- #1
hondaman520
- 33
- 0
ok, so I am coming from a complete automotive perspective so when i refer to voltage applied to an electric motor (engine starter motor for example) i mean 12v direct current. typically consisting of a battery that puts out 500 cranking amps..
the question is real simple but iv noticed auto technicians in the field have debate about it..
MY OBSERVATION:
following the rules of ohms law, when you close a circuit involving an electric motor, given the complete 12 volts it needs (in most automotive cases), the current output theoretically depends on the resistance of the electrical windings inside the electric motor, correct?
Now, I am not an engineer (yet), but its very obvious that when you apply a load or physical strain to an armature of a motor, it tends to draw more current, right? (Best analogy would be cranking an engine on a cold day, cause it requires more work to do so).
QUESTION:
i guess my question would be as simple as, when there is an increased load on the armature as its turning, is the electrical resistance in the motor DECREASING? it sounds like an odd phenomenon and i could be wrong. this sort of goes into my confusion between physical resistance and electrical resistance. which i'v noticed in cases where you have a faulty car starter motor, or a worn cabin blower motor, over time these tend to draw more current.
could someone enlighten me? maybe i wasnt correct in my observations, but this very phenomenon here is a fine distinction between diagnosing a bad car starter from a bad battery. from the perspective of a future mechanical engineer working in the automotive field, iv noticed that that the understanding of "difference between physical resistance of a load device and electrical resistance of that device" is diverse and widely misunderstood.
the question is real simple but iv noticed auto technicians in the field have debate about it..
MY OBSERVATION:
following the rules of ohms law, when you close a circuit involving an electric motor, given the complete 12 volts it needs (in most automotive cases), the current output theoretically depends on the resistance of the electrical windings inside the electric motor, correct?
Now, I am not an engineer (yet), but its very obvious that when you apply a load or physical strain to an armature of a motor, it tends to draw more current, right? (Best analogy would be cranking an engine on a cold day, cause it requires more work to do so).
QUESTION:
i guess my question would be as simple as, when there is an increased load on the armature as its turning, is the electrical resistance in the motor DECREASING? it sounds like an odd phenomenon and i could be wrong. this sort of goes into my confusion between physical resistance and electrical resistance. which i'v noticed in cases where you have a faulty car starter motor, or a worn cabin blower motor, over time these tend to draw more current.
could someone enlighten me? maybe i wasnt correct in my observations, but this very phenomenon here is a fine distinction between diagnosing a bad car starter from a bad battery. from the perspective of a future mechanical engineer working in the automotive field, iv noticed that that the understanding of "difference between physical resistance of a load device and electrical resistance of that device" is diverse and widely misunderstood.