A
amdx
- Jan 1, 1970
- 0
I need some help explaining a motor I have been using for over a year.
It is a shunt field motor.
Please stick with me as I develop the situation.
If you know of better place to ask me question please let me know. (forums?)
I have a shunt field motor that I have been using with a series field
controller. I have been using this on an electric gokart and it has worked
fine for over a year.
Shortly after finishing the wiring and testing (it ran great btw) I realized
I made an error when wiring the shunt.
I wired it so no current flowed in the shunt, The wiring put a 20 ohm
resistor across the shunt. Here's a simplified schematic of the wiring.
The 20 ohm resistor is for current limiting, as I'm overvolting the motor.
http://i395.photobucket.com/albums/p...ringDiagrm.jpg
I wired it properly and the motor ran slower, so I ran the shunt open and
this cause my controller to become defective ( bad day). After I got the
controller fixed I wired it as original (no shunt current) and we have drove
it for a year.
Here's a link showing all three wiring diagrams.
http://i395.photobucket.com/albums/p...arioABCGIF.gif
So, how does this even work with the shunt wired to the 20 ohm resistor
and not current through the shunt? I expect some answer about current
induced by rotor flux, but we'll see.
Next problem, the motor smoked the other day, I pulled it apart and found
the field overheated. The field has 4 poles and is a bit odd. Two poles use
#16 wire and two use #24 wire. The field measures 41 ohms and has not
changed in the last year. I can't tell if the #16 and #25 are series or
parallel, however, I think it is a good guess they are in series because I
think the #16 wire fields would have much less than 41 ohms. The fields do
show opposite magnetic fields as I go around the stator. (Tested with small
magnet on a stick).
Here's a picture of the stator with two different wire sizes.
Note three different color wires in #16 wound field.
http://i395.photobucket.com/albums/p...vam/Stator.jpg
I understand the motor could have compound or interpole windings,
but I don't think either of these are true, based on my measurements.
Here's a diagram of the motor connection.
Only three wires out labeled A2, F1 and F2.
http://i395.photobucket.com/albums/p...2F2F1Motor.jpg
Here's the original motor wiring plate, I don't think it is relevant because
it is clear this motor has been rewound.
So, Why the different size wire in the field?
The #24 wire is overheated at one end of the motor, any idea why
it would have overheated, since I don't battery current through the shunt?
I will be happy to do any more measurements requested if I can.
Any help to enlighten me is appreciated.
Thanks, MikeK
It is a shunt field motor.
Please stick with me as I develop the situation.
If you know of better place to ask me question please let me know. (forums?)
I have a shunt field motor that I have been using with a series field
controller. I have been using this on an electric gokart and it has worked
fine for over a year.
Shortly after finishing the wiring and testing (it ran great btw) I realized
I made an error when wiring the shunt.
I wired it so no current flowed in the shunt, The wiring put a 20 ohm
resistor across the shunt. Here's a simplified schematic of the wiring.
The 20 ohm resistor is for current limiting, as I'm overvolting the motor.
http://i395.photobucket.com/albums/p...ringDiagrm.jpg
I wired it properly and the motor ran slower, so I ran the shunt open and
this cause my controller to become defective ( bad day). After I got the
controller fixed I wired it as original (no shunt current) and we have drove
it for a year.
Here's a link showing all three wiring diagrams.
http://i395.photobucket.com/albums/p...arioABCGIF.gif
So, how does this even work with the shunt wired to the 20 ohm resistor
and not current through the shunt? I expect some answer about current
induced by rotor flux, but we'll see.
Next problem, the motor smoked the other day, I pulled it apart and found
the field overheated. The field has 4 poles and is a bit odd. Two poles use
#16 wire and two use #24 wire. The field measures 41 ohms and has not
changed in the last year. I can't tell if the #16 and #25 are series or
parallel, however, I think it is a good guess they are in series because I
think the #16 wire fields would have much less than 41 ohms. The fields do
show opposite magnetic fields as I go around the stator. (Tested with small
magnet on a stick).
Here's a picture of the stator with two different wire sizes.
Note three different color wires in #16 wound field.
http://i395.photobucket.com/albums/p...vam/Stator.jpg
I understand the motor could have compound or interpole windings,
but I don't think either of these are true, based on my measurements.
Here's a diagram of the motor connection.
Only three wires out labeled A2, F1 and F2.
http://i395.photobucket.com/albums/p...2F2F1Motor.jpg
Here's the original motor wiring plate, I don't think it is relevant because
it is clear this motor has been rewound.
So, Why the different size wire in the field?
The #24 wire is overheated at one end of the motor, any idea why
it would have overheated, since I don't battery current through the shunt?
I will be happy to do any more measurements requested if I can.
Any help to enlighten me is appreciated.
Thanks, MikeK