Instructions for Cleaning Relay Contacts
Contents
1. loading or an accidental short through the contacts should be smoothed with the burnishing tool unless burned or pitted or pitted enough to require replacement The burnishing should be done in a direction corresponding to the direction of the slide of the contact The use of erasers is recommended for the final polishing The round eraser is for use in a drill press the end of the eraser being rotated over the silver surface The rotating eraser should touch the silver lightly and should not be held in one place too long because this tends to overheat the silver contact The flat eraser is a hand eraser also used for polishing by stroking the silver in the direction of the contact slide In all cases the silver should be against solid backing so it does not become twisted to cause beveling of the surfaces Care should be taken to remove all eraser particles after polishing b Silver Impregnated Carbon Contacts The sharp tips of new carbons DN 11 wedge type only should be broken slightly by burnishing in a plane parallel to the springs The burnishing tool should be used for this operation This burnishing should produce a smooth surface having no undercuts caused by the edge of the tool After burnishing has been completed all loose particles should be removed with a camel s hair brush followed by a spray of alcohol 3 3 Final cleaning of contacts for shelf type safety relays Final cleaning of contacts can be performed as descri2. Service Manual 4560 645 Russell Street Batesburg SC 29006 Instructions for Cleaning Relay Contacts September 1999 An Ansaldo Signal Company 1999 Union Switch amp Signal Inc Printed in the U S A UNION SWITCH amp SIGNAL REVISION HISTORY January 1961 January 1997 September 1999 SM 4560 9 99 1 UNION SWITCH amp SIGNAL Cleaning Relay Contacts This service manual covers recommended methods for the preparation and cleaning of relay contacts on all shelf relays and plug in type safety relays 1 0 RECOMMENDED CLEANING MATERIALS Burnishing Tool T K Neuses Co No 3 316 nnnnnnnnnnnnnnnnnnnnnnnn J397187 Burnishing Tool P K Neuses Co No N318 Heavy Duty J397187 001 Paper Strip strips cut from 67 pound white Springhill Vellum Bristol Paper J793094 Also recommended commercially available Emery Paper Wet or Dry 600 Grit cut in strips Alcohol 1 Solvent Ethyl Alcohol Proprietary 190 or equivalent Note When using the paper strip clean the back contacts first and the front contacts last Discard the paper strips when dirty 2 0 CONTACT CLEANING PROCEDURE 2 1 Contacts that are severely burned a g Using 600 grit emery paper strip folded with the grit side out so that both contacts can be burnished simultaneously stroke the contacts in the direction of the contact wipe Using the burnishing tool stroke the contacts several times in the directio
3. bed in Section 2 0 SM 4560 9 99 3 UNION SWITCH amp SIGNAL Cleaning Relay Contacts 4 0 ORDERING INFORMATION A relay contact cleaning kit part number X451646 0901 contains one each of the following Burnishing Tool J397187 Burnishing Tool Heavy Duty J397187 001 Paper Cleaning Kit 50 strips 5 8 x 7 1 2 J793094 Individual items from the kit are also available when ordering the above item s individual part number 4 SM 4560 9 99
4. n of contact wipe Place the paper strip between the open contacts then close the contacts and withdraw the paper strip I Repeat step c several times if necessary Using the alcohol spray give the contacts a degreasing wash Place the paper strip between the open contacts then close the contacts and withdraw the paper strip Repeat step f several times if necessary 2 2 Contacts with heavy tarnish slightly rough or pitted surface a Perform the procedure in Section 2 1 steps b through g 2 3 Contacts with surface film or oxidation not pitted a Perform the procedure in Section 2 1 steps P and g SM 4560 9 99 Cleaning Relay Contacts 3 0 SPECIAL HANDLING OF CONTACTS FOR SHELF TYPE SAFETY RELAYS 3 1 Recommended materials Burnishing Tool P K Neuses Co Heavy Duty 2 J397187 001 Also recommended commercially available Round Rubber Pencil Eraser to 5 16 for use in drill press Flat Rubber Hand Held Eraser Alcohol 1 Solution Ethyl Alcohol Proprietary 190 or equivalent 3 2 Preparation of replacement or worn contacts a Flat Silver Tips Silver tips should be carefully prepared before contacts are adjusted Best service is obtained from a contact surface polished as highly as possible Care should be taken to avoid the coarse finish resulting from ordinary fine files Silver tips that have become burned or pitted from excessive
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