DC Motor Query

[redlee]

I have this DC motor, can anyone tell me how to see if its good, I hooked it up to a 9V battery works both directions. I hook it up to the controller and it wont start without a bump. Controller is reading 65V on each leg. Dont know if thats correct or should it be reading 120V on each leg. Thanks

 

[BrianPetersen]

Maybe tell us something about that mysterious "controller", and how you "hook[ed] it up".

 

[redlee]

Its the controller that it came with, I checked the voltage at where its marked A1-A2 beside the L1-L2.

 

[redlee]

Just checked the Potentiometer, reads 407 Ohms to 0 Ohms seems to be working.
But it doesnt change the DC voltage at the A1-A2

 

[jraef]

A1,A2 are usually the terminal numbers for a contactor, so this controller may have been intended to work in conjunction with a contactor in series with the DC output. DC terminals are usually just marked + and -, but I don’t see any in that photo. There appear to be some wires going out of the top of the 2nd photo, what do they go to?


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[redlee]

No other wires its all contained once assembled.
Only wires coming out are the A1-A2 and the 110 black and white.

 

[Gr8blu]

If your 110 V connection is AC (typical output from a wall outlet, for example), then part of the controller is a rectifier to "create" the required DC input to the motor at A1-A2. For most DC machines, the nameplate voltage (in your case, 130), refers to the total difference between A1-A2. Note that this could appear as 130-to-0 (if one leg is tied to ground), or "plus 65"-to-"minus 65" because the neutral plane is somewhere in the middle. It could even be 14065-to-13935, if the "neutral" plane is up around 14 kV.

To start turning, the applied A1-A2 voltage has to exceed the back EMF voltage of the armature circuit. In the case of a gear motor like this, it also has to be enough to cover the voltage drop across the field (if it's electro-magnetic and not rare earth materials). And it has to produce enough torque to overcome the friction of the system (bearings, gears, etc.). If the motor spins up on a 9 V battery, there isn't a lot of back EMF, nor is there an electro-magnet main field.

Converting energy to motion for more than half a century

 

[redlee]

So if the motor starts on a battery is the motor ok or could it still be bad ?
Thanks for the help.

 

[waross]

I hesitate to disagree with my friend jraef. However I have seen quite a few DC motors marked A1, A2. Armature 1, Armature 2, to differentiate from F1 and F2. (Field 1 and you know the rest.)
(That was motor markings, not controller markings.)
How old is that equipment?
115 Volts hasn't been a standard voltage since the early 1950s. (But no everyone got the memo.)
The controller may have a failing capacitor. (Big blue cylinder)

--------------------
Ohm's law
Not just a good idea;
It's the LAW!