Hello few days back i serviced the starter motor of my motorcycle. brushes were partially worn but they were in spec according to the manual. i got this question while i was doing it. my starting system has been working fine. i checked the starting system with a multimeter after servicing my starter motor. i just needed to make sure everything was ok. otherwise there was no need to do it.
anyway when i test the starting system with the multimeter i can see the normal voltage drop which we see in both cars and motorcycles. every time i press the self start button the battery voltage drops from 12.8V to 10V (roughly). when i honk the horn i can see a slight voltage drop too. on my horn they have printed it as 12V 5A. so its amperage value is there. but on my starter motor (brand is MITSUBA) i can't see any amperage value. both positive and negative wires of the starter motor is very thick. so apparently it draws more amps.
but my questions are,
1) what makes this voltage drop. does more amperage draw always mean a voltage drop ? since voltage is the potential difference how potential drops as the current (amps) rises through the circuit ?
2) what makes the starter motor to draw more amps than the motorcycle horn? is that the resistance inside the device (motor) which directly affects the amperage? if we apply V=IR we can see that as we increase the resistance the amp value drops. if we decrease the resistance the amp value rises. but that's assuming the voltage is constant. so i'm not sure it's practical to apply it for this example ( sorry i have a very basic knowledge ).
3) is there a way to check the amp value of the starter motor? i have used volts,ohms,diode and continuity modes in my multimeter but haven't used it to measure amps so far.
thank you very much
anyway when i test the starting system with the multimeter i can see the normal voltage drop which we see in both cars and motorcycles. every time i press the self start button the battery voltage drops from 12.8V to 10V (roughly). when i honk the horn i can see a slight voltage drop too. on my horn they have printed it as 12V 5A. so its amperage value is there. but on my starter motor (brand is MITSUBA) i can't see any amperage value. both positive and negative wires of the starter motor is very thick. so apparently it draws more amps.
but my questions are,
1) what makes this voltage drop. does more amperage draw always mean a voltage drop ? since voltage is the potential difference how potential drops as the current (amps) rises through the circuit ?
2) what makes the starter motor to draw more amps than the motorcycle horn? is that the resistance inside the device (motor) which directly affects the amperage? if we apply V=IR we can see that as we increase the resistance the amp value drops. if we decrease the resistance the amp value rises. but that's assuming the voltage is constant. so i'm not sure it's practical to apply it for this example ( sorry i have a very basic knowledge ).
3) is there a way to check the amp value of the starter motor? i have used volts,ohms,diode and continuity modes in my multimeter but haven't used it to measure amps so far.
thank you very much