DC motor controllers

[whydontu]

Put a 100 watt (minimum) 120VAC filament light bulb in place of the motor. If it lights up the board is OK.

very odd. can you post a photo of the motor nameplate?

 

[DPittman]

Put a 100 watt (minimum) 120VAC filament light bulb in place of the motor. If it lights up the board is OK.

very odd. can you post a photo of the motor nameplate?

As you can see the brushes are less than ideal but seem okay with low 12volt voltage?

 

[VicHobbyGuy]

Put a 100 watt (minimum) 120VAC filament light bulb in place of the motor. If it lights up the board is OK.

If the bulb lights up and you can control the brightness with the pot would be the next step.

Did you put a fast blow fuse (15A?) in the AC line and DC line to the motor? And the pot wiper was connected to P2? And the 'Horsepower resistor' is the correct value?

It's interestng that your controller is labelled KBLC, not KBIC.

 

[DPittman]

No fuse in line. And yes I believe I have the wiper connected to P2. I'm going to try to hook up the light bulb test.

 

[whydontu]

motor nameplate looks well within the specs for the controller. If the lightbulb test works, wire the motor in parallel to the lamp and try again.

 

[DPittman]

Whew! The light bulb lit! What will running it with the motor tell me? I'm guess now that the brushes might be the fault?

 

[whydontu]

If the lightbulb lit, then the controller is probably working. These controllers tend to be all or nothing. Does the pot work to adjust the lightbulb brightness?

Having the lightbulb presents a steady load on the controller. Without the bulb, if the motor is arcing the load is fluctuating and might be confusing the controller.

Do you have the correct HP resistor?

 

[Tom O]

How’s the spring on the brushes? On my Craftex they heated up and lost some spring tension.

 

[DPittman]

If the lightbulb lit, then the controller is probably working. These controllers tend to be all or nothing. Does the pot work to adjust the lightbulb brightness?

Having the lightbulb presents a steady load on the controller. Without the bulb, if the motor is arcing the load is fluctuating and might be confusing the controller.

Do you have the correct HP resistor?

I "think" I have the right hp

resistor as it is supposed to be right for my 3/4 hp lathe motor. Pic attached.
Yes the pot works welll to adjust bulb brightness.
The brush springs seem fine to me.

 

[DPittman]

So does this look right for parallel wiring? Alligator wires on left will go to A+ and A- on the board and the red wire on the right goes to motor motor positive and the left black goes motor negative.

 

[whydontu]

So does this look right for parallel wiring? Alligator wires on left will go to A+ and A- on the board and the red wire on the right goes to motor motor positive and the left black goes motor negative.View attachment 22114

that’s it

 

[VicHobbyGuy]

If it were my experiment, I'd put the bulb in series with the motor to act as a current limiter. Or put the bulb in the AC line to limit current there.
Also, I'd definitely add those fuses to the system.

Are there green /red LEDs on the board as mentioned in the manual?

 

[VicHobbyGuy]

I "think" I have the right hp resistor as it is supposed to be right for my 3/4 hp lathe motor. Pic attached.

Yes, that looks about right for the resistor. Check that the CL (current limiter) pot is in the mid-point of its adjustment range, too.

 

[whydontu]

If it were my experiment, I'd put the bulb in series with the motor to act as a current limiter. Or put the bulb in the AC line to limit current there.
Also, I'd definitely add those fuses to the system.

Are there green /red LEDs on the board as mentioned in the manual?

from expensive experience, these controllers really dislike intermittent loads. Page 13 of the manual. Open armature wiring causes immediate release of the magic smoke. That’s why I suggest in parallel.

 

[DPittman]

Ok tried bulb in parallel and motor runs with a bit of sparking at low speed and bad sparking and bit of smoke as I cranked up the pot. Quit before all the magic smoke escaped. I'll see if I can find new brushes.

 

[VicHobbyGuy]

I'll see if I can find new brushes.

There's still a fair bit of carbon left on the brush in the picture, so you could use sandpaper around a dowel to sand back to a smooth curve. I've done that. Also, I have had a situation where that spring decided to just coil up in the passage and not press the brush down effectively. I'd try to have a look at the commutator if there was an easy way to do that, sometimes they get a dirty film which affects the contact.

 

[DPittman]

There's still a fair bit of carbon left on the brush in the picture, so you could use sandpaper around a dowel to sand back to a smooth curve. I've done that. Also, I have had a situation where that spring decided to just coil up in the passage and not press the brush down effectively. I'd try to have a look at the commutator if there was an easy way to do that, sometimes they get a dirty film which affects the contact.

Thanks for those suggestions. Yes the commutator does definitely have a film on it but not much wear.

 

[Tom O]

It looks like some particles are close to bridging maybe give them a scrape out while it’s apart.