Shutdown SIS Previous Screen Product: W HEEL LO ADER Mode l: 920 W HEEL LO ADER 75J C onfiguration: 920 W HEEL LO ADER 75J03573-UP (MAC HINE) PO W ER ED BY 3304 ENGINE
Testing and Adjusting 37-MT, 41-MT, and 42-MT Series Starting Motors Media Number -SENR3581-04
Publication Date -01/10/2008
Date Updated -24/10/2008 i01364920
No Load - Test SMCS - 1453-081 Table 1 Tools Needed 6V-7070
The following procedure is used in order to perform the no-load test after the starting motor has been repaired. The test should also be performed when the starting motor is removed from the machine. In order to completely check a starting motor, the complete procedure should be followed. To check the starting motor components, refer to the Testing and Adjusting section.
1. Illustration 1 shows a 24 volt system with two 12 volt batteries that are connected in series to a starting motor. Connect one 12 volt battery for a 12 volt system. Connect the positive side of the battery cable to the "BAT" terminal of the starting motor solenoid. Connect the negative side of the battery cable to the negative terminal of the starting motor. 2. As shown, connect an open switch between the "S" terminal and the "BAT" terminal of the solenoid. 3. Connect the multimeter red lead to the "Mtr" terminal on the solenoid. Connect the multimeter black lead to the negative terminal of the starting motor. 4. Use a phototach or a rpm indicator in order to measure the speed of the armature. 5. Close the switch. The measurements in Table 2 should be observed: Table 2 No Load Test Minimum Voltage
6. If the voltage is below the minimum, the batteries are low and the batteries need to be charged. Note: If the voltage is higher, the speed will be proportionally higher.
No Load Test Results The following information provides some results of a no-load test and the possible problems. 1. A rated current draw at a no-load speed indicates a normal starting motor. 2. A low free speed and a high current draw indicates: a. An increase in friction could be caused by tight bearings, dirty bearings, or worn bearings. A bent armature or loose field pole shoes that would allow the armature to drag are possible causes of increased friction. b. A shorted armature could cause a high current draw. This can be checked on a growler tester after disassembly. c. A grounded armature or a grounded field winding could cause a high current draw. Check for grounds after disassembly. 3. Failure to operate with a high current draw indicates: a. A direct ground in the terminal or field windings. b. The bearings cease to operate properly. This can be seen by turning the armature by hand. 4. Failure to operate with no current draw indicates: a. An open field circuit will cause a failure. The system can be checked for an open field circuit with a multimeter after disassembly. b. An open armature will cause a failure. Inspect the commutator for badly burned bars. c. Broken brush springs, worn brushes or high insulation between the commutator bars could prevent https://192.168.1.2/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb/productsearch/productheaderinfoframeset.jsp&calledpage=/sisweb/…
good contact between the brushes and the commutator. 5. A low no-load speed and a low current draw indicates: a. An internal resistance that is high is possibly caused by poor connections, leads that are faulty, a commutator that is dirty, and/or causes that are listed in step 4. 6. A high free speed and a high current draw indicates: a. A shorted field circuit will cause a failure. Check the field winding for shorts after disassembly. C opyright 1993 - 2013 C ate rpillar Inc. All R ights R e se rve d. Private Ne twork For SIS Lice nse e s.
Fri Nov 08 2013 08:43:24 GMT-0800 (Pacific Standard Tim e )