Simple speed control

[rarslan]

I'm trying to find a simple (reads "cheap&quot way of putting together an experimental setup where I can spin a flat surface (less than 4&quot to spread liquid on it. Max speed I need to achive is about 4000rpm. The load is almost negligable compared to motor rotor's own inertia probably. Most critical restriction is being able to start from zero speed and accelerate slowly to max speed. I cannot simply start from few hundred rpm. Could I simply get any DC motor and regulate the speed with input voltage? Can I add an additional weight to slow down the start up speed? Brushless vs brushed motors? I do not want to spend $2K plus to get a driver/controller/motor setups to experiment. Any input is appreciated. Thanks.
Ruhi

 

[EnergyEngineer]

Go to home depot and buy a power planner 10amp energy saving module. Take the four screws out open it and change the jumper setting from j1 to j2. There are two 10k pots, one says delay and dont mess with it. The other says correction factor and that will be your adjustible speed drive. It will handle 120 and 240 ac motors up to 10 amps. Have fun and it only cost 29.95.

Lance

 

[RickOzone]

Hi,

I'm not an expert on motors but I would guess that a DC motor would do the trick. 4000 rpm seems a bit high for common dc motors. I haven't heard of a brushless DC motor. You could use a simple bench adjustable DC power supply or a SCR speed controller. Be sure that the DC supply has enough voltage and current to supply the motor. Here is a link to a vendors DC motor info

http://www.grainger.com/Grainger/static.jsp?page=rc_dcmotorgd.html

that describes in a short form three kinds of DC motors.

 

[Warpspeed]

Hello Ruhi.

What you need is one of the combination ac/dc mains operated brush type motors. These are commonly found in household appliances such as vacuum cleaners and so on. They usually rotate at fairly high speeds, typically 10,000 to 15,000 RPM, but the big advantage is that the speed can be controlled by simply varying the supply voltage. This is something you cannot do with an induction motor.

If it was me, I would go out and buy a cheap router, and mount it somehow spindle upwards. You could then mount your disk in the very nice chuck provided on the router shaft. This will probably spin at 12,000 RPM or something.

You then find a sufficiently rated lamp dimmer, or motor speed controller, or maybe you might have a variac in your lab somewhere ?

Anyhow, you will be able to adjust your speed right down to zero. Two notes of caution. First at reduced speed there will be little airflow through the motor windings, but there will also be little power or load, so it should be o/k. Secondly speed control may not be smooth at low speed, and you might need a small flywheel to smooth it out.

Cheers, Tony.

 

[jbartos]

Suggestion: Visit

http://www.thomasregister.com

and type Motors: DC under Product or Service, which will return 293 companies to approach to