In need of electronics/circuit board knowledge

[Grahame Collins]

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[Pearo]

Can you whip of the serial number sticker so we can see whats under it? I have a good guess that its a switchmode controller IC, but if I know which one I can try look at where the potentiomer goes and see if it will affect the current limit. A quick gander at it looks like the pot goes to that IC.

[brendanh]

Can you whip of the serial number sticker so we can see whats under it? I have a good guess that its a switchmode controller IC, but if I know which one I can try look at where the potentiomer goes and see if it will affect the current limit. A quick gander at it looks like the pot goes to that IC.

I have no idea what tou mean. I dont have much experience in this area.

[brendanh]

If you're confident P2 is the wiper connection, then you should be able to short it to P1 or P3 (maybe using a 100 ohm resistor in the first instance to confirm) then measure the voltage on the motor terminals to see which way gives you max volts.

Shorted p2 to p1.
M+ to m- = 25v
M+ to p3 = 25v
M- to p1/p2 = 24v

However when i hook my new control to m+ and m- it goes straigh into fault mode.

[brendanh]

I also hooked up a motor directly to m+ and m- and the motor ran fine with no faults

[RustyArc]

However when i hook my new control to m+ and m- it goes straigh into fault mode.

What is this "control" that you're using?

[brendanh]

The pwm control for the motor.

[RustyArc]

The pwm control for the motor.

Could do with a little more information than that in order to work out why the controller is tripping the supply's current limiting, yet the motor doesn't. Do you have a photo or link for the controller you're using?

[brendanh]

Could do with a little more information than that in order to work out why the controller is tripping the supply's current limiting, yet the motor doesn't. Do you have a photo or link for the controller you're using?

http://pages.ebay.com/link/?nav=item...249267&alt=web thats the control. Ive used ine before on another project and i liked it.

[Pearo]

I have no idea what tou mean. I dont have much experience in this area.

There is a serial number sticker on one of the components. That components is what controls everything in the power supply. On top of that component will be a part number, maybe UC3000, or TL494 or similar. If you can give me that part number, I can attempt to reverse engineer the part of the circuit that does the speed control and current regulation.

[brendanh]

There is a serial number sticker on one of the components. That components is what controls everything in the power supply. On top of that component will be a part number, maybe UC3000, or TL494 or similar. If you can give me that part number, I can attempt to reverse engineer the part of the circuit that does the speed control and current regulation.

Thw numbers where pretty hard to read but i think it was kc724rf and k324n

[RayG]

I've used that PWM controller on different projects, it's a nice little board for the money.

I don't know why it's tripping your power supply current limit, it might be a current spike while charging the electrolytic cap, or it could even be a faulty board.

It's a single IRLR7843 FET pwm switching to ground, non reversible, Power Schottky flywheel diode. A 20 pin STM8 embedded controller doing all the smarts, 78M05 regulator, nothing much else to see.

If you are using it for power feed, how do you do reverse? If you reverse polarity on this board you'll probably zap it.

[brendanh]

I've used that PWM controller on different projects, it's a nice little board for the money.

I don't know why it's tripping your power supply current limit, it might be a current spike while charging the electrolytic cap, or it could even be a faulty board.

It's a single IRLR7843 FET pwm switching to ground, non reversible, Power Schottky flywheel diode. A 20 pin STM8 embedded controller doing all the smarts, 78M05 regulator, nothing much else to see.

If you are using it for power feed, how do you do reverse? If you reverse polarity on this board you'll probably zap it.

i have used the board no problem, it was part of a kit from little machine shop and used a double pole switch i believe it called.. as i said before the control for the motor speed is pretty and doesn't offer any slow speed its pretty muh 100-80%

i did a quick fit with the PWM control and found it was much better at the lower speeds. Im starting to think its going to be too hard to get the original board to feed the PWM and would be much easyer starting over, ive got my eye on a 2amp power supply that can feed the pwm control, im just lacking current limitating, i need it to cut out at 1amp. i was thinking about using a slow blow fuse buy a heap of them and replace as they blow?

[RustyArc]

A power supply like this would be more appropriate:
http://oceancontrols.com.au/PSM-2523.html

It's got current limiting, which at 25W and 24V is about an amp.

[RayG]

You can get small DC circuit breakers, they are resettable, or you could just put a polyfuse in circuit, they automatically reset when the power is cycled.