Maintenance Schedules

ANNEXURE-E

MAINTENANCE SHCEDULE OF RMPU AND AC CONTROL PANEL (CONVENTIONAL)

S N	Equipm ent/ fittings	Activity	Tri p	Monthly	IOH	POH
1	GENERAL
		a) Check the log sheet maintained in each AC coach and attained the defects recorded by escorting staff during run.	√	√	√	√
		b) Cleaning with vacuum cleaners only was not found to be effective due to sticky dirt. The cleaning options have therefore been increased and suitable method may be adopted as required for individual items in the panel.	√	√	√	√
		c) Check all the safety & protection devices are in working condition and not in by passed condition	√	√	√	√
		d) Replace defective/by passed   components including indication LEDs and lamps	√	√	√	√
		e) Remove fresh and return air filter by opening the access doors of the unit. Clean these filters with blowers, brushes and water tub after taking out the filters and place them gently in their place or replace with pre-cleaned / new filters and closed the doors properly. A cleaning jet will be available with AMC holder/Railway for this activity.	√	√	To be replace d  (on conditi on basis) during IOH	To be replaced during POH
		f) Check the working of RMPU in conjuction with control panel. Status of blower and condenser motor to be judged by running for any abnormality. Switch ‘ON’ RSW-1 and check all three pilot lamps (Red, Yellow & Blue) for RYB phases and power ‘ON’ indicating LED (Green) are glowing. Put     RSW-2     in     ‘ON’ position and keep RSW-3 in ‘VENT’ position and check that: Green   colour   indicating light for blower ‘ON’ is glowing and Blower fan is working	√	√	√	√
		g) Check the satisfactory operation of vane relay by stopping the return air flow	√	√	√	√
		h) Check the satisfactory operation of RMPU by moving RSW-3 in AUTO, MANUAL COOLING. This can also be verified from indicating LEDs (Green colour).	√	√	√	√
		i) Check the cooling system is working with one condenser fan.  This can be done simply by switching off MCB 2 or MCB 3. (During this check it should be verify that reasonable cooling is achieved with one  condenser and two compressors working)	√	√	√	√
		j) Check working of both RMPUs with either of the inverter on SGAC coaches provided with two-package unit. (The caveat on the use of single inverter has been added as a single inverter with  current setting of 32A cannot deliver full load of 2 RMPUs about 44A)	-	√	√	√
		k) Check Electronic thermostat works properly i.e. AC system “Cut off” & “Cut in” in Auto mode.	√	√	√	√
		l) Check the setting of time delay relay. As soon as power supply switched ‘ON’, first compressor should come in circuit after 2 minutes and second compressor after 30 second of starting of first compressor. (Ensure provision of electronic time delay relay as per RDSO specification of approved make)	-	√	√	√
		m) Check the tripping of heaters i.e. OHP1 & OHP2. To assess the tripping of OHP1 & OHP2, put RSW-3 on ‘MANUAL HEATING’ position with blower fan ‘OFF’. The heaters should trip within 5 minutes. “This item has been suitably modified after issue of Modification sheet no. RDSO/PE/MS/AC/0060 (Rev. 0) for removal   of   manual   heating   mode.   As manual  heating  mode is not available,  an alternate method to check OHP has been specified. Tripping time has been retained as 5 mins. As various types of sensors are in use- with different response time – data regarding the time taken for tripping with 65 degree limit would   be   collected   before   any   further change in tripping time.” (This activity shall be done as  winter related  precaution )	√	√	√	√
		n) Check that the compressor by pass switch RSW-5 is working satisfactorily. It shall be done simply by moving RSW-5 at various position. The respective LED shall glow.	√	√	√	√
		o)  Check   the   tripping   of compressor from high pressure and low pressure as under. *HP  1  & HP  2: Switch ‘ON’  the comp. with   condenser   fan   motor  ‘OFF’  from  its  MCB2   &  MCB3. Keep the unit in run condition in manual cooling mode. The comp. should trip within 10 mins from high pressure and HP 1 trip & HP 2 trip indicating LED will glow. High pressure (HP) cut out switch should be   reset   after   each   tripping.   Re- setting  of  the  HP  cutout  shall  be done manually.  However,  during POH, ensure that HP setting is 400-430 psig with the help of calibratedpressure gauge. *LP  1  &  LP  2:Switch  ‘ON’  the comp. with blower fan ‘OFF’ from its MCB. Keep the unit in run condition  in manual  cooling  mode. The  comp.  should  trip  within  10 mins  from  low  pressure  and  LP 1 trip  &  LP  2  trip  indicating LEDs will glow. Low pressure (LP) cut out switch should automatically be reset after each tripping. Ho wever, during POH, ensure that LP setting is 30-40 psig with the help of calibrated pressure wever, during POH, ensure that LP setting is 30-40 psig with the help of calibrated pressure gauge. in run condition  in manual cooling mode. The comp. should trip within 10 minutes from low pressure and LP 1 trip & LP 2 trip indicating LEDs will glow. Low pressure (LP) cut out switch should automatically be reset after each tripping. However, during POH, ensure that LP setting is 30-40 psig with the help of calibrated pressure gauge.	-	√	√	√
		p) Run the plants for 15 minutes (only to avoid discharge of batteries.) and check the current drawn by various equipments with the help of clamp tester (tonque tester) duly calibrated. Normal currents for various equipments and mode of operation are as under: Package unit in cooling mode 20 – 23 Amps. Compressor 07 – 10 Amps Condenser fan motor 1.5 – 2.1 Amps Blower motor 1.5 – 2.5 Amps. Package unit in heating mode 7.0 – 11 Amps	-	√	√	√
		q) Check visually cond. Fan blade and ensure there is no crack on the blade or hub. Check and verify of direction of rotation of condenser fans.	√	√	√	√
		r) Check and tighten mountings of blower, compressor and blower motors and ensure that it is in good condition.		√	√	√
		s) Ensure that capillary tubes are not in hanging position.		√	√	√
		t) Check capillary tubes provided for HP/LP cutout for  proper  support/ clamping. Their nuts should be properly tightened.			√	√
		u) Check for proper tightening of cover provided over  evaporator compartment.			√	√
		v) Check that the glass cover over  indication  PCB  is intact.			√	√
		w) Check earthing shunts in control panel as well as in RMPU are provided. The continuity check to be carried out. Earthing shunt should be earthed to coach body.			√	To      be replaced during POH on conditio n basis.
		x) Check canvas duct provided at return & supply air.Rectify or replace the same, if defective.			√	To be replaced with new during POH
		y) Run the plant in cooling mode and check that the condensate water from the drip  tray  is  easily  drained out. Clean the drainpipe if needed.		√	√	√
		y1)    Thorough    checking    of condensed/rain water tray including leveling, periphery, outlet pocket and pipe. In case surrounding paste is dry and brittle, re-pasting to be done			√	√
		z) Check solid anti-vibration mountings of compressors, condenser motors, blower motor and over- all package unit and replace on condition basis.			√	AVM for over all package unit to be replaced on condition basis
		aa) If less cooling is noticed, check the leakage of refrigerant  from  the  system by soap solution or leak detector. If leak is detected, it should be attended and re- charging or topping up of refrigerant gas in the system shall be done as per RDSO SMI No. ELPS/AC/SMI/14.	√	√	√	√
		ab)       Check       insulation resistance  of all the motors&    compressors    by    duly calibrated   500   V   megger. Attend     the     motors,     if insulation      resistance      of motor is less than 2 M ohm. It  may  be  done  from  the control panel. IMPORTANT: Disconnect LED   indication,   modified PCB     of     thermostat     & indication   light   connection during this activity.			√	√
		ac)   Check   for   physically damaged/jointed cable. Replace if needed.			√	√
		ad) Check for physically damaged conduit. Replace if needed.			√	To be replaced during POH
		ae) Checking & securing fixing arrangement of cover of RMPU with the roof including MS strip, fixing screws by threaded stud etc.		√	√	√
2	Refrigerant pipe line/capillary checks
		a)       Proper       clamping/ support			√	√
		b) Rubbing of capillary with SS sheet/channel or other parts of RMPU (Clearance to be ensured between capillary and SS sheet)			√	√
		c) Leakage from flare nut of HP/LP cut outs with soap solution		√	√	√
		d) Leakage from Feeler tube of OHP			√	√
		e) Strainer/Capillary/, Catchall filter and oil separator (if required on condition basis) to be replaced  by new  one while changing compressor/ condenser/ evaporator/ attending  refrigerant  choke up. (Caveat to follow the SMI regarding replacement of compressor)	√	√	√	√
		f)  Fire retardant Rubber packing for support of refrigerant pipeline to be replaced in every POH				√
		g) Insulation over suction pipeline   wherever   available to be replaced on condition basis				√
3	Compressors checks
		a) Holding clamps from top properly tightened.		√	√	√
		b)      Mounting      fasteners properly tightened.		√	√	√
		c) Leakage  from  suction  & discharge port.		√	√	√
		d)  Accumulator holding/mounting		√	√	√
		e)  Condensing area covers are properly tightened & not touching top of compressor body.		√	√	√
		f) Electrical terminal box is properly tightened & cables are terminated with lugs.		√	√	√
		g) Defective compressor to be replaced as per RDSO/PE/SMI/AC/0038 (REV-O)-2007. The Maneurope / Kirloskar to be replaced only by approved model of scroll compressors as per Rly Bd’s instruction vide letter no. 2006/Elect(G)/114/2 Pt 1 dated 14.06.2012.	√	√	√	√
4	Condenser fans motor/blades and Blower motor/impeller checks
		a)      Mounting      fasteners properly tightened.			√	√
		b) Electrical terminal box of motors is properly tightened & cables are terminated with lugs.			√	√
		c)  Double earthing shunts are provided.			√	To be replaced during POH on conditio n basis.
		d) Water deflector* of condenser motor (wherever provided) to be checked and replaced if found damaged/missing. (*Water deflector is the rubber pad to prevent rain water ingress from top)			√	√
		e)  Blade conditions  for  it’s fixing/cracking/breakage/ damage or touching with its cover. Rectify, if needed.		√	√	√
		f)  Ensure  proper  clamping of cable conduit			√	√
		g) Replace SS blades by FRP blades of condenser fans.			√	√
		h) Check normal running of the motors			√	√
		i) Overhauling   of  Blower   and condenser fan motors shall includes the following during POH: *The    incoming    motors    shall    be checked  for  abnormal  noise  and vibration. *Check bearing make and replace with specified make, if defective *The IR value of Motor stator shall be measured between motor terminal and frame  before  and  after  overhauling. The Value of IR shall not be less than 10  MΩ,  when  measured   with  1000 volt megger.  *Winding  resistance  of  motors  shall be measured  between  RY,  YB  &  BR phases. The winding    resistance    shall be   ±10%   of  resistance   declared   by OEM in cold condition.  *Check   closely   terminal   block   and connecting    lead    for    any    physical damage or any flash mark over      it. Replace that same, if not satisfactory.  *Perform   HV   (Di-electric   test)   on stator by applying 1.5 kV ac supply for one minute. During test the leakage current shall also be measured, which shall not be less than 1.0 mA.  *Run   motor   on   no   load   for   15 minutes and check the following: i)      Bearing     noise     - Normal noise ii)     Bearing    temperature    rise above ambient    -10°C iii)   SPM   reading   -20dBN       max. (Green zone)  *Measure starting current  of  motors on no load. It shall not be more than 10 times of normal runni9ng current. Similarly, the running current of motors shall  be  measured  and  it  shall  not  be more than 1.4 A.  *Spray water over running motor by jet  having  10  mm  dia  from  all  side. After spray check IR value.   There should be no fall of IR value.				√
		j) Ensure that stainless steel braided  rope is provided to avoid falling of motor. Any kind   of  sleeve   over   rope shall not be used.			√	√
		k) Ensure that impellers are properly tightened.		√	√	√
		l) Electrical  terminal  box is properly  tightened  & cables are terminated with lugs			√	√
5	Evaporator compartment
	A) Return/ Fresh air filters	a) Ensure that filters are not physical damaged.	√	√	√	√
		b) Ensure that there is provision to avoid wrong fitment in the filter as well as in RMPU.				√
		c)  Ensure  that  the  locking arrangement    for fresh/return  air filters  is all right.		√	√	√
	B) HP/LP/ OHP cutout switch	a) Check that the mounting fasteners are properly tightened		√	√	√
		b) Ensure proper clamping/ support of capillary tube connected  to HP/LP/OHP cutout switch		√	√	√
		c) Ensure the flare nuts are properly tightened.		√	√	√
		d) Ensure Control wire to HP/LP/OHP  cutout switches  are  properly clamped.		√	√	√
		e)   Ensure   the   covers   of these HP/LP/OHP cutout switch are properly screwed.	√	√	√	√
		f)  Ensure  proper  clamping of feeler tube of OHP switch.		√	√	√
		g) Remove the accumulated dust   over   feeler   tube   of OHP switch.		√	√	√
		h) Check  the gasket  of the access doors for leakage. Replace, if required.	√	√	√	To be replaced during POH
	C) Heater	a) Ensure proper mounting of heater		√	√	√
		b)  Ensure  proper  clamping of electrical wire to heater.		√	√	√
	D) Thermostat/vane relay	a) Ensure there is no any breakage of its mounting bracket		√	√	√
		b) Ensure Control wires are properly clamped.		√	√	√
		c) Remove dust accumulated over thermostat bulb of mercury in glass thermostat/sensor of electronic thermostat gently.		√	√	√
		d) Ensure there is no any breakage  to  vane  relay flapper and its micro switch is  working  by  stopping  the air flow through return air opening with the help of cardboard.	√	√	√	√
		e) Vane relays to be replaced on condition basis	√	√	√	√
		f) Sensor for electronic thermostat to be replaced on condition basis	√	√	√	√
	E) Evaporator coil	a)        Ensure  there  is  no damage of fins			√	√
		b) Ensure sharp less bend of capillaries and properly clamped.			√	√
		c) Ensure there is no air by passed			√	√
		d) Clean the coil,			√	√
		e) Check that the mounting fasteners are properly tightened			√	√
		(f) ) Ensure that the filler bulb of expansion    valve   is   properly clamped and insulated		√	√	√
	F) Access doors	a) Ensure its proper locking & gasket.	√	√	√	√
	G) Drip tray	a) Ensure U-trap/cups are provided at free end of drainage pipe.		√	√	√
		b) Checking and cleaning		√	√	√
	H) Cover of evaporat or compart ment	a) Ensure there is no water ingress inside the evaporator compartment or air leakage from the evaporator compartment. It shall be checked by running the plant under artificial rain  for  at least  15  minutes.  Water should not enter inside the evaporator compartment.				√
		b)  Check proper tightening of cover provided over evaporator compartment.		√	√	√
	I) Condens er area	a) Clean the condenser coil from inside with compressed air/water jet after opening the cover of condenser area .		√	√	√
		b)    Ensure    there    is    no damage of fins		√	√	√
		c)  Check that the mounting fasteners are properly tightened		√	√	√
		d) Provide fire retardant thermal insulation over suction line.			√	√
		e)   Ensure  there is no any obstruction in fresh air path.		√	√	√
		f) Ensure there is no any damage/cracks in structure frame of RMPU.			√	√
		g)  Ensure  proper  clamping of electrical conduit.			√	√
7	Control panel
		a) Ensure double earthing shunts are provided on back plate.			√	To be replaced on conditio n basis during POH.
		b) Check that the mounting fasteners are properly tightened			√	√
		c) Ensure that the terminal block separators are not in broken condition.			√	√
		d) Ensure that end locks on the DIN rail are provided.	√	√	√	√
		e)  Ensure   that  all  legend plate as per RDSO drawing shall be provided.	√	√	√	√
		f) Ensure that the power & control wires are properly tie clamped			√	√
		g) Ensure that the latest wiring diagram  of power & control  panel  are  provided, if not provide it.		√	√	√
		h) Ensure that the indication lamps for R,Y & B are mounted properly.		√	√	√
		i) Check mounting of relays/contactors   are properly tightened.		√	√	√
		j) Check & tighten all terminals in control panel. Cable    termination    should not be without lug of acceptable make.		√	√	√
		k) Ensure that the sinusoidal 110 V, 50 Hz, ac supply for control     transformer     has been taken from the inverter in case of SG AC coaches. It should  not  be  taken  from the bus bar provided in the control panel.		√	√	√
		l)  Check  the  proper tightening of 37 pin connector.		√	√	√
		m) Ensure make, type & range as per Bill of Material of  devices  provided  in control panel				√
		n) Check the milli volt drop across the 3 phase of contactor. Replace the contactor,  if milli volt drop is found more than the specified limit by OEM.				√
		O) Ensure locking of stopper, hinges and indication panel arrangement of control panel doors	√	√	√	√
		p) Ensuring accessories like 20 mm PVC end fittings, mesh guard of RMPUs, combed hinges, nut & bolts and knobs of rotary switches	√	√	√	√
8	Devices in control panel
	Rotary /Cam Switches	1.   Check   the   condition   of   the rotary switches for physical damage. 2.   Check  the  continuity  of  each phase  i.e. R,Y,B.  This  activity shall  be  done  by  putting  the knob  at  OFF  and  ON position. 3.   Do    high    voltage    test    by applying  1500  V for  one minute between all current carrying part shorted together and earth. 4.   IR value to be checked by 500 V megger.  It should  be more than 10 MΩ. 5.   Check programme sequence of switch  as  per  OEM’s catalogue. 6. Replace   thimbles/lugs,    if required. 7.  Tighten terminal & mounting screws.  Thread  of screw  must not be stack.				√
	MCBs	1.   Clean the MCBs with dry compressed air 2.   Check the condition of all MCBs for physical damage. 3.   Provide end locks, if it is not there. 4.   Tighten DIN rail screws 5.   Check the characteristic as under. SN Test current Result to be obtained Remarks 1 1.13 In No tripping 2 2.55 In Tripping The time s less  t and sh more secs. In= Rating current 6.  Check the proper function of dolly by hand				√
	Contact ors	1.            Clean the lower and upper part of the magnet after opening the top cover of the contactor using cleaning agent viz CRC or equivalent. 2.  Check continuity between the incoming and outgoing terminals. 3.  Replace contactor if, connection pin is loosened. 4.  Check continuity of magnetic coil. 5.  Clean the dust accumulated on the magnet surface gently. 6.  Measure pickup and drop out voltage. a)  Pickup voltage shall not be less than 85% of rated voltage in hot condition b)  Drop out voltage shall not be more than 20% of rated voltage in hot condition. 7.  Check average impedance & mili volt drop as under: Contact or model of BCH make Averag e impeda nce Max. Mili Volt drop CE15C N 2.5 MΩ 25 mv +				√
	Over load relays	1. Normally closed contacts shall be checked for continuity. 2. Check the function of NO/NC contact by putting the relay in manual mode. 3. Check the continuity of incoming & out going terminals after connecting it with contactor. 4. Check current setting of over load relays on test bench and correct as under: a)     OL-1         2.5  A For blower motor b)     OL-2          2.1 A For condenser motors & OL-3 c)   OL-4 & OL-5   10.0 A  For compressors 5. Replace thimbles/lugs, if required. 6. Tighten      terminal      & mounting screws. Note : Always keep the relays in manual mode to avoid chattering of contactors during service. NOTE:- Always keep the relays in manual mode to avoid chattering of contactors during service.				√
	Time delay relay	1.  Clean the complete assembly by compressed dry air jet. 2.   Check the condition of the all both the TDRs for physical damage. 3.  Replace thimbles/lugs, if equired. 4.  Tighten terminal & mounting screws. 5.   Check the time setting on test bench as under: TDR1 should energize in 2.00 min and TDR2 should energize in 2 min. 30 secs.		√	√	√
		6.   Replace TDR, if defective	√	√		√