D.C. treadmill motor power supply

[joerm]

Hi folks, I dabble in electronics only enough to be dangerous but still I push ahead occasionaly as what ever project I have going requires. My latest project is trying to power an old 90v 9am d.c. treadmill motor with power supply from a newer random treadmill manufacturer. Mistakenly I thought it was 120v a.c. in and 120v d.c. out but it turns out the transformer is 120ac in and 120ac out with an additional 9v a.c. leg.
I noticed on the board that 120v a.c. out is indicated with diagonal lines drawn through the box (Pic attached) Could someone help me understand why that is? Also is it possible to power a d.c. motor with this power supply? (I've attached a crude pinout sketch up of the power supply board)

 

[joerm]

Does anyone know what is a cheap way to provide power/speed control to a DC permanent magnet treadmill motor ? I went ahead and bought a cycletrol 150 d.c. control, so I'm set for the motor mentioned above, but I mean for future reference are there cheap ways folks are taking advantage of cheap abundant treadmill motors picked up along the road, free on craigslist etc ?

 

[(*steve*)]

Well, as a hint, a transformer will always take AC in and put AC out.

If there are other components on the output side, they may be used to convert this AC into either pulsed DC, or a more smoothed DC.

I suspect that the shaded contacts you show are simply other connections to the 120V mains. Given the size of the transformer compared to the (presumably spade) connectors, it can't be an isolation transformer of any significant power.

Speed control of a DC motor is most often achieved using PWM. Perhaps the controller you purchased is one of these.

edit: The shading probably indicates "WARNING! WARNING! DANGER WILL ROBINSON!"

 

[joerm]

Thanks for your help Steve.. that was obviously a gentle way of saying "dude you're dangerous to yourself" )

"Speed control of a DC motor is most often achieved using PWM. Perhaps the controller you purchased is one of these."

I'm thinking that's what this board is (obviously guessing here) I've attached the pic again highlighting in yellow where on the board I suspect the potentiometer would have been connected, do you think? Also if that's true where would the 2 leads that power the DC motor connect to this board? I'm prepared to safely fry the board (which is useless to me now) while probing for the connections that might allow it to function with this motor.

 

[(*steve*)]

The three spade connectors labelled "neutral", "down", and "up" seem to be connections to the incline motor. However this appears to be an AC motor given the reference to neutral.

If you can find the part number of the three TO-220 components (The three legged black devices with a bolt securing them to the board via a metallic tab) then we *might* be able to figure out if this is phase control of AC or PWM control of DC.

edit it's possible the PWM control is for another motor??? How many does it have?

 

[joerm]

Interesting that the "Incline" power spades hint at an AC motor. The power supply I'm trying to use (with my older DC motor) comes from a newer treadmill which possibly could have had an AC motor? I was hoping that all or most of the treadmill makers out there were all using the same basic design of 120v ac source power and DC motors when I bought the power board..not so I've learned. My DC motor (thumbnailed in my first post) is much older and from a different treadmill manufacturer.

I scribbled the part #'s that you asked about in the attached pic. Hopefully these are what you meant?
Thanks!

 

[(*steve*)]

The 7805 is a 5V regulator. That almost certainly powers the logic on the top of that board.

The other two devices are not something I recognize. My guess is that they are triacs.

Can you read what is on the two white 6-pin devices in approximately the centre of the board. If these are opto-couplers with triac outputs, then that almost 100% confirms that the devices are triacs. I'm expecting something like an MOC3041 (because you're 110V, right?).

 

[KrisBlueNZ]

They are MOC3041s. You can read the part numbers (barely) in the photo.

 

[joerm]

Yes thank you the 2 white 6 pin devices are MOC3041's good eye KrisBlueNZ (I read the numbers off the actual board to confirm)
and yes the power inputs are calling for 120v (which we use here)
Thanks for all your help... (no clue here what all this means)