Dynamometer Maintenance Guide
Contents
1. a Excessive lubricant will cause bearings to overheat Tunnion Bearing Grease Unless specified otherwise trunnion bearing grease is general purpose industrial NLGI No 2 grade mineral oil with a lithium base Recommended trunnion bearing greases are listed in Table 7 1 Manufacturer Brand Name Shell Alvania No 2 Table 7 1 Recommended Oil Specifications for Rotor Bearings Oil lubricated rotor bearings require a high grade mineral oil free from water sediment acid resin and other substances not derived from petroleum products and resistant to rust and oxidation Recommended oil specifications are listed in Table 7 2 according to operating temperature and rotating speed of bearings Also refer to drawings and contract specifications Ambient Temperature Range Viscosity of Oil at 38 C 100 F in Saybol Universal Seconds S U S Po Under 2000 RPM 2000 to 6000 RPM Over 6000 RPM 18 to 4 C 0 to 40 F 160 200 120 160 92 100 4 to 38 C 40 to 100 F 200 320 160 200 120 160 38 to 66 C 100 to 150 F 320 540 200 320 160 200 Table 7 2 Oils Provided by Dyne Systems Oil types provided by Dyne Systems are based upon the oil system supplied with the dynamometer These are listed below in Table 7 3 Oil System Oil Type Constant Level Oiler Exxon Nuto H 68 Oil Circulating System Mobil Nuto H 32 Oil Mist Lubrication System Mobil Mist Lube 27 Table 7 3 42 Dy2. DyneSystems Inc Midwest amp Dynamatic Dynamometers Water Cooled Eddy Current Dynamometers MAINTENANCE GUIDE Excerpt from User s Manual www dynesystems com SECTION 7 CHECK LIST INSPECTION MAINTENANCE Service life of a dynamometer and the quality of test results depend on routine maintenance received during its lifetime Inadequate maintenance increases the probability of sudden and catastrophic failures Routine maintenance is the best assurance of trouble free operation The purpose of this Maintenance Section is to guide users in setting up a good maintenance program Although many factors affect the service life of any machine this manual cannot cover all contingencies but it can assist experienced maintenance personnel in maintaining the dynamometer in foreseen conditions Refer any questions to DS Service Department A checklist should be prepared which includes all maintenance check points pertaining to the equipment The following is a list of suggested items to be included on such a checklist 1 Nameplate information 2 List of drawings 3 Speed Ranges 4 Load Ranges 5 Coil Ratings including voltage current and cold resistance 6 Water Service including normal drain temperature GPM required and pressure 7 Lubrication Service including type of grease type of oil viscosity 8 Air Service including type and pressure 9 Safety Settings including low coolant pressure high cool
3. Water pressure oil pressure or temperature switch open Vibration from imbalance or misalignment Bearing failure Improper mounting Shaft coupling loose Overloaded Lack of coolant Defective modulating valve Plugged cooling passages Bearing damage High thrust load Lack of or wrong lubricant Misalignment Bent shaft Controller malfunction Overload causing collapsed rings and locked rotor Safety interlock operating Cooling or lubricant failure Erratic Operation Controller malfunction Trunnion bearing binding Load measuring system malfunction Surging coolant Defective bearing Speed feedback malfunction Torque feedback malfunction Electrical noise Loose electrical connection Dynamometer not statically balanced Hoses binding the dynamometer carcass Trunnion bearings dirty or worn 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 5 1 2 3 4 1 2 3 4 5 6 7 8 9 1 2 3 4 Load cell linkage is loose Table 8 1 Troubleshooting Guide 46 Dyne Systems WATER COOLED EDDY CURRENT DYNAMOMETERS 8 Troubleshooting DPD 002 01 Copyright Dyne Systems Inc
4. aft by hand to lubricate bearings and alternate shaft position to prevent brinelling Store in clean dry area within the following temperature limitations 10 C 50 F to 50 C 120 F Humidity should not exceed 60 Open all airtight coverings to permit air circulation Vibrations from heavy moving vehicles can be transmitted through the floor Avoid storage in heavy traffic areas as bearing damage may result Prepare an anti rust water mixture of 50 parts water to one part DuPont No 7 Rust Inhibitor to prevent rusting inside dynamometer carcass cooling passages and sump Pump mixture into normal coolant inlets and allow drainage in normal manner Operate Wet Gap dynamometers at minimum of 1750 rpm Dry Gap dynamometers do not require rotation Drain anti rust water mixture To prevent damage from coolant freezing open drain cocks or pipe plugs provided Tag dynamometer to indicate drains are open For protection of oil lubricated bearings prepare an anti rust oil mixture Select a high grade mineral oil resistant to rust and oxidation with a viscosity of 200 to 320 S U S at 38 C 100 F Mix four parts oil to one part Quaker Ferrocote No 5684 If constant level oilers are used drain oil from the system refill with anti rust oil mixture Elevate oiler to ensure oil flow into bearing cavities Relocate oiler in proper position and turn shaft by hand to coat bearings On a monthly basis rotate shaft by hand to lubricate bearings a
5. ant temperature low oil pressure 10 Alignment Data including angular and parallel maximum limits 11 Vibration including normal readings 12 Service Record including date or maintenance cycle when above test points should be checked 13 Repair Record including date and description of problems versus items repaired or replaced During routine maintenance visually check for loose bolts missing shaft guards coolant or lubricant leaks and excessive dirt on cooling surfaces Question the operator to determine if abnormal conditions exist or a change in operation has been noted Compare operation of unit with its performance profile Investigate any changes noted on check list Carefully check air filters strainers and auxiliary support devices Dyne Systems WATER COOLED EDDY CURRENT DYNAMOMETERS 7 Maintenance 41 DPD 002 01 Copyright Dyne Systems Inc CLEANING If filters or screens are plugged or dirty remove and clean them When they cannot be properly cleaned replace them Clean equipment of excessive dirt oil and other contamination that may work into the unit and cause a problem LUBRICATION Absorption dynamometers include two types of bearings trunnion and rotor Trunnion bearings are grease lubricated Rotor bearings are lubricated with either constant level oilers a pressurized re circulating oil system or grease Do NOT mix brands or types of lubricant unless manufacturer guarantees compatibility A
6. ly tighten the screws on either the pedestal caps or enclosure top Check TIR of the shaft It should not exceed 0 001 Make sure the coolant pressure gauge is functioning properly Make sure the exit coolant temperature switch is functioning properly Remove temperature sensor and check with calibrated thermometer using water Check the Y Strainer filter if applicable and clean if needed For pressurized re circulating oil system check filters and screens and replace them if they cannot be cleaned Make sure the solenoid valve is functioning properly For pressurized re circulating oil systems drain clean and change oil Check the trunnion bearings to make sure grease is not dry or hardened If required repack with fresh grease or replace bearings Check vibration using an Accelerometer e 3600 RPM and less should not exceed 0 20 V in sec e 3601 RPM and greater should not exceed 0 15 V in sec 44 Dyne Systems WATER COOLED EDDY CURRENT DYNAMOMETERS 7 Maintenance DPD 002 01 Copyright Dyne Systems Inc STORAGE 12 Months or Less Greater Than 12 Months Store in clean dry area within the following temperature limitations 10 C 50 F to 50 C 120 F Humidity should not exceed 60 Open all airtight coverings to permit air circulation Vibrations from heavy moving vehicles can be transmitted through the floor Avoid storage in heavy traffic areas as bearing damage may result On a monthly basis rotate sh
7. nd alternate shaft position to prevent brinelling If a pressurized re circulating oil system is used drain oil from system refill with anti rust oil mixture described above Connect circulating pump to proper electrical service and run pump for minimum of two hours On a monthly basis rotate the shaft by hand to lubricate bearings and alternate shaft position to prevent brinelling Greased lubricated trunnion and rotor bearings should be hand rotated and repositioned monthly to redistribute bearing grease and to prevent brinelling When placing dynamometer back into service drain anti rust oil mixture from oil piping system and replace with recommended oils See Tables 7 2 and 7 3 Inspect grease lubricated trunnion and rotor bearings and repack with recommended grease refer to Table 7 1 If using a closed loop cooling system flush the dynamometer prior to putting it back into operation Dyne Systems WATER COOLED EDDY CURRENT DYNAMOMETERS 7 Maintenance 45 DPD 002 01 Copyright Dyne Systems Inc SECTION 8 TROUBLESHOOTING The possibility of a component failure or other problems always exists This section of the manual is intended to provide assistance in finding the fault Check the obvious first then follow the Trouble Shooting Guide 15 0 111 POSSIBLE FAULT Dynamometer will not Load Dynamometer Stops Operation Controller malfunction no coil excitation Loose or incorrect wiring Defective field coil
8. ne Systems WATER COOLED EDDY CURRENT DYNAMOMETERS 7 Maintenance DPD 002 01 Copyright Dyne Systems Inc MAINTENANCE SCHEDULE GUIDELINES DAILY Check Oil Level The following are only guidelines if the dynamometer is used extensively or in a harsh environment the maintenance schedule will need to be adjusted accordingly Please choose the instructions below that pertain to your type of system Constant Level Oiler 1 2 It should be between 12 and full Do NOT over fill Turn the reservoir bottle counter clockwise Lift the bottle from oiler Fill bottle using Exxon Nuto H 68 librication oil or similar oil Quickly install bottle on oiler Oil will flow from the bottle until the bearing chamber and tube of the oil have been filled with oil Fill the bottle as many times as necessary until the oil level in the bottle remains constant The oil level must be visible in the transparent bottle of the oil reservoir at all times while the dynamometer is in operation Do NOT allow the reservoir to run dry the factory for proper operation of the constant level oiling system This position must The position of the oilers with respect to the bearing centers has been established at never be altered Pressurized Re Circulating Oil System 1 2 MONTHLY It should be between and full Do NOT over fill Remove oil reservoir cap Fill to appropriate level using Exxon Nuto H 32 lubrication oil or other
9. similar oil Replace oil reservoir cap Check coolant hoses for cracks Replace as required Check for coolant leaks Repair as required Check for oil leaks Repair as required Dyne Systems WATER COOLED EDDY CURRENT DYNAMOMETERS 7 Maintenance 43 DPD 002 01 Copyright Dyne Systems Inc EVERY 3 MONTHS 1 Check Carcass Movement 1 Loosen or remove the anti rotation safety stop and disconnect the Load Measuring System from carcass Gently move the torque arm up and down to verify that the carcass moves freely in the trunnion bearings If the carcass does NOT move freely check for interference such as wires hoses brinelling of the trunnion bearings dry or hard trunnion bearing grease etc Reconnect the Load Measuring System to the carcass and tighten or reinstall the anti rotation safety stop 2 Rotate Trunnion Bearing Rotators Shift Rings if applicable 1 2 EVERY 6 MONTHS ANNUAL Disconnect the Load Measuring System from the Carcass Depending upon type of dynamometer loosen the screws of either the pedestal caps or enclosure top Rotate each 2 rotator about 15 by hand using a rod that fits into the machined holes of the rotators Gently move the carcass by hand It should move freely without binding or restriction If the carcass does NOT move freely check for interference such as wires hoses brinelling of trunnion bearings dry or hard trunnion bearing grease etc Secure
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