at the shunt sense terminal and carried to the front panel VOLTAGE OUTPUT termina

28、ls. Current flowing through the shunt is directly proportional to the voltage present at the VOLTAGE OUTPUT terminals, i.e. I = E/ R. VOLTAGE OUTPUT SENSE CURRENT CURRENT INPUT HI HILO LO 01W Figure 2. Current Shunt MAINTENANCE Access/Disassembly To access the interior of the Y5020 remove the four s

29、crews on the bottom of the unit and pull the top cover from the bottom cover. All components are accessible with the top cover removed. The shunt is a plug-in assembly and may be pulled out for inspection, repair and/or replacement. Do not bend the shunt elements during the removal process. Calibrat

30、ion The Y5020 is not equipped with any calibration adjustments. However, the SHUNT VALUE given on the front panel should be verified every 180 days by a calibration facility with NBS traceability. LIST OF REPLACEABLE PARTS A list of replaceable parts for the Y5020 is given in Table 3. Components are

31、 listed alphanumerically be assembly. Electrical and mechanical components are listed by reference designator. Each listed part is shown in an accompanying illustration. Parts may be ordered directly from the manufacturer by using the manfacturers part number or from the John Fluke Mfg. Co., Inc. fa

32、ctory or authorized representative by using the FLUKE Stock Number. If an ordered part has been replaced by a new or improved part, the replacement will be accompanied by an explanatory note and installation instructions, if necessary. Y5020 5 To ensure prompt, efficient handling of your order, incl

33、ude the following information: 1. Quantity. 2. FLUKE Stock Number. 3. Description. 4. Reference Designation. 5. Printed Circuit Board Part Number and Revision Letter. 6. Instrument Model and Serial Number. SCHEMATIC DIAGRAM A schematic diagram of the Y5020 is shown in Figure 4. Table 3. Y5020 Final

34、Assembly Y5020 6 Table 3. Y5020 Final Assembly (cont) Y5020 7 MP11 (2) MP15 MP7 MP2 MP1 Y5020-5001 (1 OF 2) H8 (4) H4 B1 SEE SHEET 2 OF 2 FOR DETAIL MP13 MP8 (2) MP19 (2) MP14 (4) H8 (2) MP16 (2) H11 (2) H2 (2) Figure 3. Y5020 Final Assembly Y5020 8 Y5020-5001 (2 OF 2) J4 MP21 A1 H6 (2) J5 J2 J3 MP9

35、 MP24 MP10 J1 (REF) #18 GR/YEL WIRE MP5 MP4 H5 (2) MP18 R1 H6 (2) MP22 F1 XF1 MP6 (2) MP3 MP23 (2) H12 (2) H3 (2) H1 (2) H6 (4) R1 (REF) MP17 H9 (4) MP20 (4) SEE DETAIL 1 TO J1 (GRN/YEL) TO B1 (WHITE) H2 (4) H7 (4) H10 (4) MP24 (2) H1 (2) J1 H1 (2) S1 DETAIL 1 #22 BLACK WIRE #22 BLACK WIRE MP22 (REF) XF1 (REF) F1 #22 WHITE WIRE H1 MP24 TO B1 (WHITE) H1 Figure 3. Y5020 Final Assembly (cont) Y5020 9 HI F1 A1 LO LO J3 P3 J2 P2 R1 S1 FAN RED BLK J4 P4 HI LINE POWER VOLTAGE OUTPUT CURRENT INPUT Figure 4. Y5020 Schematic Diagram Y5020 10