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Simple DC motor control

I took some pics of my speed control last night.






33 rpm


45 rpm



This control takes around fifteen minutes to settle at the correct speed. I set it warm and it starts slightly slow but once warm runs right all night. The original built on vero runs fine straight away so I can only assume it's down to a component type. The 4.7R resistor Rs is different in the original controller, some kind of fancy expensive thing. Dunno if it's that really, just guessing.
 
Warm-up is an interestingissue. I'd suggest that the switch is a 'two-way with centre-off' type. Then you can leave the thing powered 24/7, keeping the diode nice and warm, but the motoronly runs when you pick a speed.
 
I would be up for a board too. As long as the prices didn't go up dramatically, I would think it would be worth doing revisions suggested by Martin.

BTW, what is the recommended VA/Voltage for the transformer (I would be using an Origin Live motor).
 
depends on what regulators you use, OL motors run under 10v so 12-15v trannies should be fine
 
Martin your suggestions on post#40, could they all be added as minor mods to the existing PCB for those that would like to experiment further? if so this would save the cost of a further revision, the tooling charge is what bumps the price, and this is probably going to be a one off £150, so not cheap :(

I have requested the price of 50x Rev I PCB's from my supplier and if there is enough interest for 50 Rev 1 PCB's then I will place an order for them, if others would like to expand on the circuit I can supply the Gerber files.

I will be putting together my own built PCB in the next few days using exaclty the same compnents as used for the original Vero-Board Proto build as this has worked faultlessly for several months and the results are very pleasing according to Chopsaw (Si) I will then send the newly completed board to Si for him to soak test it on his Linn, if it works to spec then I will draw up a BOM with Farnell part numbers for reference and workable motor voltage ranges, so more in a few days.

Paul
 
Yes, you could stuff them into the existing layout. It's only adding three parts - one R in the opamp +ve supply; one R in the +ve feedback line with a cap to ground.

The existing pads for connectors do accept wire instead, as in photo posted earlier, so no change required there.
 
martin clark said:
Yes, you could stuff them into the existing layout. It's only adding three parts - one R in the opamp +ve supply; one R in the +ve feedback line with a cap to ground.

The existing pads for connectors do accept wire instead, as in photo posted earlier, so no change required there.
Click to expand...
Probably it's best to keep it simple, ie make no changes. I'll up my order from 1 to 2.
 
A good practice for future projects/PCBs is to include a small breadboard area for any later tinkering and experiments. Even just a handful of spaced holes with an interconnect mesh and ready connections to nets such as power and ground can be very useful.
 
Drawing together the replies so far we have requests for boards from:

1 Starbuck
3 SQ225917
2 Clivem2
1 Bemused
1 337alant
1 Stackowax
1 GWM
2 Chris Marshall
1 Simeon

So that's 13 so far if I captured the numbers and names accurately.
 
I'll have one.

Then all that would be needed would be a motor, mounting plate and pulley. Simple.

Paul
 
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