IRS POINT MACHINE IRS POINT MACHINE is rotary locking type point machine and designed to comply with IRS specification S-24/2000 and RDSO Dr.No.S10.800. it is designed operate all type of points /switches. It is available in two model low stroke (143mm) and high stroke (220mm) It is non-trailable type point machine

Important feature Sr Nob Description remark 1 Type D.C. high thrust (stroke 143mm) 2 Other model High stroke 220mm 3 Type of Locking Rotary type 4 Locking of switches Independent (two lock slides) 5 Arrangement for Locking of switches Indirect through ground connections (rods) in side machine 6 Thrust 700 Kg 7 Over load protection Friction clutch self adjustable 8 Snubbing Mechanical 9 Locking of throw Available 10 Number of control contact 2+2 11 Number of detection contact 12 Greasing nipple 13 weight 220 Kg 14 packing Wooden skeleton 15 Number of ground connections Five (02 lock+ 02 detection + 01 through)

General Features of point machine The basic design of point machine generally comprises of Cast iron casing and cover with locking arrangement Motor Reduction gear Crank handle mechanism Friction clutch Contact assembly with spring loaded rollers and Detection slides Rotary to linear conversion mechanism Locking and throw assembly

Cast iron case accommodates all the parts of point machine is made of cast iron and designed to fix all parts at required place. provide access to/ slots for different lock and detection slides facilitate fixing of machine on sleepers Provides an arrangement to drain out water/ oil in bottom of casting. Provides cable entry.

Cast iron case

COVER OF POINT MACHINE Made up of thick iron sheet and fixed on cast iron casting (case) Contain lock ( S&T maintainer's lock) on inner side surface to lock it with cast iron casting (case). Secure all the parts of machine in weather proof environment and prevents un-authorosed interference. Provides access only to nominated (ward &feather) crank handle insertion. All the apertures for keys and crank handle are secured by flaps All flaps has a locking arrangement

COVER OF POINT MACHINE Cover top view Cover inner view Flap for crank handle key lock Flap For Cover key Flap For Crank handle Cover top view Cover inner view

MOTOR DC motor IRS: S 37 Motors for Electric Point Machine. shall comply with the requirements of IRS: S 37 'Motor for Electric Point machine. Motor comprises of crank handle cutout contact assembly, DC motor reduction gear

CRANK HANDLE AND CRANK HANDLE MECHANISM It allows Manual operation (without power) of point It require in case of failures of point/ point machine OR for the purpose of maintenance of point machine. It contain CRANK HANDLE AND KEY CRANK HANDLE CUTOUT CONTACT ASSEMBLY

CRANK HANDLE This apparatus is used for manual operation of point machine It is a “Z” shape structure made of steel pipe and has wooden handle on one end to have better gripe. Wards &feathers are welded on other end of pipe facilitates coding (insertion of only to nominated crank handle). A stud is intrude in the pipe, it get engage in forked shaft of motor Wooden handle Ward & feather Crank handle

CRANK HANDLE CUTOUT CONTACT ASSEMBLY It disallows simultaneous power and manual operation of point machine to protect staff performing crank handling. Ordinarily crank handle can not be inserted in machine Turing of crank handle key permits/ allows insertion of crank handle in the machine. Turning of crank handle key isolates the negative power path of motor. It comprise of Crank handle cutout contacts flap cover plate Crank handle key

Crank handle cutout contacts 1 1 There are two sets of contact These contacts are wired in negative path of power supply to motor. Contacts break / open with insertion and turning of crank handle key Makes when crank handle key is taken out. 2 Crank handle contact closed & Flap in front of shaft Crank handle contact open &Flap displaced & shaft visible

Flap cover plate & key controls the entry of crank handle in the machine for manual operation metal flaps attached to a lock hangs/ placed in front of motor shaft at the entry point of crank handle. flap cover plate is displaced by means of a crank handle key The insertion and turning of crank handle key displace the flap cover plate to allow insertion of crank handle open crank handle cutout contacts. Removal of the crank handle key replaces flap cover in front of motor shaft makes the crank handle contact. Crank handle key

Flap cover plate and crank handle key Flap cover plate in front of crank handle Entry & shaft of motor Crank handle insertion Insertion & turning of key displaces flap Cover plate

DC motor is a series split field DC motor Is design to work on 110volt DC Is a series motor to meet high initial torque requirement Is split field so that motor can be rotated in both direction contains four field windings and two windings are connected in series to form a set of winding. Use carbon brushes

Technical parameters of motor Sr Nob Description Remarks 1 Type D.C. Series split field 2 Operating voltage 110 Volt DC (60 volt mini) 3 current 2 to 2.5 Amps 4 Thrust 700 Kg 5 Power 0.48KWt 6 Reduction ratio (in side motor) 20.8 :1 7 AC immunity 160 , 300, 400 volts 8 Power supply terminals 03 9 Insulation grade of windings More than 10 M Ohms

DC MOTOR main parts Armature and commutator Field winding Carbon brushes Motor body Groove for crank handle

DC motor Reduction Gear Rec Power Terminal Pinion Commutator & brush

Armature and commutator Function of armature To carry current crossing the field thus creating shaft toque To generate an electromotive force Function of Commutator Reverse the current in moving coil of motor’s armature and generate a steady rotating force (torque)

Field winding The function of the field winding create magnetic field for armature motor contains four field windings two windings are connected in series to form a set of winding. one set of winding rotate motor clockwise and other set of winding rotate motor anticlockwise direction

Carbon brushes Brush is rectangular carbon block and spring loaded in holder Brush provides the electric connectivity between field windings and rotating commutator the holders should be mounted a maximum of .125" above the contact surface. Proper functioning of the holder depend upon, Inside holder dimensions equally Holder spacing Holder angle (20 to 30 deg.) Holder height Spring force (4.0-6.0 PSI) Electrical connections Carbon brush

Reduction gear It is trail of gears which provides reduction ratio 20.8:1 Number of teeth on driver Reduction Ratio = ------------------------------------- Number of teeth on drive Reduction ratio provides a torque-speed conversion from a higher speed motor to a slower but more forceful output. Motor rotate at very high speed and Load can not be directly placed on motor shaft. Appropriate reduction gear ratio is used to get require mechanical advantage/ thrust to syncronised various functions to change direction of rotation to get desire power as

Reduction Gear Oil entry pinion pinion Hover flow pipe

Friction Clutch Friction clutch is an assembly of spring loaded Gear, shaft and disks which are placed between motor and Load (point throw / transmission assembly). Functions of friction clutch are To protect the motor from overload To achieve mechanical (dynamic) snubbing To follow the sequence of point operation.

Transmission assembly Lift out disc Control disc Drive disc Lock segment Gear rim slip rim pinion

Feature of friction clutch The friction clutch designed to extend stroke (force) from motor to load (point) if load is within Specified limit (700 Kg) de-clutch (separate) motor and Load (point) if load is more Specified limit (700 Kg). De-clutching of friction clutch can be adjusted to suite Specified limit of load (700 Kg) by loosening Or tightening spring. Friction clutch require / needs an adjustment if slipping current /obstruction current shall not be more than 1.6 to 2 times of normal working current difference between normal working current and slipping current /obstruction current is less than 0.5 Amps. The friction clutch shall adjusted in workshop only (not at site).

Parts of friction clutch Friction clutch comprises of Control disc Lift out disc Drive disc Gear rim and slip rim Shoe expansion (locking plate) Helical spring

Sequence of rotation of gear &disc How different gear and disc rotate in side friction clutch Pinion of motor rotates Gear rim, then Gear rim rotates slip rim then slip rim rotates shoe expansion, then shoe rotates lift out disc and drive disc, then d.disc rotate control disc and shaft with pinion & lock pawl

Control disc It is a circular disc with notch on outer periphery Notch for top roller It is a circular disc with notch on outer periphery Edges of notch are vertical Function of control disc are Allow the top roller (roller A) to fall in side respective notch at end friction clutch rotation Prevent upward movement of top roller (lock the top roller) Control disc outer view Studs for non trail able block Control disc inner view

Lift out disc It is circular disc with notch on outer periphery. It has notch on inner periphery also which engages with shoe expansion. It has two grooves which are fill with grease & fitted with two grease nipples. It is first disc to rotate in friction clutch. Function To lift the top roller (roller A) to open detection contacts at beginning of point operation Notch on inner periphery Inner view Grease Nipple Outer view

Drive Disc Drive disc is a Thick circular disc & has Two projections on outer and inner periphery. A shaft keyed in the center Lock pawl and pinion fixed on one end of shaft Lock pawl and pinion fixed at180 degree opposite A circular offset on outer periphery on which gear rim rests Two studs which engaged with non trailable block. A Small window to have access to friction clutch adjustment nut.

Shaft pinion Window Lock pawl Projection on outer periphery Projections on Inner periphery Shaft pinion Locking face For throw slid Window Circular groove For gear rim Lock pawl Locking face For lock slids

Functions of Drive Disc Extend movement to shaft hence rotate pinion and lock pawl. Restrict rotary movement to 270° and provide subbing Hold gear rim on outer periphery Convert rotary movement in to linear movement

Gear rim & spring loaded slip rim It is main part of friction clutch where rotary movement of motor is extended to other parts of machine Overload protection to motor achieved Snubbing is achieved The main parts are Gear rim Slip rim Shoe expansion with helical spring

GEAR RIM & SPRING LOADED SLIP RIM Shoe expansion gear rim Helical spring

Gear Rim A circular gear having 92 teeth on it’s outer periphery It engages with pinion of the Motor It Accommodate slip rim and spring loaded shoe expansion. When rotated by motor It transmits rotary motion to shoe expansion through slip rim

Slip rim It is semicircular rim with grips on it’s outer surface. It’s width is less than the width of gear rim Rotate freely within gear rim when not loaded by spring. When spring loaded it rotate with gear rim

Shoe expansion (locking plate right & left) and helical spring Two rectangular steel strips hold by a clamp at one end. Other end butted against slip rim ends. Shoe expansion extends rotary movement of gear rim to lift out & drive disc. Helical spring placed between shoe expansion in compressed condition. Compressed spring compel gear rim and slip rim to act as one piece

Sequence of rotation of gear &disc How different gear and disc rotate in side friction clutch Pinion of motor rotates Gear rim, then Gear rim rotates slip rim then slip rim rotates shoe expansion, then shoe rotates lift out disc and drive disc, then d.disc rotate control disc and shaft with pinion & lock pawl

How friction clutch performs? During normal course of operation During obstruction At end of operation

Friction clutch during normal course of operation Pinion operates gear rim slip rim & shoe expansion rotates along with gear rim as these are spring loaded in side gear rim the edge of one shoe expansion engages in the notch on inner periphery of lift out disc & lift out disc rotates the same edge of one shoe expansion engages with projection on drive disc also & drive disc rotates shaft rotates along with drive disc & stroke of 143mm generated

Friction clutch during normal course of operation Gear Rim Projection on Inner periphery Of drive disk Slip Rim Shoe expansion

During obstruction The drive disc cannot rotate, as throw bar/gear rack is stationary Hence shoe expansion engages with projection on drive disc also cannot rotate. But pinion of motor forced to rotate gear rim Hence rotary force will appear on other shoe expansion The helical spring get compressed & slip rim collapse to reduce circumference of slip rim The gear rim alone rotates with slight friction between gear rim& slip rim.

During obstruction Gear Rim Projection on Inner periphery s Of drive disk Slip Rim Shoe expansion

Friction clutch at end of operation At end of operation projection on outer periphery buts with bottom rod Obstruction is generated inside the machine Friction clutch slips & snubbing is achieved.

Friction clutch at end of operation Drive disc Bottom bar

CONTACT ASSEMBLY WITH SPRING LOADED ROLLERS Contact assembly comprises of two spring loaded contact groups which are fixed inside the casting. Function of the contact assembly: - make and break the sets of contact. One group Contains two sets of contact fixed side by side Contact controls feed (Power) to motor and point indication relay

CONTACT ASSEMBLY WITH SPRING LOADED ROLLERS Each Contact group comprises of Eight terminals in two sets for wires termination terminals sets fixed opposite to each other on the casting Eight high tensile contact (metal strips) in two sets. Two sets of contact are fixed back to back on spring loaded bracket / crank. Two sets of roller are fixed on same spring loaded bracket / crank. Bottom roller and top roller A transparent cover protects all sets of contact and terminals The transparent cover has sealing arrangement also. Control contacts Control contacts Bottom roller Top Roller

CONTACT ASSEMBLY WITH SPRING LOADED ROLLERS Terminal and finger contacts are insulated from metal part of point machine. Two Finger contacts are shorted at one end Carbon tip is fixed on other end of Finger. Outer side two sets of contact are known as Control contact and inner side two sets of contact are known as Detection contact. These contacts are self wiping, they clean themselves during the process of making and opening.

PARTS OF CONTACT ASSEMBLY

Making of contacts Making of contact depend upon position of top and bottom roller on the periphery of control disc and detection slid respectively. Detection contact in one group & control contact in other group makes when top roller fall in nominated notch on friction clutch bottom roller fall in nominated notch on periphery detection slid Falling of top roller in notch proves correct locking of point Falling of bottom roller in notch on proves correct setting of switches / points. Bottom Roller Inside notch top Roller Inside notch top Roller outside notch

Detection contacts Making of Detection contacts proves correct setting and locking of switches. Detection contacts are classified as Normal detection contact (ND) and reverse detection (RD) contact. ND contact make when point correctly set and lock in Normal. RD contact make when point correctly set and lock in Reverse. if point is not set correctly and/ or not correctly locked then both ND contact and RD contact are remain in open condition. ND contact and RD contact are used circuit of point indication relay NWKR and RWKR respectively.

Check for Correct setting and locking of point The notches on detection slides and friction clutch can be make available for bottom and top roller by moving lock slides and detection slides. Dose it Mean that ND & RD contacts can make even though point is not lock and set? proving of correct setting and locking of point by ND & RD contact is subject to condition that length of ground connections between point slides are accurately adjusted. This is prime check to be done at site during installation & Maintenance

Control contact Feed to motor is control through these contacts Control contact controls feed to motor in normal course of working Types of Control contacts Normal Control contact (NC) Reverse Control contact (RC). When points set and lock in Normal then RC contact makes. When points set and lock in Reverse then NC contact makes. When point is not correctly set and/ or not correctly locked position than both NC contact &RC contact are remain in make condition. NC contact controls feed for reveres to normal operation of point RC contact controls feed for normal to reveres operation of point. NC and RC opens as soon as point correctly set and lock in required position.

Detection slides D Type detection slid Threaded Stud Small notch Brass stripe Threaded Stud Small notch Wide notch C Type Detection slid

Detection slides These are two rectangular strong metal strips and two threaded rods are welded at one end. Each slid have a small and a wide notch on its one of surface. These slides are connected to switches of point and used to prove correct setting of switches. Bottom Rollers of switching unit are mounted on surface of these slides. Threaded studs welded sideways to avoid interchanging position of slides Rectangular Brass strips are riveted on inner surface Brass strips avoids transfer of movement to other slid which is supposed to be stationary in case of rod breakage

Lock slides

Lock slides These are two rectangular strong metal strips and two threaded rods are welded at on end. Each slid have a small and a wide semicircular notch , These slides are connected to switches of point and used to lock the switches. Lock segment on drive disc engages in these notches Threaded studs welded sideways to avoid interchanging position of slides Rectangular Brass strips are riveted on inner surface Brass strips avoids transfer of movement to other slid supposed to be stationary in case of rod breakage

Position of point/ Switches Position of Notches on Lock slid Position of top Roller ND For RHS mounting RD RHS mounting NC RHS mounting RC RHS mounting Control/lift out disc Bottom roller LHS mounting When switching unit is not fixed on machine Make Open open Set in normal but not locked Available On periphery of control disc & lift disc 1,1a 5,5a 2,2a 6,6a Not Available Hanging on notch of detection slides Set and locked in normal In the notch of control disc & lift disc 3,3a 7,7a In the notch of detection slides 4 ,4a 8 ,8a 5 ,5a Set in reverse but not locked Set and locked in reverse