It is spinning slower because you do not have the field terminal grounded. It is turning using only the residual magnetism in the pole shoes. It should motor just like it is with the way you have it hooked up and then speed up when you ground the F terminal to the case. When you ground the Field terminal you now will have the field coils adding electromagnetism to what the the pole shoes already have. The slow speed tests the armature. The faster speed is testing both armature and field coils.
I believe the problem is that the field tap is getting 12V instead of the motor/generator tap. The field circuit is good, but leaving that connected for more than a few seconds could burn up the field winding. Inflec was right about "motoring" but he was motoring the unit with the field coil rather than the Gen tap and coil. If he wanted to get the unit to act as a motor, then he should have applied +12V to the other tap (usually marked "Gen").
What you are doing is "motoring" the generator. It's turning slowly for two reasons: 1, you've prolly grounded the field, thus applying full excitation (magnetism). This will have the effect of slowing it as a motor. 2, when manufactured, these things are optimized for generator use (the brushes are positioned differently than they would be if this was intended to be a motor. You were right to ground the field, though.
Just make sure it’s not spinning too fast because the voltage will loop and it will eventually self destruct.. this is really only an issue if it’s being tested on a vehicle.
Actually to do this test connect F & D together then with the case grounded give power to the FD connection, it will go quicker as the field gets stronger. It's not proof positive but a fair assumption that all is ok.
It is spinning slower because you do not have the field terminal grounded. It is turning using only the residual magnetism in the pole shoes. It should motor just like it is with the way you have it hooked up and then speed up when you ground the F terminal to the case. When you ground the Field terminal you now will have the field coils adding electromagnetism to what the the pole shoes already have. The slow speed tests the armature. The faster speed is testing both armature and field coils.
I believe the problem is that the field tap is getting 12V instead of the motor/generator tap. The field circuit is good, but leaving that connected for more than a few seconds could burn up the field winding. Inflec was right about "motoring" but he was motoring the unit with the field coil rather than the Gen tap and coil.
If he wanted to get the unit to act as a motor, then he should have applied +12V to the other tap (usually marked "Gen").
What you are doing is "motoring" the generator. It's turning slowly for two reasons: 1, you've prolly grounded the field, thus applying full excitation (magnetism). This will have the effect of slowing it as a motor. 2, when manufactured, these things are optimized for generator use (the brushes are positioned differently than they would be if this was intended to be a motor.
You were right to ground the field, though.
Just make sure it’s not spinning too fast because the voltage will loop and it will eventually self destruct.. this is really only an issue if it’s being tested on a vehicle.
Actually to do this test connect F & D together then with the case grounded give power to the FD connection, it will go quicker as the field gets stronger. It's not proof positive but a fair assumption that all is ok.