INSTRUCTION PAMPHLET U-5743

Transcription

1 WABCC I! I,. INSTRUCTION PAMPHLET U-5743 INSTALLATION AND MAINTENANCE INSTRUCTIONS FOR UNION TRANSISTORIZED UNIT CARRIER INTRODUCTION The Union Transistorized Unit Carrier equipment is a keyed frequency type multi-channel carrier used to transmit CTC codes or to indicate single functions Figure 1... Unit Carrier Transmitter and Receiver PRINTED IN U.S.A. A UNION SWITCH & SIGNAL DIVISION Westinghouse Air Brake Company March 1964 PITTSBURGH, PA

2 WAEICC U-5743, p. 2 such as block occupancy. The completely transistorized unit provides communication by superimposing carrier on existing physical DC line wires, cable or voice circuits. Utilizing unit carrier equipment, several independent carrier circuits can be added to an existing pair of line wires or cable circuit. The transmitter and receiver units are designed to occupy a rack space equal to that of a standard style PN-150 relay. SPECIFICATIONS Frequency Range The Unit Carrier equipment is available in eighteen channels, one channel every 00 cycles ranging from 9KC to 21KC and every 2000 cycles to 31KC. Receiver and Transmitter Impedance Both the transmitter and receiver are designed to work into a 600-ohm line. When working with an impedance differing greatly from 600 ohms, matching transformers must be used. Transmitter Level The output level of the transmitter is designed to operate at a maximum of +6 dbm. The transmitter is equipped with an adjustable output control, located on the front of the unit, which permits adjustment of the output level. Receiver Sensitivity The receiver is designed to operate at a maximum sensitivity of -15 dbm. Sensitivity of the receiver is adjustable by means of a variable potentiometer located on the front of each unit. Receiver Output The receiver will deliver 0 milliwatts of DC power to a 400-ohm load. Additional loads can be connected to the receiver but may result in a slight loss of efficiency. Voltage Requirements All power required can be obtained from a standard - or 12-volt battery source. When carrier is being transmitted, the transmitter and receiver together draw a total of only 0. 4 watt from the battery (0. 1 watt for the transmitter and 0. 3 watt for the receiver), and when the transmitter "key" is open, during an "off" period of the code, the combined power consumption is only watt (0. 08 watt for the transmitter and watt for the receiver). Keying Speed Keying speeds of up to 35 cycles per second can be realized with the proper resistor-relay combination used on the receiver output. Size and Weight Each transmitter or receiver unit, including terminals, measures 2-7 /16 inches by 5-1/4 inches by 8 inches and weighs approximately 2-1/2 pounds. FREQUENCIES AND POWER LEVELS The direction of transmission of all carrier frequencies should be in accordance

3 WABCO with the AAR agreement which states that frequencies of 7KC to and including l 7KC shall be transmitted from East to West or North to South and frequencies of l 7KC to 30KC shall be transmitted from West to East or South to North. The carrier power output levels are in accordance with the AAR specifications for tone equipment of six decibels above the one milliwatt base (+6 dbm). APPLICATION The transmitter is a complete assembly and needs no additional material. The receiver is complete except for the receiving relay. The receiver is designed to operate a 400-ohm PN-150 relay which is generally utilized where the carrier circuit indicates one function. When it is necessary to use 120 or 180 code, a 135-ohm CD-F relay or a 360-ohm PC-250B relay with tuned electrical decoding can be used. Where keying at higher speeds is required, a 70/70 KP relay may be used, the coils connected in multiple with a 5-ohm resistor in series. This arrangement allows a keying speed of about 35 cps, although at this rate some pulse distortion may occur. Unit carrier equipment can be used on and directly connected to open line circuits which are arranged for carrier operation. Most existing lines which are used for voice communications can be used for unit carrier circuits with little or no change to existing facilities. If the line circuit to be used has cable insertions of over 1, 500 feet, matching transformers will probably be required at each end of the cable to properly match the cable to the open line wire or the unit carrier. If the line circuit is made up entirely of cable, matching transformers are required at each end. If the line circuit to be used is not engineered to handle the proposed unit carrier frequencies, it is recommended that measurements be made to determine the exact loss to carrier that actually exists. The measured attenuation will probably exceed the values derived from standard line wire and cable attenuation data, because the devices on the line may load the carrier and because of absorption losses to other line pairs. From the measured data, it can be determined if the proposed installation will be satisfactory. While the unit carrier is designed to operate over a 21 db circuit, allowances must be made for abnormal line attenuation because of weather conditions and equipment aging. The amount of this margin will depend largely on the degree of reliability required. When used on open line a 2:1 or 3:1 margin is often used, thus the normal total attenuation should not exceed 7 to db. When the circuit is entirely in cable, the attenuation does not vary greatly, therefore a normal attenuation of perhaps 15 db can be permitted. As can be seen from the foregoing, it is impossible to predict how many miles the carrier circuit can be operated without actual line data. However, open line construction will often permit operation over distances up to 35 miles. Operation in cable will vary from 3 to miles. CIRCUIT DESCRIPTION Transmitter The Transmitter Carrier unit comprises a Hartley-type oscillator and one stage of amplification which also serves as a buffer in preventing line conditions from affecting the oscillator. (See Figure 2. ) U-5743, p. 3

4 WABCC The oscillator circuit is made up of transistor SC!, coil Tl and associated resistors and capacitors. The frequency is controlled by capacitors C2, C7 and the primary coil on Tl. The second winding on Tl provides the feedback required. Tl cs + - N K Figure 2... Unit Carrier Transmitter Circuit The signal appears across the third winding of Tl and potentiometer RS, the output control. The signal is fed to the base of transistor SC2 connected as a common emitter class A amplifier. The DC emitter circuit is through R6 to terminal K. When the transmitter is keyed "off", this circuit is open. When keyed "on", terminal K is connected to Kl thus closing the emitter circuit to terminal B. The signal is fed to output transformer T2 which provides impedance matching to a 600-ohm load. Choke T3 and capacitors C4 and C6 make up the output filter which is tuned to the transmitted frequency. This filter blocks DC signals and harmonics of the fundamental frequency from the line circuit and provides a high impedance to other frequencies present on the line. Choke T4 and capacitor CS provide a filter on the battery input to the unit to block voltage surges, which may appear on the battery wires, from entering the unit and damaging the transistors. Receiver The Receiver Carrier Unit consists of a tuned input circuit, one stage of Class A amplification, one stage of push-pull power amplification, and a full wave rectifier. All stages are transformer-coupled. (See Figure 3.) The signal received appears across terminals Ll and L2. Choke T4 and capacitors Cl and C4 make up a tuned input filter which passes the desired frequency U-S743, p. 4

5 WAS CC and rejects all others. The filter also provides a high impedance to other frequencies on the line circuit. T3 R6 R3 R4 R5 R7 T5 + R8 C3 B N -R Figure 3... Unit Carrier Receiver Circuit Voltage of the desired frequency appears across the primary of Tl. The signal then appears across potentiometer Rl, the sensitivity control. The desired amount of signal is fed to the base of SCI which operates as a common emitter Class A amplifier. Capacitor CS and transformer T2 comprise another tuned circuit to improve the receiver selectivity. Any signal of a foreign frequency which may have passed through the input filter will be rejected here. The output of T2 is fed to the base of transistors SC2 and SC3 which are operated Class B push-pull. The secondary of T3 is connected to a full-wave rectifier to produce a DC receiver output suitable for energizing a relay. MAINTENANCE Test Instruments The test instruments listed below are recommended for shop and field maintenance of the Union Transistorized Unit Carrier equipment. These instruments will, in many cases, do more than is required for this application, but can be readily used in maintenance of most types of electronic equipment. 1. A Volt-Ohm-Milliammeter having a DC sensitivity of 20, 000 ohmsper-volt, such as the Simpson Model 260 Analyzer, is satisfactory for measuring all U-5743, p. 5

6 WRBCC DC voltage since extremely high internal impedances are not present in the unit carrier equipment. 2. A Transistor Tester, such as the Simpson Model 650 Add-A-Testor, capable of measuring moderate values of Beta as well as Ico is desirable. 3. A variable frequency oscillator, such as Hewlett-Packard Model 200CD Oscillator, which covers the 9KC to 31KC frequency range is required. 4. A vacuum tube voltmeter, such as Hewlett-Packard Model 400D or 403A Vacuum-Tube-Voltmeter, is necessary for measuring AC voltage. 5. In maintenance of any electronic equipment, visual observation of existing waveforms for evidence of overloading, clipping, and so forth, often proves to be extremely valuable in shooting trouble. Therefore, a good oscilloscope such as Hewlett-Packard Model 120-A Oscilloscope, should be available. 6. An electronic counter, such as Hewlett-Packard Model 521-C Counter, provides a most satisfactory method of checking carrier frequencies. It provides accurate data display which requires a minimum of time for interpretation. Transmitter Test Set-Up 1. Connect the transmitter to the test equipment as shown on the Transmitter Data Sheet, Figure ma. 2. Adjust B-N voltage to volts. The DC current drawn should not exceed 3. Rotate the transmitter output control, RS, to the maximum clockwise position. 4. Check the frequency being transmitted. It should be within 20 cycles of that called for on the nameplate. 5. Check the output voltage. It should be a minimum of 1. 5 volts. 6. If the unit is off frequency, it may be retuned by adjusting trimmer capacitor C7. When retuning, it is recommended that the frequency be adjusted to within 5 cycles of the nameplate frequency. 7. If the transmitter oscillator is retuned or the output voltage is slightly low, the output filter should be retuned. 8. Adjust trimmer C6 for maximum output. 9. The output waveform should appear as a sine wave on the oscilloscope.. If output signal is not present or an inadequate output is obtained, isolate trouble by performing point to point voltage checks as indicated on the Transmitter Data Sheet, Figure A sine wave should be observed on the oscilloscope at the input to the amr: lifier. The output wave shape should appear as a sine wave, except for a small amoun of clipping. U-5743, p. 6

7 Receiver Test Set-Up 1. Connect the receiver to the test equipment as shown in Figure Adjust B-N voltage to volts. The DC current drawn should not exceed 15 ma maximum with no input signal on Ll-L2. 3. Rotate the receiver sensitivity control, RI, to the maximum clockwise position. 4. Reduce the oscillator gain if an output greater than 6 volts appears across the 400-ohm load resistor. 5. Vary the frequency of the oscillator above and below the nameplate frequency. Note that the voltage across the 400-ohm load resistor peaks. Adjust the oscillator frequency to where the output voltage peaks. This frequency should be within 30 cycles of the nameplate frequency. 6. Adjust the signal level to produce 5. 7 volts across the 400-ohm load resistor. The input signal should not exceed -15 dbm. 7. Increase the signal voltage. The output voltage should saturate at about 7 to 7-1/2 volts and go no higher, even with increased input. 8. If the receiver is inoperative, perform the point to point voltage checks as indicated on the Receiver Data Sheet, Figure 6. WABCO 9. Connect the oscilloscope from collector to collector (PCB Reference Points 3 and 11) of the push-pull amplifier. With up to 5. 7 volts measured across the 400-ohm load resistor, a sine wave should appear on the oscilloscope. At 7. 5 volts output, a square wave will appear on the scope as the amplifier reaches saturation.. Through the input filter circuit, the Class A amplifier circuit and coupling transformer, a sine wave should be observed on the scope. 11. If the receiver is not on frequency, it may be retuned as follows: a. Temporarily remove the test leads from terminals LI and L2 (see Receiver Data Sheet) and reconnect to the outside terminals of potentiometer RI. b. Adjust the output of the oscillator until meter VI reads from to volt. c. Vary the oscillator frequency and note the frequency at which the output voltage peaks. This measured frequency should be within 30 cycles of the nameplate frequency. CAUTION If the voltage across the load resistor exceeds 6 volts, the input voltage must be adjusted to a lower value. d. If the measured frequency is not within 30 cycles of the nameplate frequency, the value of capacitor C5 must be changed. If the unit peaks at a frequency higher than that indicated on the nameplate, additional capacitance is required. (Use only high quality silver-mica capacitors.) After changing capacitors, the frequency response should be within 15 cycles of the nameplate frequency. U-5743, p. 7

8 WRBCC e. Remove the test leads from the outside terminals of potentiometer Rl and reconnect to terminals Ll and L2. f. Adjust the output level of the oscillator until a reading of 2 to 3 volts is measured across the 400-ohm resistor. g. Set the frequency to that called for on the nameplate. h. Rotate the adjusting screw of trimmer capacitor C4 for maximum voltage across the load resistor. CAUTION If the voltage across the load resistor exceeds 6 volts, the input voltage must be adjusted to a lower value. i. Vary the oscillator frequency and note the frequency at which the output voltage peaks. The frequency should be within 15 cycles of the nameplate frequency. step 6 above. j. After tuning the receiver, repeat sensitivity check as called for in U-5743, p. 8

9 DATA SHEETS W.ABCC

10 HEWLETT 400C OR PACKARO EQUIVALENT SCOPE VTVM ELECTRONIC FREQUENCY MEASURING SYSTEM JUMPER K I. Kt 0... K K1 TEST CIRCUIT 0 TO 150 OHM POT ELECTROLYTIC 2 WATTS OR HIGHER CAPACITOR IOOMFD.!IOV. + (HIGHER CAPACITY AND VOLTAGE MAY BE USED.) L1 8 L2 N 12-14V D.C. 0-IOV + SCHEMATIC DIAGRAM R cs II G G N K PCB REF. POINTS PCB. REF. POINTS AC Meter Pos. Neg. Pos. VOLTAGE Ground Lead Lead Lead Ll L (or over) l 4 l l 2 l DC VOLTAGE VOLTAGE TABLE B-N Input: Volts Output Control: Max. CW % Tolerance Battery } Key Closed - ma Current Key Open - 8 ma Figure 4... Unit Carrier Transmitter Data Sheet U-5743, p. IO

11 C7 C6 T2 R9 R8 RIO Tl R2 CAPACITORS RESISTORS TOL. U.S.& S. RES. TOL. U.S.& S. REF. MFO. % VOLTS PC. NO. USED ON REF. OHMS % WATTS PC. NO. USED ON CI.27 0 UJ All R2 lk ±5 0.5 UJ All C2.01 t2 500 Uj KC (two) R ±5 0.5 Uj7264 All.01 ±2 500 UJ7006!9 R4!OK ±5 o. 5 UJ All }!OKC.007 t2 500 Uj70!003 R6 56 ±5 0.5 UJ All.01 ±2 500 Uj R7 56 t5 o. 5 U All } l!kc.0025 ±2 500 UJ7006!5 RB 56 ± Uj All.01 t2 500 Uj700619!2KC R ±5 u.5 UJ72lu64 Ah.009 ±5 300 UJ ljkc.01,2 500 Uj7006!9.001 ±2 500 UJ }14KC.009 ±5 300 Uj l5kc.008 ±2 300 Uj70966 l6kc POTENTIOMETER.007 ±2 500 Uj70!003 l7kc RES. TOL. U.S.& S ±5 500 Uj & 19 KC REF. OHMS % WATTS PC. NO..01 ±2 500 Uj KC USED ON.009!5 300 Uj , 23 & 25KC Rl 50 ±IO 2.0 UJ62297 All.008 ±2 300 Uj KC.007 ±2 500 Uj70l003 29KC.0062 ±5 500 Ul JIKC CJ.22 ±20 0 UJ All THERMISTOR C4.008,2 300 UJ KC RES. TOL. U.S.& S..0062,5 500 Uj IOKC REF. PC. NO..003,2 500 Uj llkc USED ON.002,2 500 UJ KC RIO ±% UJ All.0015 ±2 500 UJ & 14KC.001 ±2 500 Uj & 16KC.002,2 500 UJ KC.001,2 500 UJ , 19, 20, 21 & 23KC TOROID INDUCTORS.0005,2 500 Uj & 29KC 25, 27 INDUCTANCE MH ±13\lb U.S.& S. c,.0004,2 500 Uj KC Uj70826 All REF. 1st winding PC. NO. USED ON Tl 15. l UN3851 9KC thru 13KC Cb * 500 Ul All.9 UN KC thru 19KC C " 500 UJ All UN , 21 & 23KC CB.001 ±5 500 Uj All 3.8 UN , 27, 29 & 3 lkc T3 63. l UN3854 9KC thru 16KC Micromicrofarad 36.3 UN KC thru 31KC TRANSFORMER U.S.& S. REF. TURNS PC. NO. USED ON TRANSISTORS T2 PR!. SEC. UN All to U.S.& S. REF. TYPE PC. NO. USED ON COIL SCI SC2 2N44 Uj All RES. TOL. U.S. & S. REF. TURNS OHMS \lb PC. NO. USED ON T ±IO UN All PARTS LIST Figure 5... Unit Carrier Transmitter Components U-5743, p. 11

12 600 OHM TO 3-15 OHM MATCHING TRANSFORMER. SEE TEXT,.--.. TEST Rx MUST BE NON- INDUCTIVE ANO COVER THE RANGE OF 200 TO 700 OHMS. LI L2 CIRCUIT 0 TO ISO OHM POT + 2 WATTS OR HIGHER ELECTROLYTIC CAPACITOR IOOMFO. SOV. (HIGHER CAPACITY ANO VOLTAGE MAY BE USED.) B N 12-14V o.c. o-1ov. + C4 T3 3 II LI 4 R6 l!iot BK 13ST L2 21 II R2 R4 20 RS R7 R8 SCHEMATIC DIAGRAM 20 + C3 TS 8 B BK N G -R PCB REF. Meter Ground POINTS Pos. Lead AC VOLTAGE PCB. REF. Neg. Lead POINTS Pos. Lead DC VOLTAGE Ll 1 9 L (varies with input) l VOLTAGE TABLE B-N Input: Volts Battery } Zero Input Signal - 13 ma Sensitivity Control - Max. CW Current 5. 7 V across load - 22 ma % Tolerance U-5743, p. 12 Figure 6... Unit Carrier Receiver Data Sheet

13 CAPACITOM TOI., u.u.,a. l\l!i', Ml'D, VOi.Ti PC, NO, UIIID ON Cl 150* A3,3 UJ KC lhru 13KC 120' u UJ , 17 I IIKC 68* n UJ , 20 21KC ai H UJ , H l a?kc a 3 i Ii',018 *2 300 UJ S,009 *5 IOKC Nott 300 UJ700S43 "Au,015 t2 300 UJ700620,005 ia aoo UJ llkc,015 d 300 UJ700620, KC UJ700612,01 u 500 UJ700619,008 i KC UJ700618,01 u 800 UJ700619,0025 i KC UJ700618,01 i2 500 UJ lskc, UJ KC.ooa i2 300 UJ KC, UJ KC, UJ700618,0018 d KC UJ700613, UJ700617, KC 2 aoo UJ700613, UJ7006!8 21KC,01 t2 aoo UJ KC, UJ KC.007 d 800 UJ KC, UJ KC,008.a aoo UJ KC, UJ700612,0008 u 500 UJ H, UJ700937, UJ700608,0002.a 500 UJ700603,0001 ts 500 UJ C6, UJ All (H required) NOTS "A": Unite tuned by meana of capacitors C5 ptua trimmers aa required. Micromtcrofarad DIODES u.s.&s. REF, TYPE PC, NO, USED ON DI D2 D3 D4 Tl2G UJ All POTl!NTIOMl!Tl!l\ " RIIS, TOI., u.a.11. l\111', OHMS WAffl PC, NO, UBIID ON l\l SOK uo 0,23 U All THlll\MlllTOl\ RIIS, TOI., u.1.,1. Riii', OHMS caa c PC, NO, USl!D ON l\5 25 i!0\16 U All TOl\OID INDUCTORS INDUCTANCB MH "13\16 u.s., s. RBP, 111 wlndlng PC, NO, USBD ON T2 9, 7 4, TRANSPOI\Mi!RS u.s.u. REP, TURNS PC, NO. USED ON Tl T3 PRI, " IO s UN All PRI, SBC, UN All IO COii. RBS, TOL, U, S, & S, REP, TURNS OHMS \16 PC, NO. USED ON TS 150 0,40 UO UN All TRANSISTORS u.s.u. REP, TYPE PC, NO, USED ON SCI SC2 2N44 UJ All SC3 PARTS LIST Figure 7... Unit Carrier Receiver Components U-5743, p. 13

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