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TEACHING NOTES ON SIGNAL MACHINE & SOLAR PANEL

SIGNAL & TELECOMMUNICATION TRAINING CENTRE, BYCULLA, MUMBAI ( I S O 9001-2000 CERTIFIED )

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CONTENTS

PAGE NO.

SIGNAL MACHINE 1. Introduction and types of signal machine

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2. Main Parts of Signal Machine 3. Description of motor. 4. Snubbing. 5. Installation 6. Adjustment of friction clutch. 7. Conversion of UQ and LQ machine. 8. Maintenance and troubleshooting. 9. Do’s and Dont’s.

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Solar Panel 1. Introduction & construction.

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2. Components of solar panel.

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3. Technical specification.

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4. Solar energy system.

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5. Advantage and disadvantage.

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6. Installation and maintenance requirement and testing.

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7. Testing, application in signaling.

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IRS SIGNAL MACHINE 1. INTRODUCTION

In electro mechanical signaling territory an electrical signal machine is used to operate semaphore signals electrically. Disadvantage of mechanical operation of semaphore signal is 1. Range of operation is limited. 2. Maintenance is more 3. outside interference is more. Advantage of Electrical Operation: 1. No limitation for range of operation. 2. Quick operation because no question of stroke loss 3. Less maintenance work. A signal machine consists of a Dc series motor operating the signal through a reduction gear train and a circuit controller. The machine is also provided with a friction clutch hold off device and snubbing arrangement. The assembly is housed in a cast iron metal case with a case aluminum cover. The machine is suitable for working with LQ an UQ signal. IRS signal machine Drg. No. SA 23851 is suitable for working 2 aspect and 3 aspect UQ signals and signal machine Drg. No. 23852 is suitable for working LQ signal. Types of Signal Machine a. Upper Quadrant Machine. b. Lower Quadrant Machine.

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2. Main Parts of IRS signal machine. 1. Motor 2. Gears 3. Friction Clutch 4. Hold off device 5. Circuit controllers 6. Buffer spring 7. Normal locking arrangement. MOTOR: The motor is a DC series wound, 2 poles with high starting torque. Sealed oil- less ball bearings are provided on the armature shaft. The commutator and brush assembly are easily accessible for inspection and replacement. Description of Motor 1. Low voltage machine 2. hand generator type 3. Low Voltage Machine : It is rated to work at 10 VDC and consumes 3 Amp current. The max. time of operation for 0-45 is 10sec. And0-90 is 20sec. Hand Generator Type Machine: It work on 110 VDC and takes 0.5A to 0.6A. the operating time is same as that of low voltage machine. 4. Function of Different Parts Gears : The gear system consist of a gear train which has three set at reduction gear to reduce the speed of motor to that of semaphore arm. The

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5 signal shaft is attached to the gear wheel ‘A’. Pinion ‘A’ and gear B as also pinion B and gear C fitted to the respective shafts by keys mounted to the motor shaft by a key. The gears are designed on the metric module system with 200-pressure angle. Friction Clutch: The motor shaft is coupled to the clutch gear through a friction clutch. The friction clutch consists of two ferode-lined disc one in either side of the clutch gear loaded by spiral spring. The functions of friction clutch is 1. To absorb the shock to the mechanism when the semaphore arm is braked at “OFF” position and to eliminate damage to the hold off latch. 2. It enables the arms to be brought to “ON” position from “OFF” position when the arm is held in “OFF” position due to the failure of hold off device. Proper meshing of clutch gear teeth with the hold off latch piece is achieved by the inclination in the shaping of the clutch gear. The frictional grip between the clutch gear and motor shaft can be adjusted by running the castle nut acting on the compression spring. A spring is fitted to the latch piece of the armature bracket so that it can move up and down when approached by clutch gear from the inclined side without interfering with the position of the contact. The spring also helps for adjusting the gap between clutch gear and latch piece. Hold Off Device: It is mounted in the front of the motor shaft and consists of 1. An electromagnet with armature and two contacts. 2. Latch arm and latch piece. 3. Clutch gear. The electromagnet consists of two sets of winding.

Pickup coil 45 ohms

resistance (22.5 + 22.5 ohms) Hold off coil 580 ohms (290 ohm + 290 ohms) The hold off device is rated to work on 10v DC. It takes about 220ma for attracting the armature and 17mA to hold it. The hold off device must hold the mechanism in “OFF” position when a minimum of 85% of rated voltage is applied to its terminals.

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6 Initially the pick up coil with H contact in series is energized at 40-50 degree or 85-95 degree position of arm for UQ and 40-50 degree for LQ. When the armature is attracted the ‘K’ and ‘H’ contact are opened.

Opening of K

contact cuts off the supply to the motor and H contact bridge the pick up coil and hold off coil in series due to which it takes low current for holding the arm in “OFF” position. When the electromagnet is energized, the opening of ‘K’ contact cuts off the supply to motor and the rotation of the motor shaft gradually ceases. The latch arm detent face, now in contact with clutch gear vibrates and further reduces the motor speed. Just before the motor armature starts to reverse its direction of rotation due to the weight of the arm the latch detent is to lock the clutch gear and hold the arm. The resulting shock is absorbed by the friction clutch. When the ‘K’ and ‘H’ contacts are opened due to the armature’s attraction the travel of the outer movable contact should not exceed 2.5mm. Circuit Controller: this is mounted above the motor and is easily accessible for inspection and maintenance. The contact rollers are mounted on the shaft which is coupled to the semaphore arm through a pinion. Each of the contact roller can be adjusted to suit its function. Buffer Spring: Two buffer springs assemblies have been provided on the right hand side of the body for absorbing the shock from the sector gear when the signal arm motion is arrested This also enables the adjustment of signal arm at “OFF” position. Normal Locking Arrangement: this arrangement is provided to prevent the lowering of the signal by out side interference. This consists of i)

One fixed plate

ii)

One spring loaded movable plate

iii)

One lock pawl

iv)

One force drop spring

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Snubbing (Rectifier Snubbing): When the supply to the electromagnet is cut off the signal arm returns to “ON” due to gravity at high speed. If this speed is not restricted it will hit the stopper with a heavy force, which will cause damage to the machine, signal post, and semaphore arm itself.

So an arrangement called snubbing is

proved for the smooth return of the signal arm to “ON” position. To achieve this a diode in series with a 2 ohms resistance is provided across the motor.

When the signal arm returns to “ON” due to gravity, the motor armature rotates and causes an emf to be generated in the armature due to the residual magnetism in the field. The generated voltage, which is in opposite direction to that of normal operating supply, circulates a current through the snubbing diode resistance, and through its own field. The circulating current develops an opposite torque on the armature and restricts the return speed of signal arm, and the signal arm return to “ON” position smoothly. INSTALLATION: Before installation check the following: 1. The cover is provided with suitable gasket and wire entrance is sealed to make it watertight and dust proof.

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8 2. The machine has been properly cleaned greased with graphite grease ‘A’ No. 0 to1 is 408 and oiled with light grade lubricating oil as per IS-1628. 3. After fitting the signal machine, adjust the aspect as shown below. a. UQ – 1. Stop 00 +/- 50 2. Caution aspect – 450 +/- 50 3. Proceed Aspect 900 +/- 50 b. LQ - 1. Stop 00 +/- 50 2. Proceed Aspect - 450 +/- 50 4. Operate the machine to caution and proceed aspect and check the position of arm when hold off device is operated if required carry out adjustment. 5. Use of signal arm angle indicator gauge for measuring the angular position of the arm. 6. Check that contact springs rest on the contact segments properly and both springs keep riding on the contact segment till arm assumes the proceed or caution aspect. 7. Check the hold off circuit contact segment come in circuit between 400 to 500 and again at 850 to 950 in case of U.Q. working and 400 to 500 in case of LQ working. OPERATION CIRCUIT 1. Push pull operation in circuit diagram. -- 1 2. Pull pull operation in circuit diagram -- 2 7. ADJSUTMENT OF FRICTION CLUTCH i)

Take out the split pin and remove nut and spiral spring.

ii)

Withdraw clutch assembly from shaft. If the assembly is tight tap with a wooden mallet.

iii)

Separate the friction disc from the clutch gear wipe the clutch disc off old grease with a clean cloth. Don’t use waste cotton.

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iv)

Apply graphited grease A No. 0 to IS 408 or any other good quality clutch grease and reassemble as follows.

Steel disc., friction disc, clutch gear friction disc, steel disc, spiral spring and nut. Ensure while fixing of the clutch teeth that inclination of the clutch gear teeth is in the right direction. So that it hold the signal arm in the off position by engaging with latch piece. V. tighten the adjusting nut till its top-case coincides with the face of the shaft. vi. Operate the signal several times,. Ensure that the slip of the pinion is of the order of ¼ to ½ turn when the semaphore arm is beaked at. This is done by tightening or loosening the adjusting nut. Insert the split pin to lock the nut in position. 8. CONVERSION OF UQ & LQ machine 1. Change the filed coil connection in motor. 2. Turn the latch piece by 1800 3. Position of friction clutch ratchet wheel to be turned by 1800 and lock pawl to be tuned by 900 and refixed. 4. Position of holding plates, fixed and loose and lock pawl to be turned by 900 and refixed 5. Section wheel to be positioned reversed by 900 and adjusted as per LQ position. 6. Circuit controller contacts to be adjusted as per LQ working. 7. Loop wire between terminal 2 and 6 to be provided, links between terminal 1 &3 and 5&7 to be removed. 8. UQ semaphore spectacle to be replaced by LQ spectacle.

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MAINTAINENANCE AND TROUBLE SHOOTING 1. Tighten the check nuts screws, and bolts where required. Open the split pin 2. Check that no oil drops on circuit controller, contact segments, and contact springs. 3. Drain out any oil accumulated at the bottom of the case 4. Use good quality light grade lubricating oil premium to IS 1628. 5. Check that the operation of gear IV arm is smooth and free from noise. 6. Inspect the contact surface. If they are pitted, clean with fine emery cloth ”o” size. Motor: 1. Inspect the commutator surface, if it appears rough, clean by holding a fine emery cloth “00” size evenly to the commutator and rotating the motor shaft. Clean any dust that maybe left on the surface. 2. Check the wear on the brush. If the wear is such that the tensioning spring touches the brush carrier replace the brush. 3. Before fitting the new brush, ensure sitting of its working surface on the curvature of the commutator face. FAILURES: 1. SIGNAL FAILS TO “off”(SAFESIDE) Probable Cause: a. Weak Batteries. b. Loose battery connection or fuse blown off c. Arm contacts not making properly d. Grease oil dust or dirt in contacts e. Faulty motor bearing. 2. Signal arm does not hold in “OFF” position(safe side) a. Hold off mechanism defective. b. Hold off arm contact not making properly.

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11 3. Signal Arm does not return to normal after controlling relays de-energized and/or signal levers put back to normal (unsafe side failures) a. residual magnetism in hold off coil b. Jamming of Armature c. Foreign feed d. Jamming hold off lock pawl. 10. DO’S AND DON’T’S DO’S 1. Check and tighten bolts, nuts and screws 2. Keep split pin open 3. Clean the circuit controller contact 4. Ensue the contacts making and breaking properly. 5. Check and remove any pitting in contact 6. Check commutator & clean if necessary. 7. Replace worn out brush 8. Check for proper function of friction clutch. DON’TS 1. Don’t stick armature with foreign materials. 2. Don’t clean armature or core with emery paper. 3. Don’t use waste cotton for cleaning friction clutch disc 4. Don’t use oil in the friction clutch disc. 5. Don’t forget locking and sealing.

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SOLAR PANEL 1. INTRODUCITON SOLAR PANEL. In a solar panel the solar cells convert sunlight into electric (electrical energy) based on the principle of photovoltaic effect where as conventional cells, converts chemical energy into electrical energy. In this process heat or temperature of sunlight plays no role. A solar panel consists of number of solar cells, which are connected in series/parallel configuration to provide specific voltage & current and is known as solar module A number of solar panels/modules are combined in series/parallel or both configurations, and then it is known as solar array. It is a semiconductor diode; silicon is used with impulsing phosphorus & boron for production of positive & negative energy. Thus there are two layers of silicon one layer is doped with phosphorus and other with boron. Process: 1. Absorption of sunlight into semiconductor. Generating of free charges Separating of +ve & -ve energy of different regions of the cell to produce E.M.F. 2. COMPONENTS: Components of solar panel. 1. solar Cell : 36 series connected, 100mm mono crystalline silicon round cells. 2. Transmission glass : tough & high transmission glass 92% 3mm thick. 3. Encapsulant: ethylene vinyl acetate. 4. Frame : Anodized aluminum 5. Frame Seal : Silicon 6. junction Box: For external screw terminal connection with by pass diode & blocking diode.

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13 Technical Specification: 1. Nominal voltage – 12v 2. Open ckt. voltage – 21.60v 3. Short ckt. current – 2.60 A 4. Maximum power – 35w 5. Nominal power – 35w 6. Frame material – aluminum

Solar Energy System: Solar cells produce energy only when illuminated to ensure steady & constant power in dark or cloudy periods following equipments are used. 1. Solar panel 2. Storage battery 3. Blocking diode 4. A regulator/controller Solar Panel: It generates power. Storage Battery: Stores the power for use in dark or cloudy periods. Blocking Diode: Prevents the battery discharging back through the solar panel at night. Voltage Regulation: Avoids excess charging of battery. AC Load: Watt requires x numbers of appliance = Watt required(Total) Watt required (Total)x Number of operations X duration of each operation = Watt hrs. Watt Hr/12= Daily load (AH) with 12v system Daily load/Inverter efficiency = Adjusted daily load DC Load: Watt required X No. Of appliances=Watt reqd. (Total) Watt reqd..(Total)x No. of operation x Duration of each operation in hrs=Watt hrs. Watt Hrs/12 = Daily load (AH) with 12v system Total Daily load = Total AC load +Total DC load Battery Efficiency

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4. Advantage: 1. No external fuel required. 2. Sunlight – free of cost 3. Unlimited life of high reliability 4. Can operate under high temperature 5. Inherently short ckt. protected 6. pollution free. 7. Minimum maintenance 8. Suitable for remote, isolated & high plates 9. Can be used with secondary cells for non-sunshine period. 10. It can work under an electric lamp where limited power is required. 11. It can generate power from Mw to mw Disadvantages: 1. Initial cost is high 2. Dependent on sunlight 3. Additional cost for storage battery. 4. Climatic conditions location latitude, altitude, bird dropping etc. affect the output. INSTALLATION AND MAINTENANCE REQUIREMENT It shall be installed in such a way that: 1. It can receive maximum directs sunlight during only part of the day. 2. It shall not be accessible 3. It should be installed in such way that rain water bird droppings leaves etc. are not accumulated on panel. 4. Once in 15 days the surface of the panel should be cleaned with wet rag to remove dust, bird dropping etc.

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15 TEST OF SOLAR PANEL Test Circuit: A 100 w bulb is placed 15-20 cms. Above the cell, should generate about 0.5Votlage and at least 25%fo the cells rated current. APPLICATION IN SIGNALLING 1. Semaphore signal lightening at night. 2. Charging battery to power signal lightening & point machine. 3. Solar power radio warning system/gate signal/HKT/Track Ckt. 4. Solar powered RRI/PI/RELAY operation. 5. Charging secondary cells for token less/token block Instt. 6. Lightening outer/Warner signal and distant signals with motor operation.

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