DC motors and Generators questions

Not so long ago most cars were fitted with DC generators.

well my question has what d.c motor is required... then i have to identify another application for this motor.....

GA from me as you were right again!! Series windings are usual....

i have put:

The best motor to use to start up a vehicle is a shunt motor this has field windings that are connected in parallel (shunt) across the armature coil. The field strength is independent of the armature current. Shunt-motor speed varies only slightly with changes in load, and the starting torque is less than that of other types of dc motors

Now i really don't understand what connect/type it has..... grrrr

But you need loads of starting torque for a starter motor ...

Oh, Hell ... I'm doing your homework! Sorry, but that's a no-no on CR4 .

sorry i don't mean to get you into trouble. i just needed a push in the right direction. Il take a closer look at this and try to get somthing better. I know a single phse series motor gives high starting torque and considerable speed variation. but i don't know if it suitable for that app!

I won't get in trouble - it's a kind of unwritten rule. It's OK to give a shove in the right direction, but generally we steer away from much involvement on the basis that doing it yourself will help you a lot more in the end, than any number of answers you've been given there.

Have a good trawl around the net & do your best to produce a full & reasoned answer. If you get really stuck, come back & explain what you've found out and what your remaining problem is, & maybe you'll get another leg up.

Don't want to sound mean or head-up-my-arse-ish, but even unwritten rules is rules .

Good luck,

John

well so far this is pritty much all i have to finish, other than a d.c generator equation that just goes over my head! well i am going to go with a 'shunt d.c motor' for the vehicle. I had to find a motor for a overhead crane and after some research i found that a series motor would be best for that app. the car one got me good and proper. Well its in for tomorrow so il see what the other guys have done at college. Il only get it back to re do if i don't pass! such a difficult subject.!.!.!

Hey, hope it goes OK.

Don't feel you can only come back to take - I'm sure you've got lots to give.

Keep in touch - let us know how you get on.

You have to be careful when using series motors, they have no "natural" speed control. Lightly loaded, or even helped when going "down" as a crane motor, they will over speed and can eventually fly apart!!!

Also, reversing DC polarity does not reverse direction on a DC motor with field windings....as against one with a magnet stator/field (my terminology is not quite correct here, sorry).

If the connections to the brushes and fields are brought out of the motor you can not only reverse direction of rotation by reversing either the field(s) OR the brushes relative to the other, you can also wire it as series for the up direction and as a shunt for the down direction!!!

Do remember though that starter motors are not designed for longterm usage, bearings are generally quite simple and current usage is very high!!!!

You seem to be mixing AC motor terminology with DC motor terminology......do you have a clue what you are doing/talking about????

This response may not be entirely specific to your question but corporate jets use a DC starter to spool the engine up to ignition speed. As soon as the engine ignites, the starter switches it's operation from a starter to a generator, or something like that.

It's been years since I had any first hand access to that environmnt so it's possible that A: my memory is flawed and B: things have changed.

Caveate Empty!

L.J.