
Originally Posted by
phezthie
less invasive? its possible but you should check first if your car's starter is of such type that its carbon brush can be inspected even without removing the whole starter itself, otherwise, you must be a bit familiar with electronic tools like ammeter and voltmeter to make initial analysis....
here it goes...
if carbon brush is accessible, check if its still in good state... pag mahaba pa at intack, meaning hindi pa pudpod at hindi nadudurog, basically ok pa starter mo. you can pressume na malinis pa starter at wala pang masyadong carbon o dumi na pwede mag cause ng poor conductivity...
pag maikli na or medyo malabot at madaling madurog, no choice but to remove na the starter for carbon replacement and cleaning... that way, may check na din kung hindi pa nasisira yung copper slots ng rotor (commutator)...
if you cannot access the brush, get a high capacity ammeter and i recommend another voltmeter unit... verify the specs of your starter and be sure to have a good battery in this test...
connect the DC voltmeter probe to battery terminals... take note of the polarity and the setting of VM (it must be set to DC)... connect the ammeter (also set in DC) to the starter in series ... take note of the rating scale, starter motor draws high current depending on its power rating...
get the initial voltage reading. thereafter, ask somebody to crank your engine and then note the consequent voltage reading (it should be lower than the initial). simultaneously, get the ammeter reading... do this 2 to 3 times...then, after getting those initial measurements, tell your help to crank the engine until is starts.... this time, note of the readings of both testers...
with your electrical data at hand (starter specs and testers readings), you can now compute if your starter is of high resistance (actually its inductance)...
these are other factors to be considered. the higher the resistance, the probability of poor conductivity be due to dirty rotor or deteriorating carbon brush, hence, needs to be serviced/cleaning.
however, if your engine started by drawing small current only and minimal deflection in the voltage reading, it is in good and healthy state...
if it draws too much current and the voltage drops considerably before it starts, thats a sign of starter going bad...
BTW, in the foregoing tests, we are of course pressuming that the starter's windings (both stator and rotor) are in good state... HTH
regards
phezthie